Myocarditis and influenza A H1N1: a review of the literature

[tetano]

Myocarditis is inflammation of heart muscle (myocardium), most often due to infection by common viruses, nonviral pathogens or as a hypersensitivity response to drugs.
The definition of myocarditis varies, but the central feature is an infection of the heart, with an inflammatory infiltrate, and damage to the heart muscle, without the blockage of coronary arteries that define a heart attack (myocardial infarction) or other common noninfectious causes. Myocarditis may or may not include death (necrosis) of heart tissue. It may include dilated cardiomyopathy.
It can cause a mild disease without any symptoms that resolves itself, or it may cause chest pain, heart failure, or sudden death. An acute myocardial infarction-like syndrome with normal coronary arteries has a good prognosis. Heart failure, even with dilated left ventricle, may have a good prognosis. Ventricular arrhythmias and high-degree heart block have a poor prognosis. Loss of right ventricular function is a strong predictor of death.
In young adults, from 5 to 20% of all cases of sudden death are due to myocarditis.

The frequency of myocardial involvement in influenza infection
has varied and fulminant myocarditis associated with influenza infection is exceedingly rare as shown by previous papers, although this probability depends on low affinities to cardiac involvement of the influenza virus and/or the methods used to diagnose myocardial involvement and influenza
infection.
In the literature there are sporadic reports of myocarditis due to influenza.
The prevalence of myocardial involvement in influenza infection ranges from 0 to 11% depending on the diagnostic criteria used to define myocarditis (Mamas MA, Fraser D, Neyses L. Cardiovascular manifestations associated with influenza virus infection Int J Cardiol 2008;130:304-309)

However Greaves et al. using more sensitive and specific markers of myocardial injury demonstrate that the prevalence of myocarditis during acute influenza infection is substantially lower than previously thought. Although they were unable to conclude that no myocardial inflammation is present, it seems likely that this complication is rare (Greaves, K., Oxford, J. S., Price, C. P., Clarke, G. H. and Crake, T., 2003. The Prevalence of Myocarditis and Skeletal Muscle Injury During Acute Viral Infection in Adults. Archives of Internal Medicine, 163, pp. 165-168).

During the bad season 2003-04 in USA, one hundred fifty-three influenza-associated deaths among children were reported to the CDC by 40 state health departments. Six cases had diagnosis of myocarditis or pericarditis.
( Influenza-Associated Deaths among Children in the United States, 2003–2004
N Engl J Med 2005; 353:2559-2567).

During the same season, in UK autopsy reports and death registration certificated for seventeen fatal cases of laboratory confirmed influenza in children. Myocarditis was detected in two cases(12%). ( Fatal Cases of Influenza A in Childhood, PLoS ONE 4(10): e7671. doi:10.1371/journal.pone.0007671)


In Japan nine patients were treated under diagnoses of acute myocarditis during the winter of 1998-1999. Five (two males and three females, mean age 52 +/- 18 years) were examined with myocarditis associated with influenza A
Two patients had diagnoses of fulminant myocarditis
(Clinical manifestations of influenza a myocarditis during the influenza epidemic of winter 1998–1999 J Cardiol 2001;37:315-323)

Tissue samples obtained at autopsy from 45 case patients with fatal influenza B virus infection were evaluated by light microscopy and immunohistochemical assays for influenza B virus
Myocardial injury was seen in 20 (69%) of 29 case-patients for whom samples were available. Investigators found that 17 patients had evidence of myocyte damage, including 10 with myocarditis. They didn't find viral antigens in any of the myocardial samples, though rRT-PCR testing found evidence of influenza B from one patient's myocardial tissue.
Regarding the cardiac findings, the authors said they were surprised about how frequent evidence of cardiac damage was found, even when tests didn't reveal myocarditis ( Myocardial Injury and Bacterial Pneumonia Contribute to the Pathogenesis of Fatal Influenza B Virus Infection J Infect Dis. (2012) doi: 10.1093/infdis/jir861 ).



In the scientific database (pubmed) I counted less than 60 cases of myocarditis caused by influenza virus from 1950 to 2009.




In the past two years numerous studies document cases of myocarditis often fatal linked to A-H1N1 pandemic virus.
Myocarditis associated with the novel virus seem to be more common and more commonly associated with a severe form compared with previous seasonal influenza virus.
Certainly a better surveillance and better diagnostic tools has enabled us to discover a greater number of people affected, but there is no doubt that the very significant increase can be explained also and above all with a greater severity of pandemic virus.

Furthermore, it should be kept in mind that the cases detected are only a minority with respect to those that occur really becouse many are not recognized.

In the scientific literature I counted 132 cases of myocarditis (some cases might have been counted more than once), at least 60 described as fulminant and one of pericarditis.
I tried to collect all these studies and the result of my research is below.
At the end there are some cases I have found from other sources.







At first, the studies showing that there is a more or less serious cardiac involvement in the course of pandemic influenza

1) Right and left heart failure in severe H1N1 influenza A infection.
Eur Respir J. 2010 Jun 1.
Brown SM, Pittman J, Miller RR 3rd, Horton KD, Markewitz B, Hirshberg E, Jones J, Grissom CK.Intermountain Medical Center Murray, Utah.

Right ventricular (RV) dilatation (50-80%) and at least moderate systolic impairment (23%) were common, higher than the range described in general populations with ARDS. Left ventricular systolic dysfunction was present in 17% of patients. No single echocardiographic parameter was associated with 28-day mortality or ventilator-free days to 28 days.

http://www.ncbi.nlm.nih.gov/pubmed/20516055

2) Cardiac manifestations in patients with pandemic (H1N1) 2009 virus infection needing intensive care.
J Crit Care. 2011 Jul 5.
Chacko B, Peter JV, Pichamuthu K, Ramakrishna K, Moorthy M, Karthik R, John G.
Medical Intensive Care Unit, Christian Medical College Hospital, Vellore 632 004, India.

Thirty-seven patients presented at 6.4 (SD 3.2) days of illness. Four patients had valvular heart disease and 1 preexisting ischemic heart disease. Seventeen (46%) patients had evidence of myocardial injury. Twenty of 28 patients in whom an echocardiogram was clinically indicated had left ventricular systolic dysfunction. Of these, 14 patients were diagnosed as having myocarditis, and most of them (12 patients) developed it early. Myocarditis was associated with longer duration of vasoactive agents (OR 1.46, 95% CI 1.06-2.02) and mortality. Patients with elevated troponin I had an increased risk of death (OR 8.7, 95% CI 1.5-60). A higher mortality was observed in patients with left ventricular systolic dysfunction (OR 9.6, 95% CI 1.7-58) compared with those in whom an echocardiogram was normal or not indicated.
CONCLUSION:

In our cohort of severe P(H1N1)2009v infection, myocardial injury and dysfunction was frequent and associated with high mortality.

3) Cardiac injury in patients with pandemic 2009 influenza A (H1N1) infection.
Acta Cardiol. 2011 Aug;66(4):427-32.
Ni Z, Guo Z, Chen X, Wang Q, Qiu Y, Wu T, Yang Y, Zhao L.
Department of Emergency, First People's Hospital of Hangzhou, Zhejiang Province, People's Republic of China.

This retrospective study recruited one hundred and seventy-two patients with 2009 influenza A (H1N1) of different severity (non-severe, severe, critically severe) and 21 patients who were influenza A (H1N1)-negative but who had an influenza-like illness.
Myocardial injury was quite serious in severe infection by the influenza A (H1N1) virus, particularly in critically severe patients. Patients with 2009 influenza A (H1N1) had injury and dilation of the heart, which may be a potential cause of death


4) Reversible Cardiac Dysfunction Associated With Pandemic 2009 Influenza A(H1N1)
Chest. 2010 May;137(5):1195-7.
1. Seth S. Martin, MD, 2. Caroline L. Hollingsworth, MD, MPH, 3. Stephanie G. Norfolk, MD, 4. Cameron R. Wolfe, MBBS and 5. John W. Hollingsworth, MD

We identified that 4.9% (6/123) of patients had either new or worsened left ventricular dysfunction. These cases ranged in age from 23 to 51 years, and all had preexisting medical conditions. ICU level care was required in 83% (5/6) of the cases. Sixty-seven percent (4/6) of the cases had follow-up echocardiograms, and left ventricular function improved in all four. We conclude that potentially reversible cardiac dysfunction is a relatively common complication associated with hospitalized pandemic A(H1N1) influenza.

http://chestjournal.chestpubs.org/co...95.short?rss=1

5) Echocardiographic manifestations of pandemic 2009 (h1n1) influenza a virus infection.
J Infect. 2010 Apr 26.
Erden I, Erden EC, Ozhan H, Basar C, Yildirim M, Yalçin S, Aydin LY, Dumlu T.
Duzce University Düzce Medical School Department of Cardiology, Konuralp/Düzce, TURKEY.


The results of the study suggest an association between hospitalized pH1N1 and subclinical cardiac dysfunction as measured by tissue Doppler echocardiography

http://www.flutrackers.com/forum/sho...ht=myocarditis


6) Myocarditis as a complication of influenza A (H1N1): evaluation using cardiovascular magnetic resonance imaging
Hellenic J Cardiol. 2010 Jul-Aug;51(4):379-80
Mavrogeni S, Manoussakis MN.

Of the 100 patients studied, 20/100 presented with mild chest discomfort, 50/100
with sinus tachycardia, 25/100 with dyspnoea and 5/100 with severe chest pain radiating to both arms. An abnormal ECG, with ST elevation equal to 1 mm in II, III and aVF, was found in 2/5 patients with severe chest
pain and a normal echocardiogram (without wall motion abnormalities, pericardial effusion or impaired ejection fraction). Myocardial phosphocreatine (CK-MB) was 62 ng/ ml in one and 82 ng/ml in the other (normal values <3.6 ng/ml), while troponin (Tn) was 6.9 ng/ml and 10 ng/ml (normal values <0.10 ng/ml), respectively. All patients with abnormal cardiac findings (mild chest discomfort, sinus tachycardia, dyspnoea and severe chest pain radiating to both arms) were young, with concurrent pneumonia and no history of systemic disease.

http://www.hellenicjcardiol.com/arch...2010_4_379.pdf

7) Electrocardiographic Abnormalities in Patients With Novel H1N1 Influenza Virus Infection
Am J Cardiol 2010; DOI: 10.1016/j.amjcard.2010.06.078
Akritidis N, Mastora M, Baxevanos G, et al.

Electrocardiographic (ECG) abnormalities were evaluated in a series of 50 patients with confirmed novel H1N1 influenza infection.
Of the 50 patients, 14 (28%) exhibited ECG changes on admission. Nine patients presented with T-wave inversions, while ST-segment depression was observed on the electrocardiograms of 6 patients. The presence of ECG changes did not correlate with age, gender, co-morbidities, the laboratory profiles of the patients, or the coexistence of lower respiratory tract involvement. None of the patients exhibited alterations in cardiac-specific biochemistry or cardiac ultrasonography. All ECG changes were transient and reversed during disease regression.
In conclusion, ECG abnormalities are frequently encountered during novel H1N1 influenza infection, but their presence does not indicate a direct pathogen effect to the myocardium; these alterations may necessitate admission in the first place but are transient and not correlated with preexisting patient characteristics or with outcomes.


http://www.ajconline.org/article/S00...418-9/abstract

8) Analysis on the Myocardial Injury of A/H1N1 Influenza Infection
Medical Research

Objective:To observe whether there was more serious myocardial injury in the patients with A/H1N1 Influenza than the patients with ordinary influenza.Method:The clinical data of 68 patients with A/H1N1 Influenza were investigated, which were divided into light group of 25 cases and heavy group of 43 cases. The level of serum CK-MB of the patients in light group were determined at 24 hours after admission. The levels of serum CK-MB and cTnI of the patients in heavy group were determined at 24 hours and 72 hours after admission.75 patients with ordinary influenza were treated as the control group.Results:The levels of CK-MB and cTnI of the patients with A/H1N1 Influenza were higher than the patients with ordinary influenza (P<0.05). Moreover, the levels of CK-MB of the patients with A/H1N1 Influenza in heavy group were higher than that in light group (P<0.05). There was no difference in the levels of CK-MB between the patients with ordinary influenza in heavy group and in light group(P>0.05).The proportion of the myocardial injury of the patients with A/H1N1 Influenza were higher than the patients with ordinary influenza.Conclusions:The patients with A/H1N1 Influenza have more serious myocardial injury compared with the patients with ordinary influenza. To reduce the mortailty,we treat the A/H1N1 influenza in the anti-virus protection, should enhance myocardial nutrition,too.

http://www.res-medical.com/medical-paper/111712

9) Myocardial dysfunction during H1N1 influenza infection.
J Crit Care. doi: 10.1016/j.jcrc.2013.01.010
Fagnoul D, Pasquier P, Bodson L, Ortiz JA, Vincent JL, De Backer D.

RESULTS:

Forty-six patients were admitted with severe H1N1 infection. Echocardiography was obtained in 39 patients on admission: 28 (72%) had abnormal ventricular function, of whom 13 (46%) had isolated LV abnormalities, 11 (39%) had isolated RV dysfunction, and 4 (14%) had biventricular dysfunction. Echocardiography was repeated in 19 of the 39 patients during their hospitalization: RV function tended to worsen with time, but LV function tended to normalize. The ventricular abnormalities were not associated with history, severity of the respiratory failure, or hemodynamic status. However, patients with ventricular dysfunction needed more aggressive therapy, including more frequent use of vasopressor and inotropic agents and of rescue ventilatory strategies, such as inhaled nitric oxide, prone positioning, and extracorporeal membrane oxygenation.
CONCLUSIONS:

These observations emphasize the high incidence of cardiac dysfunction in patients with H1N1 influenza infections.

http://www.ncbi.nlm.nih.gov/pubmed/23566732

In this part, the studies in which is assessed the incidence of myocarditis in groups of children severely ill or dead. The incidence varies from 1.3% to 5%


1) Deaths associated with pandemic (H1N1) 2009 among children, Japan, 2009-2010.
Emerg Infect Dis. 2011 Nov;17(11):1993-2000.
Okumura A, Nakagawa S, Kawashima H, Muguruma T, Saito O, Fujimoto J, Toida C, Kuga S, Imamura T, Shimizu T, Kondo N, Morishima T.
Juntendo University Faculty of Medicine, Tokyo, Japan.

198 patients in Japan with pandemic (H1N1) 2009 had died, of whom 41 were children <20 years of age.
Cause of death was categorized as unexpected cardiopulmonary arrest (CPA) for 15 patients, encephalopathy for 15, respiratory failure for 6, myocarditis for 2, viral sepsis for 2, and incidental for 1
Unexpected CPA was another leading cause of death associated with pandemic (H1N1) 2009 among children in Japan ….. Abrupt onset of CPA suggests a cardiogenic origin such as fatal arrhythmia from undetected myocarditis

http://www.thefreelibrary.com/Deaths.....-a0272807225

2) Characteristics of severely and critically ill children with 2009 influenza A (H1N1) virus infection.
Zhonghua Er Ke Za Zhi. 2010 Aug;48(8):571-574.
Lu ZW, Deng JK, Zheng YJ, He YX, Yang WG, Wei JR, Zhang JS, Li BN, Li XN, Song P, Yu ZZ, Zhao H, Wang L, Ma YJ, Tang ZZ, Liu XL, Li YZ, Li CR.
Department of Respiratory Diseases, Shenzhen Children's Hospital, Zunyi Medical College, Shenzhen 518026, China.

Among 150 severely and critically ill children with 2009 influenza A (H1N1) virus infection…..pneumonia (65%), encephalopathy (12%), myocarditis (5%), encephalitis (1%) and myositis (1%)

http://www.ncbi.nlm.nih.gov/pubmed/21055298

3) Multi-center investigation of the hospitalized children with 2009 influenza A (H1N1) infection.
Zhonghua Er Ke Za Zhi. 2010 Oct;48(10):733-8.
2009 Influenza A (H1N1) Clinical Case Investigation Group.

Of the 810 hospitalized children with 2009 influenza A (H1N1) infection……Clinical complications included pneumonia 586 (72.3%), encephalopathy/encephalitis 49 (6.0%), and myocarditis 30 (3.7%)

http://www.ncbi.nlm.nih.gov/pubmed/21176479

4) Clinical characteristics of Korean pediatric patients critically ill with influenza A (H1N1) virus.
Pediatr Pulmonol. 2010 Jul 20.
Shin SY, Kim JH, Kim HS, Kang YA, Lee HG, Kim JS, Lee JK, Kim WK.
Korea Centers for Disease Control and Prevention (KCDC), Division of Epidemic Intelligence Service, Seoul, Korea.

Of the 30 patients, 14 died and 16 were discharged from the hospital with complete recovery. The median patient age was 7 years (range, 2 months to 18 years). Nineteen patients belonged to the high-risk group. Cough was the most common initial symptom, followed by fever. In most patients, serum levels of C-reactive protein and lactate dehydrogenase were elevated. Oseltamivir, an antiviral agent, was administered to 29 patients. The most common causes of death were encephalopathy and myocarditis, with a higher mortality rate in the high-risk group

http://www.ncbi.nlm.nih.gov/pubmed/20648671

5) Critically Ill Children During the 2009–2010 Influenza Pandemic in the United States
Pediatrics doi: 10.1542/peds.2011-0774
Randolph AG, Vaughn F, Sullivan R, Rubinson L, Thompson BT, Yoon G, Smoot E, Rice TW, Loftis LL, Helfaer M, Doctor A, Paden M, Flori H, Babbitt C, Graciano AL, Gedeit R, Sanders RC, Giuliano JS, Zimmerman J, Uyeki TM; Pediatric Acute Lung Injury and Sepsis Investigator's Network and the National Heart, Lung, and Blood Institute ARDS Clinical Trials Network.

We identified children (<21 years old) with confirmed or probable pH1N1 admitted to 35 US PICUs from April 15, 2009, through April 15, 2010. We collected data on demographics, baseline health, laboratory results, treatments, and outcomes.

Of 838 children with pH1N1 admitted to a PICU.. In multivariable analyses, preexisting neurologic conditions or immunosuppression, encephalitis (1.7% of cases), myocarditis (1.4% of cases), early presumed MRSA lung coinfection, and female gender were mortality risk factors

6) Unchanged Severity of Influenza A(H1N1)pdm09 Infection in Children during First Postpandemic Season
Emerg Infect Dis. 2012 Nov;18(11):1755-62. doi: 10.3201/eid1811.120719
Altmann M, Fiebig L, Buda S, von Kries R, Dehnert M, Haas W.

ARDS (OR 3.2, 95% CI 1.1–9.2, p = 0.029), myocarditis (OR 30.9, 95% CI 2.6–360.7,; p = 0.006), and mechanical ventilation (OR 18.3; 95% CI 1.3–251.6, p = 0.030) were independently associated with a fatal outcome in the multivariable model after adjusting for age, sex, and season.
...Myocarditis was also highly associated with death in children; this finding supports those among adults (29,30) and other findings among A(H1N1)pdm09-infected children (31).

http://wwwnc.cdc.gov/eid/article/18/...19_article.htm

7) Predictive clinicopathological features derived from systematic autopsy examination of patients who died with A/H1N1 influenza infection in the UK 2009–10 pandemic
S Lucas* Department of Histopathology, St Thomas’ Hospital, London, UK DOI: 10.3310/hta14550-02 2010; Vol. 14: No. 55, 83–114

There is debate over whether H1N1 and other type A influenza viruses directly cause myocarditis. In this study, 3/19 children were stated to have myocarditis on histopathology, in association with H1N1-related influenza pneumonitis. But despite virology in two cases, H1N1 was not isolated from the heart tissue. Unfortunately, in investigating presumed acute viral myocarditis, in all age groups, it is uncommon to identify the specific agent in the tissue. No adults were noted to have myocarditis.

http://www.journalslibrary.nihr.ac.u...ta14550-02.pdf

Myocarditis in the general population

A national survey on myocarditis associated with influenza H1N1pdm2009 in the pandemic and postpandemic season in Japan J Infect Chemother.PMID:23089894
Ukimura A, Ooi Y, Kanzaki Y, Inomata T, Izumi T.

Twenty-nine patients with influenza A H1N1pdm2009 myocarditis were reported, with 25 from the 2009/2010 season and only 4 patients from the 2010/2011 season. Morbidity and mortality was 28 % (8/29) among all the myocarditis patients. Six patients with myocarditis were complicated by pneumonia. Myocarditis was proved by endomyocardial biopsy or autopsy in 9 patients, although histological findings showed mild myocarditis even in clinically defined fulminant myocarditis cases. Seventeen patients were diagnosed with fulminant H1N1pdm2009 myocarditis with fatal arrhythmias or varying degrees of cardiogenic shock. Fifteen fulminant myocarditis patients were seen in the 2009/2010 season and only 2 in the 2010/2011 season....The number of patients with myocarditis associated with influenza A virus seemed to increase in the pandemic season.

http://www.ncbi.nlm.nih.gov/pubmed/23089894

Studies concerning individual cases

1) Fulminant Myocarditis Associated With Pandemic H1N1 Influenza A Virus in Children
J Am Coll Cardiol, 2010; 55:928-929, doi:10.1016/j.jacc.2010.01.004

Andr&#225;s Bratincs&#225;k, MD, PhD*, Howaida G. El-Said, MD, PhD, John S. Bradley, MD, Katayoon Shayan, MD, Paul D. Grossfeld, MD and Christopher R. Cannavino, MD * Rady Children's Hospital–San Diego, University of California San Diego, School of Medicine, 3020 Children's Way, MC5004, San Diego, California 92123

Fulminant myocarditis is an uncommon complication, typically diagnosed in association with circulatory collapse or at autopsy in patients with influenza-associated fatal outcomes (5)

Here we present the first known report of acute myocarditis in pediatric population associated with the present pandemic H1N1 influenza A virus infection. Four cases occurred within a 30-day period, and 3 of them were diagnosed as fulminant myocarditis with fatal or near-fatal outcomes.

http://content.onlinejacc.org/cgi/co....2010.01.004v1

2) Myocarditis associated with 2009 influenza A (H1N1) virus in children
Cardiology in the young (2010), 20 : pp 351-352
DOI: 10.1017/S104795111000020X
Alban-Elouen Baruteaua1a2 c1, Nicolas Boimonda1 and Duksha Ramfula1
a1 CHR F&#233;lix Guyon, Service de R&#233;animation N&#233;onatale et P&#233;diatrique, Saint-Denis de La R&#233;union, F-97405, France
a2 Centre Chirurgical Marie Lannelongue, Service des Cardiopathies Cong&#233;nitales, Le Plessis Robinson, F-92350, France

three hospitalized children developed myocarditis during the epidemic wave in Reunion Island ( Indian Ocean).. Myocarditis was fulminant in two cases, presenting with an acte-onset heart failure and cardiogenic shock


http://journals.cambridge.org/action...ne&aid=7713212

3) 2009 Pandemic H1N1-associated Myocarditis in a Previously Healthy Adult
Clin Microbiol Infect. 2010 Jul 15.
Haessler S, Paez A, Rothberg M, Higgins T.


We report on a case of myocarditis due to documented 2009 pandemic H1N1 influenza in a previously healthy adult

http://www.ncbi.nlm.nih.gov/pubmed/20636418

4) A National Survey on Myocarditis Associated With the 2009 Influenza A (H1N1) Pandemic in Japan.
Circ J. 2010 Aug 6.

Ukimura A, Izumi T, Matsumori A; Clinical Research Committee on Myocarditis Associated with the 2009 Influenza A (H1N1) Pandemic in Japan organized by the Japanese Circulation Society.
Department of General Internal Medicine, Osaka Medical College.

The diagnosis of myocarditis was performed using the Guidelines for the Diagnosis and Treatment of Myocarditis (JCS 2009).
Fifteen patients were reported to the committee. Fulminant myocarditis developed in 10 patients.
The clinical manifestations of myocarditis caused by influenza pandemic A (H1N1) varied greatly, and 10 patients were diagnosed with fulminant myocarditis with fatal arrhythmias, and/or varying degrees of cardiogenic shock. Cardiopulmonary
arrest was the first cardiac symptom in 2 patients. Syncope due to complete AV block was the first cardiac symptom in 1 patient, who was rescued with temporary pacemaker implantation. The clinical course of patients also
varied. Cardiac dysfunction progressed rapidly in 12 patients;
myocarditis associated with pandemic influenza A (H1N1) seemed to be more common in hospitalized patients, compared with previous seasonal influenza virus outbreaks.

http://www.jstage.jst.go.jp/article/...4/10/2193/_pdf

5)Point-of-Care Sonography in the Emergency Department Diagnosis of Acute H1N1 Influenza Myocarditis.
J Ultrasound Med. 2010 Sep;29(9):1361-4.
Bramante RM, Cirilli A, Raio CC.
Department of Emergency Medicine, North Shore University Hospital, 300 Community Dr, Manhasset, NY 11030 USA.

Myocarditis is an uncommon diagnosis that must be considered in young patients with acute myocardial dysfunction. Several infectious agents have been noted as causes of acute myocarditis; however, most cases are idiopathic in nature. This diagnosis may go unrecognized initially in patients presenting with atypical symptoms. We report a rare case of H1N1-related acute myocarditis diagnosed with point-of-care sonography in the emergency department (ED).
A 7-year-old girl presented to the ED with a chief symptom of abdominal pain after a 3-day course of fever, cough, myalgia, vomiting, and malaise.

http://www.jultrasoundmed.org/content/29/9/1361.full

6) Fulminant fatal swine influenza (H1N1): Myocarditis, myocardial infarction, or severe influenza pneumonia?
Heart Lung. 2010 Sep-Oct;39(5):453-8.
Cunha BA, Syed U, Mickail N.
Infectious Disease Division, Winthrop-University Hospital, Mineola, New York, and State University of New York School of Medicine, Stony Brook, New York.

We present a case of rapidly fatal H1N1 in a young adult treated with oseltamivir and peramivir. He was initially tachycardic, thought to represent myocarditis. He subsequently became hypotensive and expired. At autopsy there was cardiomegaly present but there were no signs of acute myocardial infarction or myocarditis. Pathologically, he died of severe H1N1 pneumonia and not bacterial pneumonia.

http://www.ncbi.nlm.nih.gov/pubmed/20831976

7) Fatal fulminant myocarditis associated with novel influenza A (H1N1) infection.
Eur Heart J. 2010 Sep 22.
Komai T, Nakazawa G, Asai S, Ikari Y.
Department of Cardiology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.


A 51-year-old male presented to a local hospital with deteriorating general fatigue. The patient had reportedly been well until 2 days earlier when he began to have general fatigue. Because the blood pressure was as low as 70/40 mmHg, he was transferred to our hospital
A microscopic examination of the myocardium revealed infiltration of the inflammatory cell consisting of CD3-positive lymphocytes, macrophages, and occasional neutrophils (Panel D). Reverse transcriptase–polymerase chain reaction using autopsy specimen showed that influenza A (H1N1) M2 gene unique to novel influenza was positive in the left ventricle, the right ventricle, and the left lung

http://eurheartj.oxfordjournals.org/...tj.ehq359.full

always by the same authors: Responses to this article

A 51-year-old female reported a high temperature of 38 degree Celsius, general fatigue, headache, and loss of appetite to a local hospital. She was referred to our hospital for further evaluation. An initial influenza rapid antigen test was negative. On the next morning, she suddenly complained of chest pain and dyspnea. Laboratory data showed elevated WBC of 18,200/micro-L, CK of 703U/L with 5.6% of CK-M, and Troponin I of 4.82ng/mL. A rapid influenza test against influenza A virus using a nasopharyngeal-swab specimen was negative for the second time. An electric cardiogram revealed poor R progression and low voltage. Transthoracic echocardiography revealed left ventricular dysfunction with an ejection fraction of 32%, marked thickness of the left ventricular wall, and a small amount of circumferential pericardial effusion. She rapidly went into a shock state. Although she was treated with aggressive pharmacological and mechanical circulatory supports, she experienced cardiac arrest and could not be resuscitated. RT-PCR assay using a nasopharyngeal-swab specimen demonstrated the presence of novel influenza A (H1N1) virus.

http://eurheartj.oxfordjournals.org/...ply#ehj_el_829

8) Myocarditis Due to Pandemic Influenza A (H1N1).
Rev Esp Cardiol. 2010 Nov;63(11):1386-1387.
Penela D, Regueiro-Cueva A, Ortiz-P&#233;rez JT, Sitges M.
Servicio de Cardiolog&#237;a. Instituto del T&#243;rax. Hospital Clinic. Institut d'Investigacions Biom&#232;diques August Pi i Sunyer (IDIBAPS). Universidad de Barcelona. Barcelona. Espa&#241;a.

A 42-year-old male patient was admitted to the hospital with fever and chest pain complaints.The patient had a history of human immunodeficiency virus (HIV) which was diagnosed 15 years before the hospital admission.
Our case differs from those previously published because it is not a child and expands the population susceptible to this complication. Therefore, H1N1 influenza should now be considered in the differential diagnosis of viral myocarditis, since prompt initiation of oseltamivir may alter the clinical course of the disease. Whether current antiviral therapies may also limit cardiac involvement is largely unknown and deserves further investigation.ection,
http://www.revespcardiol.org/en/revi...al-editor-2010

9) A child with influenza A (H1N1)-associated myocarditis rescued by extracorporeal membrane oxygenation.
J Artif Organs. 2010 Nov 19.
Oda T, Yasunaga H, Tsutsumi Y, Shojima T, Zaima Y, Nishino H, Ito S, Todo K.
Department of Cardiovascular Surgery, St. Mary's Hospital, 422 Tsubukuhon-machi, Kurume, Fukuoka, 830-8543, Japan,

A 6-year-old boy had cold-like symptoms and was diagnosed with influenza A at a clinic. Administration of oseltamivir and azithromycin did not improve the symptoms. He was referred to our hospital and was diagnosed with H1N1 pneumonia. The patient required ventilator support. However, hypoxia and hypercapnia were uncontrollable. To oxygenate and reduce the carbon dioxide concentration, veno-venous extracorporeal membrane oxygenation (ECMO) was applied 24 h after admission. We established outflow via the right internal jugular vein and inflow via the right femoral vein. Six hours later, an electrical storm of ventricular fibrillation occurred, probably due to influenza myocarditis.

http://www.ncbi.nlm.nih.gov/pubmed/21088859

10) A Case of Acute Myocarditis Caused by Pandemic (H1N1) 2009 Influenza Virus
J Formos Med Assoc. 2010 Nov;109(11):857-8.
Pavlidis AN, Giannakopoulos AK, Danias PG, Manolis AJ.
Department of Cardiology, Asklepeion General Hospital, Athens, Greece.
No abstract available

http://www.ncbi.nlm.nih.gov/pubmed/21126658

11) Sudden death of an immunocompetent young adult caused by novel (swine origin) influenza A/H1N1-associated myocarditis.
Virchows Arch. 2011 Jan 14.
Gdynia G, Schnitzler P, Brunner E, Kandolf R, Bl&#228;ker H, Daum E, Schnabel P, Schirmacher P, Roth W.
Institute of Pathology, University Hospital, Im Neuenheimer Feld 220/221, 69120, Heidelberg, Germany.
Here, we report a fatal case of acute interstitial myocarditis associated with novel influenza A/H1N1 infection in an immunocompetent young woman. A previously healthy 18-year-old woman experienced malaise, diarrhea, and fever for several days prior to a sudden collapse at home. Autopsy revealed a predominantly lymphocytic myocarditis in the absence of a significant respiratory tract infection. Infection with novel (swine origin) influenza A/H1N1 was confirmed by PCR analysis of blood as well as myocardial tissue.

http://www.ncbi.nlm.nih.gov/pubmed/21234762

12) A case of myocarditis mimicking acute coronary syndrome associated with H1N1 influenza A virus infection.
Turk Kardiyol Dern Ars. 2010 Dec;38(8):572-5.
Sahin DY, Demir M, Kurtaran B, Usal A.

We report on a case of acute fulminant myocarditis caused by H1N1 influenza A virus infection that mimicked acute coronary syndrome. A 50-year-old man was admitted with dyspnea, fever, cough, vomiting, and atypical chest pain of three-day history.
Echocardiographic examination showed anteroseptal, apical, and lateral wall hypokinesia, left ventricular diastolic dysfunction, and dilatation of all the chambers. There was no abnormal finding on coronary angiography. The diagnosis was considered to be myocarditis;
Nasopharyngeal samples were positive for H1N1 influenza A virus.

http://www.ncbi.nlm.nih.gov/pubmed/21248460

13) Fulminant myocarditis associated with novel H1N1 influenza A
Kho Heart Lung. 2011 Mar 14.
Uzam RN, Parizianu C, Hafiz AM, Chawla S, Schwartz R.
Division of Cardiology, Winthrop University Hospital, Mineola, New York.
We describe a 36-year-old man with no significant medical history who presented with flu-like symptoms of 3-week duration. When he sought medical attention, he was already manifesting heart failure secondary to fulminant myocarditis, along with multiorgan failure. Despite aggressive management, including circulatory support with a catheter-based mechanical cardiac assist device (Impella 2.5 Cardiac Assist Device, Abiomed, Danvers, MA) as a bridge to cardiac transplant, and aggressive antiviral and antibacterial therapy, the patient died of cardiac arrest. An H1N1 polymerase chain reaction postmortem assay produced positive results, and a diagnosis of fulminant viral myocarditis and multiorgan system failure was established.

http://www.ncbi.nlm.nih.gov/pubmed/21411147

14) Fulminant myocarditis in an adult with 2009 pandemic influenza A (H1N1 influenza) infection.
J Chin Med Assoc 2011 Mar;74(3):130-3.
Liao YC, Hsieh YC, Chang WC, Huang JL, Ting CT, Wu TJ.
Cardiovascular Center, Taichung Veterans General Hospital, Taichung, Taiwan, ROC.

We present an adult who contracted H1N1 infection followed by fulminant myocarditis. Early implementation of extra-corporeal membrane oxygenation support in conjunction with a specific anti-influenza viral medication (Oseltamivir) led to the patient's complete recovery from cardiogenic shock in 2 weeks.

http://www.ncbi.nlm.nih.gov/pubmed/21421208

15) Influenza Myocarditis and Myositis: Case Presentation and Review of the Literature.
Can J Cardiol. 2011 Jun 6.
Kumar K, Guirgis M, Zieroth S, Lo E, Menkis AH, Arora RC, Freed DH.
We describe the case of a patient who presented to our center with concomitant "seasonal" H1N1 influenza A myocarditis further complicated by pan-myositis. The patient's condition rapidly declined, eventually requiring biventricular mechanical support, in addition to multilimb fasciotomies. The cardiac support required was progressive, from a percutaneous left ventricular assist device, to extracorporeal membrane oxygenation, to eventual biventricular assist device support for bridge-to-transplantation. This case motivated a detailed review of the literature (a total of 29 cases were identified), in which we found that patients with influenza myocarditis/myositis were predominantly female (63%) and young (mean age 33.2 years) and continue to have a high incidence of morbidity and mortality (27%). As a result of its atypical pattern, the 2009 H1N1 pandemic strain has gained attention. From our review, we found 7 patients with of 2009 H1N1 pandemic influenza myocarditis.

http://www.ncbi.nlm.nih.gov/pubmed/21652168

16) Influenza A (H1N1) and myocarditis.
Heart. 2011 Jun 14.
Khambekar SK, Harden S, Corbett S.
Source
Southampton General Hospital, Southampton, UK.
A 47-year-old woman was admitted with flu-like symptoms and dyspnoea, needing admission to intensive care. Having tested positive for H1N1 virus on nasal swab, she received a course of oseltamivir.

Two days later, while still being ventilated, she developed ST elevation in inferolateral leads on ECG ( panel A ) with raised troponin I of 95 μg/l (normal <0.07). Due to her …
http://heart.bmj.com/content/early/2...1.227975.short

17) Inusual association of ST-T abnormalities, myocarditis and cardiomyopathy with H1N1 influenza in pregnancy: two case reports and review of the literature
Journal of Medical Case Reports 2011, 5:314
Karen ChanDavid MeekIndranil Chakravorty

We report the cases of two pregnant Caucasian women (aged 29 and 30), with no pre-existing illness, presenting with respiratory manifestations of H1N1 influenza virus infection in their third trimester. Both women developed evidence of myocarditis.

One woman developed acute respiratory distress syndrome, almost reaching the point of requiring extra-corporeal membrane oxygenation, and subsequently developed persistent cardiomyopathy; the other recovered without any long-term consequence.
http://7thspace.com/headlines/389281...iterature.html

18) Influenza A positive but H1N1 negative myocarditis in a patient coming from a high outbreak region of new influenza.
Cardiol J. 2011;18(4):441-5.
Himmel F, Hunold P, Schunkert H, Bode F.
We present the case of a 21 year-old man holidaying on the Spanish island of Mallorca, a region of high outbreak of infections with a new influenza A/H1N1 virus. Symptomatic influenza A infection, but not H1N1 positive, led to myocarditis after intimate contact with a woman with positive H1N1 titer

http://www.ncbi.nlm.nih.gov/pubmed/21769827

19) Recurrent Congestive Heart Failure in a Child Due to Probable Myocarditis.
Pediatr Cardiol. 2011 Sep 11.
Lee AF, Chiasson DA, Smythe JF, Sanatani S.
Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, V6T 2B5, Canada.
Recurrent congestive heart failure (CHF) attributable to myocarditis is a seldom-discussed entity in the scientific literature. This report describes the case of an 8-year-old girl who had three clinically identical episodes of CHF, beginning at the age of 5 years, with each episode preceded by a viral prodrome. The clinical features and the echocardiography and electrocardiogram findings were most supportive of myocarditis. Symptoms and investigations completely normalized between episodes. The third episode, associated with influenza A (strain H1N1) infection, led to cardiac arrest and death on day 2 after admission.

http://www.ncbi.nlm.nih.gov/pubmed/21910020

20) Acute myocarditis mimicking acute myocardial infarction associated with pandemic 2009 (H1N1) influenza A virus.
Cardiol J. 2011;18(5):552-5.
Erden I, Erden EC, Ozhan H, Basar C.
Here, we present the first known report of acute myocarditis mimicking acute myocardial infarction associated with the pandemic influenza A virus (H1N1) infection.

http://www.ncbi.nlm.nih.gov/pubmed/21947992

21) Acute fulminant myocarditis and the 2009 pandemic influenza A virus (H1N1).
West Indian Med J. 2011 Mar;60(2):217-9.
Adedayo O, Iheonunekwu N, Jefferson D.
We present a case of severe disease with acute heart failure and arrhythmia due to fulminant myocarditis in a 50- year old obese man with diabetes mellitus.

http://www.ncbi.nlm.nih.gov/pubmed/21942131

22) Successful Treatment of Novel H1N1 Influenza related Fulminant Myocarditis with Extracorporeal Life Support.
J Cardiothorac Surg. 2011 Dec 20;6(1):164.
Mohite P, Popov AF, Bartsch A, Dhar D, Zych B, Moza A, Krueger H, Simon AR.
An 18 year old previously fit and well female suffered from lethargy and malaise for six weeks combined with rigors, fever, nausea, vomiting and diarrhea over four days. After collapsing on train, she was admitted to local hospital where she was diagnosed of cardiogenic shock with echocardiogram showing severely impaired left ventricular function with ejection fraction of 20%
Viral PCR (Polymerase Chain Reaction) test detected Influenza A RNA in nasal and throat secretions of the patient confirming H1N1 Pandemic strain a week after the admission and she was started on OD 5mg Oseltamivir.
http://www.cardiothoracicsurgery.org...8090-6-164.pdf

23) A case of fulminant myocarditis associated with novel N1H1 influenza successfully treated by percutaneous cardiopulmonary support system
Journal of Cardiology Cases
Volume 2, Issue 2, October 2010, Pages e106-e110
doi:10.1016/j.jccase.2010.05.004
Ryota Morimoto MDa, Corresponding Author Contact Information, E-mail The Corresponding Author, Takahito Sone MD, FJCCa, Hideyuki Tsuboi MDa, Hiroaki Mukawa MDa, Itsuro Morishima MDa, Michitaka Uesugi MDa, Hiromi Sasaki MDa, Toru Niwa MDa, Yuusuke Izumi MDa, Toshihiko Yamamoto MDa, Kei Ichihashi MDa, Yasunori Kanzaki MDa, Hiroaki Nagai MDa, Yosuke Iwata MDb
Purchase
a Department of Cardiology, Ogaki Municipal Hospital, 4-86 Minaminokawa-cho, Ogaki 503-0864, Japan
b Department of Pathology, Ogaki Municipal Hospital, Ogaki, Japan

We report a case of fulminant myocarditis associated with N1H1 influenza virus infection. N1H1 was confirmed by a polymerase chain reaction assay and she was treated with oseltamivir phosphate. She was admitted to the hospital because of respiratory distress, however, echocardiography revealed severely depressed wall motion followed by refractory ventricular fibrillation. Extracorporeal circulation by emergent percutaneous cardiopulmonary support system was required to maintain hemodynamic stability. Cardiac function was spontaneously and gradually restored within a week. Findings from biopsy samples taken on day 1 and day 23 were consistent with acute myocarditis.
http://www.sciencedirect.com/science...78540910000356

24) Pandemic (H1N1) 2009–associated Deaths Detected by Unexplained Death and Medical Examiner Surveillance
Emerging Infectious Diseases

During the pandemic (H1N1) 2009 outbreak, Minnesota, New Mexico, and Oregon used several surveillance methods to detect associated deaths. Surveillance using unexplained death and medical examiner data allowed for detection of 34 (18%) pandemic (H1N1) 2009–associated deaths that were not detected by hospital-based surveillance.
Two previously healthy children with nasopharyngeal swabs positive for influenza had evidence at autopsy of viral myocarditis.

http://wwwnc.cdc.gov/eid/article/17/...article.htm#r1

25) Aborted sudden cardiac sudden death associated with influenza A(H1N1) infection
European Heart Journal
Theofilos M. Kolettis, University of Joannina, Greece

We would like to share our recent experience with influenza A (H1N1)-related myocarditis in a young man, presenting with out-of-hospital cardiac arrest. A previously healthy 27-year-old male had cardiac arrest at his home. The patient had a 2-day history of malaise, cough and fever for 2 days prior to clinical presentation. Basic cardiopulmonary resuscitation was initiated promptly and ventricular fibrillation was recorded by the emergency medical services after approximately 10 minutes. He was successfully defibrillated, intubated and mechanically ventilated.
Transthoracic echocardiography revealed moderately reduced left ventricular function with diffuse hypokinesis and ejection fraction of 40%
http://eurheartj.oxfordjournals.org/...32/3/283/reply

26) Influenza A(H1N1) infection and severe cardiac dysfunction in adults: A case series.

Wien Klin Wochenschr. DOI: 10.1007/s00508-010-1520-0
Wiegand JA, Torgersen C, Bloechlinger S, Takala J, D&#195;&#188;nser MW.
Department of Intensive Care Medicine, Inselspital Bern, Bern, Switzerland.

This case series summarizes the disease course of four patients with 2009 influenza A(H1N1) infection who were treated at our institution from November 2009 until September 2010. All patients presented with severe cardiac dysfunction (acute heart failure, cardiogenic shock or cardiac arrest due to ventricular fibrillation) as the leading symptom of influenza A(H1N1) infection. Two patients most likely had pre-existent cardiac pathologies, and three required catecholamine therapy to maintain hemodynamic function. Except for one patient who died before influenza A(H1N1) infection had been diagnosed, all patients received antiviral therapy with oseltamivir and supportive critical care. Acute respiratory distress syndrome due to influenza A(H1N1) infection developed in one patient. Heart function normalized in two of the three surviving patients but remained impaired in the other one at hospital discharge.

http://www.springerlink.com/content/634240x64v8153r2/

27) Fulminant myopericarditis in an immunocompetent adult due to pandemic 2009 (H1N1) influenza A virus infection.

Scand J Infect Dis.

Davoudi AR, Maleki AR, Beykmohammadi AR, Tayebi A.
Department of Infectious Disease, Mazandaran University of Medical Sciences, North Iranian Research Centre for Infectious Disease , Sari.

Here we report a case of fulminant myopericarditis presenting with acute heart failure and a state of shock in a previously healthy young woman. H1N1 influenza A virus sequences were identified in throat and pericardial fluid, suggesting a viral source of the infection.

http://www.ncbi.nlm.nih.gov/pubmed/22074554

28) Epidemiologic and clinical parameters in hospitalized patients with novel Influenza A (H1N1) in Taranto province, Italy
Infez Med. 2010 Jun 1;18(2):104-107

Buccoliero G, Romanelli C, Lonero G, Loperfido P, Chimienti A, Resta F.

Our study aimed to describe the epidemiologic and clinical parameters of hospitalized patients during the pandemic. Fifty-one persons with suspected influenza A H1N1 were hospitalized.
One patient died of a concomitant myopericarditis.

http://www.ncbi.nlm.nih.gov/pubmed/20610932

29) Cardiac tamponade and heart failure due to myopericarditis as a presentation of infection with the pandemic H1N1 2009 influenza A virus.
J Clin Microbiol. 2010 Apr 14.
Puzelli S, Buonaguro FM, et al. the Campania H1N1 Task Force.

We describe a fatal case of myopericarditis presenting with cardiac tamponade in a previously healthy 11 years old child. Pandemic H1N1 2009 influenza A virus sequences were identified in throat, myocardial tissues and pericardial fluid, suggesting a damage of myocardial cells directly caused by the virus.

http://jcm.asm.org/content/48/6/2298.abstract

30) Pathology of the swine-origin influenza A (H1N1) flu.
Pathol Res Pract. 2010 Dec 19.
Calore EE, Uip DE, Perez NM.
Pathology Department, Em&#237;lio Ribas Infectology Institute, Sao Paulo, Brazil; Intensive Care Unit, Mandaqui Hospital, Sao Paulo, S&#227;o Paulo State, Brazil.

Focal myocarditis was observed in one case.

31) Constrictive Pericarditis Accompanied by Swine-Origin Influenza A (H1N1) Infection.
Korean Circ J. 2010 Oct;40(10):539-542. Epub 2010 Oct 31.
Jang JY, Chang HJ, Jang Y, Han SH, Bang WD, Cho SS, Oh CM, Yu HT, Shim CY, Ha JW, Chung N.
Department of Cardiology, Cardiovascular Hospital, Severance Hospital, Yonsei University Health System, Seoul, Korea.

We report a case of acute constrictive pericarditis in a healthy subject infected by the swine-origin influenza A (H1N1) virus.

http://www.ncbi.nlm.nih.gov/pubmed/21088760

32) Research Hospitalised adult patients with pandemic (H1N1) 2009 influenza in Melbourne, Australia
The Medical Journal of Australia
MJA 2010; 192 (2): 84-86
Justin T Denholm, Claire L Gordon, Paul D Johnson, Saliya S Hewagama, Rhonda L Stuart, Craig Aboltins, Cameron Jeremiah, James Knox, Garry P Lane, Adrian R Tramontana, Monica A Slavin, Thomas R Schulz, Michael Richards, Chris J Birch and Allen C Cheng




these included some unusual complications, such as febrile seizures (three patients), rhabdomyolysis (one), myocarditis (one) and Guillain–Barr&#233; syndrome (one). Other non-respiratory presentations included preterm labour, syncope, lethargy, abdominal pain and diarrhoea.

http://www.mja.com.au/public/issues/...n10902_fm.html

33) Clinical characteristics of patients with infection due to Influenza A (H1N1) 2009 and critical pathology
An Pediatr (Barc). 2011 Feb;74(2):97-102

P&#233;rez Navero JL, Rumbao Aguirre J, Correas S&#225;nchez A, Salda&#241;a Garc&#237;a N, Mu&#241;oz-Villanueva MC, Ibarra de la Rosa I.
Intensivos Pedi&#225;tricos, Unidad de Gesti&#243;n Cl&#237;nica de Pediatr&#237;a y sus Especialidades, Hospital Universitario Reina Sofia, C&#243;rdoba, Spain.
One patient developed fulminant myocarditis and required ECMO (Extracorporeal Membrane Oxygenation) because of secondary cardiogenic shock, which developed into multiple organ dysfunction and brain death

http://www.ncbi.nlm.nih.gov/pubmed/21195686

34) Acute myocarditits in H1N1 influenza A virus infection
Rev Assoc Med Bras. 2010 Jul-Aug;56(4):394
Calderaro D, dos Santos Sde S, Tonacio AC, Gualandro DM, Rezende PC, Yu PC, Caramelli B, Ho YL.
Interdisciplinary Medicine in Cardiology, Heart Institute (InCor), and Division of Infectious and Parasitic Diseases, Hospital das Cl&#237;nicas, University of S&#227;o Paulo School of Medicine, S&#227;o Paulo, SP.
A 28 year-old man, previously healthy, was admitted to the emergency room with nine days of abdominal pain, myalgia, and headache. Two days after these initial symptoms, he developed high fever, cough and dyspnea.
H1N1 influenza A virus was detected on a nasopharyngeal swab using RT-PCR. On the 4th ICU day, after significant reduction of vasopressors, the patient had paroxysms of acute atrial fibrillation and hemodynamic deterioration. Soon after, the electrocardiogram (EKG) showed diffuse ST-segment elevation and the echocardiography (ECHO) disclosed mild left ventricular enlargement and hypocontractility of apical and medial segments in the septal, inferior, posterior and anterior wall. Left ventricular ejection fraction was 48% (normal range above 55%).The patient's condition slowly improved, renal function recovered and he was successfully weaned from mechanical ventilation. He was discharged from hospital without cardiac sequelae.

http://www.scielo.br/scielo.php?scri...lng=en&nrm=iso




35) Fulminant pH1N1-09 influenza-associated myocarditis in pediatric patients
Pediatr Crit Care Med. 2011 Mar;12(2):e99-e101

Gross ER, Gander JW, Reichstein A, Cowles RA, Stolar CJ, Middlesworth W.
Division of Pediatric Surgery, Morgan Stanley Children's Hospital, New York-Presbyterian, New York, NY, USA. eg2561columbia.edu

In this report we describe two children with confirmed pH1N1-09 influenza infection that required intensive care for fulminant myocarditis. Neither patient had the typical symptoms of influenza-like illness, respiratory compromise, or evidence of pulmonary involvement. One child required extracorporeal membrane oxygenation. Both children survived to hospital discharge.
pH1N1-09 influenza infection can cause fulminant myocarditis in the healthy pediatric population. The clinical presentation may be nonspecific, and the lack of pulmonary symptoms may make diagnosis difficult. Extracorporeal membrane oxygenation support may offer an effective bridge to the recovery of heart function.

http://www.ncbi.nlm.nih.gov/pubmed/20601924

36) Fulminant myocarditis due to H1N1 influenza
Circ Heart Fail. 2010 May;3(3):e7-9
Al-Amoodi M, Rao K, Rao S, Brewer JH, Magalski A, Chhatriwalla AK.Mid America Heart Institute, Saint Luke's Hospital, 4300 Wornall Road, Kansas City, MO 64111, USA.

We report 2 cases of fulminant myocarditis caused by the H1N1 strain of influenza. As the incidence of H1N1 influenza infection continues to rise, physicians should be aware of this rare and potentially fatal complication because early diagnosis and aggressive supportive measures are imperative.


http://circheartfailure.ahajournals....nt/3/3/e7.full

37) Fatal acute myocarditis and fulminant hepatic failure in an infant with pandemic human influenza A, H1N1 (2009) virus infection
Journal of Advanced Research,
H.F., El-Shabrawi , Hafez M., Bazaraa , Hanan, Zekri , Hanaa I., RadyWe
Department of Pediatrics, Cairo University, Egypt

report the clinical presentation of a 10month-old infant who succumbed with acute myocarditis and fulminant hepatic failure associated with a virologically confirmed human influenza A, H1N1 (2009) virus infection. To date, this is the first pediatric patient presenting with this fatal combination of complications during the current H1N1 pandemic. Therefore, we recommend meticulous assessment and follow up of the cardiac status, liver enzymes and coagulation profile in all pediatric patients with severe H1N1 influenza infection.

http://www.sciencedirect.com/science...9012321100004X

38) Cardiac Conduction System Affection in a Case of Swine
Flu
J Assoc Physicians India.
Gokhroo RK, Barjaty HD, Bhawna K.
Department of Cardiology, J.L.N. Medical College, Ajmer.

We present a case of swine flu presenting as bilateral pneumonia with involvement of cardiac conduction system in the form of increased PR interval and sinus bradycardia during the initial course of disease process.
A patient, 42 years old male, presented in the department
of cardiology as a case of accelerated hypertension with
shortness of breath and low grade fever for three days. Patient
had past history of hypertension with no documents available.



http://www.japi.org/january_2011/oa_...conduction.pdf

39) Successful management of fulminant influenza A subtype H1N1 myocarditis
BMJ Case Reports 2010; doi:10.1136/bcr.02.2010.2763
Miguel Cobas et al

The present report concerns an atypical manifestation of the disease in a previously healthy middle-aged patient who presented with severe, refractory cardiogenic shock 4 days after being diagnosed as having influenza A. The patient was considered for emergency heart transplant. Successful treatment involved the use of a left ventricular assist device, extracorporeal membrane oxygenation, intravenous immunoglobulin and peramivir as therapeutics and bridging therapies for transplant. This case is a report of H1N1 fulminant myocarditis and illustrates the usefulness of a multidisciplinary approach in the care of these patients.

http://casereports.bmj.com/content/2....2763.abstract

40) Surgical emergencies confounded by H1N1 influenza infection - a plea for concern
World Journal of Emergency Surgery 2010, 5:6
Person et al.

A healthy 19-year-old man fell from a 3-meter-long ladder and hit his head.
During the operation, due to a significant yet unexplained decrease in the blood
pressure the patient underwent an intraoperative transesophageal
echocardiography that demonstrated a severe global left ventricular dysfunction with an ejection fraction of 15%.
The diagnosis of H1N1 influenza was made 2 days after his admission by real time PCR testing, and he received intravenous immunoglobulin (IVIG) and Oseltamivir.
Despite aggressive attempts of resuscitation, the patient died 7 days from admission with a final diagnosis of viral myocarditis and pneumonitis related to H1N1 influenza

http://www.wjes.org/content/pdf/1749-7922-5-6.pdf

41) Report of two rare complications of pandemic influenza A (H1N1)
J Infect Dev Ctries. 2012 Feb 13;6(2):204-7
Babamahmoodi F, Davoodi AR, Ghasemian R, Delavarian L.

The second case, a 25-year-old pregnant woman with high fever, chills and severe fatigue and malaise, developed tachypnea, tachycardia, respiratory distress, cyanosis and loss of consciousness a few hours after admission. Echocardiography reported myopericarditis. The patient was transferred to the intensive care unit and mechanical ventilation was begun. The next day, the patient started vaginal bleeding which progressed to spontaneous abortion three days later. Diagnosis of novel influenza A (H1N1) was confirmed using real-time reverse-transcriptase PCR of a pharyngeal swab.

http://www.ncbi.nlm.nih.gov/pubmed/22337853

42) 2009 H1N1 Fatalities: The New Mexico Experience
J Forensic Sci 2012 May 9. doi: 10.1111/j.1556-4029.2012.02163.x.
Brooks EG, Bryce CH, Avery C, Smelser C, Thompson D, Nolte KB.

We retrospectively reviewed medical records of all New Mexico 2009 pandemic influenza A (pH1N1) fatalities (n = 50)....Two cases had significant extra-pulmonary manifestations: myocarditis and cerebral edema with herniation.

http://onlinelibrary.wiley.com/doi/1...163.x/abstract

43) Fulminant myocarditis associated with pandemic H1N1 influenza A virus
Rev Port Cardiol. 2012 Jun 15
Cabral M, Brito MJ, Conde M, Oliveira M, Ferreira GC.
Department of Pediatrics, Hospital Dona Estef&#226;nia - CHLC - EPE, Lisbon, Portugal.

We describe a previously healthy 10-year-old boy, with a three-day history of flu-like symptoms without antiviral treatment. He was hospitalized with dehydration and hypothermia in the context of persistent vomiting, when he suddenly developed heart failure secondary to fulminant myocarditis. Despite aggressive management, including circulatory support and cardiopulmonary resuscitation measures, the patient died of cardiogenic shock. The postmortem histopathology was compatible with a multisystem viral infection with myocarditis and pulmonary involvement, and H1N1v polymerase chain reaction was positive.

http://www.ncbi.nlm.nih.gov/pubmed/22704822

44) Myocarditis in a pediatric case of pandemic 2009H1N1 influenza
Pediatr Int. 2012 Aug;54(4):558-62. doi: 10.1111/j.1442-200X.2012.03592.x.
Jibiki T, Sakamoto R, Nakaya M, Kanazawa M, Gotoh F, Yamaguchi S, Kutsuna S, Hashimoto Y, Anzai S, Abe K.

We report a 6-year-old boy with no major disease history or allergic conditions initially presented with pneumonia, progressed to acute respiratory distress syndrome and acute myocarditis caused by pandemic 2009H1N1 influenza diagnosed with RT-PCR testing, successfully managed with mechanical ventilation and percutaneous cardiopulmonary support system.

http://www.ncbi.nlm.nih.gov/pubmed/22830548

45) A Case Series of Reversible Acute Cardiomyopathy Associated with H1N1 Influenza Infection.
Barbandi M, Cordero-Reyes A, Orrego CM, Torre-Amione G, Seethamraju H, Estep J.
PMID:22891110 PMCID:PMC3405785

The cases above describe Influenza A (H1N1) infection complicated by acute myocardial dysfunction in [three] patients with no prior history of heart failure. Though viral infections have been associated with cardiotoxicity, only a few reports have linked the Influenza A (H1N1) subtype to myocarditis or acute myocardial dysfunction.4, 5 In our case series, all patients had multiple risk factors for developing complicated influenza infection (2 of the 3 patients had chronic underlying lung disease), but none of them had acute ischemic events or a persistent primary rhythm disturbance detected by EK G or telemetry to explain the acute deterioration in myocardial function. The documented compromise in cardiac systolic function with the acute viral syndrome, and the subsequent recovery of myocardial function after resolution of the viral illness, supports the concept that H1N1 influenza is the cause of acquired myocarditis.

http://www.methodisthealth.com/publi...DCVJ12_8-1.pdf

46) A Case of Fatal Fulminant Myocarditis Presenting as an Acute ST-Segment Elevation Myocardial Infarction and Persistent Ventricular Tachyarrhythmia Associated with Influenza A (H1N1) Virus in a Previously Healthy Pregnant Woman.
Ona MA, Bashari DR, Tharayil Z, Charlot A, Hoskins I, Timoney M, Usmani S, Royzman R.
Cardiology. 2012 Sep 27;123(2):103-107.

We report the first fatal case of fulminant myocarditis presenting as an acute ST-segment elevation myocardial infarction and ventricular tachyarrhythmia associated with influenza A (H1N1) in a previously healthy pregnant woman. A 38-year-old Asian woman, gravida 3, para 1-0-1-1, presented with flu-like symptoms. Initially, she developed wide-complex tachycardia requiring several defibrillations and was later intubated. Electrocardiogram showed ST-segment elevation. Coronary angiogram was negative and a pulmonary angiogram ruled out pulmonary embolism. Fetal compromise was noted on the monitor, and the patient underwent an emergent cesarean section. She subsequently expired. Autopsy confirmed severe myocarditis. Further testing confirmed influenza A (H1N1) virus.

http://www.ncbi.nlm.nih.gov/pubmed/23018755

47) Levosimendan in a case of severe peri-myocarditis associated with influenza A/H1N1 virus.
Busani S, Pasetto A, Ligabue G, Malavasi V, Lugli R, Girardis M.
Br J Anaesth. 2012 Dec;109(6):1011-3. doi: 10.1093/bja/aes413

Editor—Pandemic influenza A/H1N1 spread worldwide in 2009–2010, but several new cases have been identified in 2011 in Italy. Respiratory failure requiring mechanical ventilation was the hallmark described during the influenza A/H1N1 pandemic and the patients with myocarditis were rare.1,2 We report the case of a fulminant peri-myocarditis associated with influenza A/H1N1 virus that was successfully managed with levosimendan.

A 54-yr-old female with case history of mild hypothyroidism developed flu with fever, cough, and weakness. Two days later, the fever disappeared but she was brought to the emergency department (ED) of our hospital because of severe constrictive thoracic pain and fainting. At ED admission, the patient was drowsy and hypotensive despite fluid infusion (crystalloids 1.5 litre). Electrocardiography showed sinus tachycardia, low-voltage QRS with inferior and septal ST elevation; cardiac troponin I (Tn) was 1.4 ng ml−1 and …

http://bja.oxfordjournals.org/conten...6/1011.extract

48) Influenza A/H1N1 (2009) Infection as a Cause of Unexpected Out-of-Hospital Death in the Young
Camille Boulagnon ,, Nicolas Leveque,Fanny Renois,Laurent Andreoletti, Paul Fornes
Journal of Forensic Sciences DOI: 10.1111/j.1556-4029.2012.02180.x

Case history: we report on an unexpected out-of-hospital death involving a young male with no past medical history and no vaccination. Fever was his only symptom. Laboratory tests: histology showed patchy necrotic foci with mononuclear inflammation in the lungs. The heart was histologically normal, but virological analyses using molecular biology on frozen myocardial samples showed high virus load. In conclusion, this case report shows that influenza A/H1N1 (2009) virus can be a cause of sudden cardiac death in the young and demonstrates the importance of quantitative virological analyses for the diagnosis of myocarditis.

http://onlinelibrary.wiley.com/doi/1...180.x/abstract

49) Pandemic influenza in the 2009/2010 season in central Poland: The surveillance study of laboratory confirmed cases
Kuchar E, Nitsch-Osuch A, Karpinska T, Kurpas D, Zycinska K, Wardyn K, Szenborn L.
Respir Physiol Neurobiol. 2013 Jun 1;187(1):94-8. doi: 10.1016/j.resp.2013.02.013

Four hundred and eighty four people were hospitalized, including 142 children under 14. Thirty two patients died, all with pre-existing risk factors. The most common complications were pneumonia, cardiac arrest, septic shock, circulatory insufficiency, multi-organ failure and myocarditis. The majority of patients (388/484) were treated with oseltamivir. Fifty three patients were mechanically ventilated, 52 patients were given oxygen. Only 11 out of the 561 patients were immunized against seasonal influenza. In conclusion, pandemic influenza affects all age groups, but it is more common in younger patients. Pandemic influenza is becoming an emerging health risk for the Polish population.

http://www.sciencedirect.com/science...6990481300044X

50) Fulminant Myocarditis Associated With H1n1 Virus: Case Report and Literature Review
Saraiva, M.1; Taguchi, A.2; Gaspar, H.A.1; Ferranti, J.F.1; Carvalho, W.B.1; Delgado, A.F.
Pediatric Critical Care Medicine: May 2014 - Volume 15 - Issue 4_suppl - p 187 doi:10.1097/01.pcc.0000449565.64468.2f

Reporting the case of one 4 years old patient, with cardiogenic shock and polymerase chain reaction positive to Influenza H1N1 virus and discussed about the clinical findings, laboratory tests, imaging and pathological examinations.
Results: This patient had severe fulminant myocarditis evolution, with hemodynamic instability and no response to the clinical treatment despite the early diagnosis.
Conclusions: The H1N1 virus should always be regarded as one of the causes of myocarditis and relevant characteristics such as seasonality, endemic situation and vaccine coverage should be considered. Despite intensive treatment the mortality of fulminant myocarditis is high. Mechanical circulatory support using extracorporeal membrane oxygenation (ECMO) in patients with rapidly progressive heart failure and cardiogenic shock unresponsive to medical treatment seems to reduce significantly this mortality.

http://journals.lww.com/pccmjournal/...iated.836.aspx


51) A Fatal Case of Acute Myocardial Infarction following the Improvement of Influenza A(H1N1)pdm2009-related Acute Myocarditis
Iwanaga N, Nakamura S, Fukuda Y, Takazono T, Imamura Y, Izumikawa K, Yanagihara K, Soda H, Tashiro T, Kohno S. Internal Medicine Vol. 53 (2014) No. 18 p. 2153-2157

A 52-year-old Indian man was hospitalized due to dyspnea and a high fever caused by influenza A(H1N1)pdm2009. Elevated cardiac enzymes, a chest X-ray showing bilateral infiltrative shadows, cardiomegaly and pleural effusion and echocardiography indicating diffuse hypokinesis of the left ventricle suggested cardiac failure due to acute myocarditis. Owing to the administration of combined modality therapy, including steroids and intravenous γ-globulin, the patient's clinical symptoms of influenza completely resolved. However, he suddenly complained of epigastric pain due to acute myocardial infarction and died. This report is an educational case, the results of which suggest that greater attention should be paid to the potential for myocardial infarction even after an influenza virus infection is found to improve.

https://www.jstage.jst.go.jp/article....2435/_article

52) Fulminant myocarditis associated with the H1N1 influenza virus: case report and literature review
Maria L&#250;cia Saraiva Lobo, &#194;ngela Taguchi, Helo&#237;sa Amaral Gaspar, Juliana Ferreira Ferranti, Werther Brunow de Carvalho, Artur Figueiredo Delgado Rev. bras. ter. intensiva vol.26 no.3 S&#227;o Paulo July/Sept. 2014

Female patient, 4 years and 8 months old, previously healthy and with normal weight, without prior vaccination for influenza virus. History of cough and rhinorrhea in the last two weeks, with unmeasured fever. Two days prior, she presented with abdominal pain, vomiting and poor general condition.
She was admitted to the emergency room in poor general condition, severely dehydrated, normotensive, moaning, tachypneic and tachycardic (Table 1). Initially diagnosed with septic shock, she received fluid resuscitation with 70mL/kg crystalloid, oxygen therapy and empiric antibiotic therapy (ceftriaxone 100mg/kg/day). Laboratory tests showed anemia, metabolic acidosis and elevated C-reactive protein concentration (Table 2). Still in the emergency room, the patient evolved with worsening of the tachydyspnea, hypotension and moaning, in addition to hepatomegaly, anasarca and presence of heart murmur. Electrocardiogram showed sinus tachycardia (155 beats per minute), and chest X-ray showed an enlarged cardiac area, mild right pleural effusion and diffuse pulmonary infiltrates, suggesting alveolar congestion (Figure 1). At that moment, a diagnosis of congestive heart failure secondary to myocarditis or cardiomyopathy associated with sepsis was established.
Laboratory tests showed elevated myocardial necrosis and inflammatory markers (Table 1). All cultures remained negative, and C-reactive protein (CRP) was positive for H1N1. Despite clinical treatment, the patient did not show improvement of her hemodynamic profile, staying in refractory shock. After the introduction of adrenaline and an increase of the dose of the other vasoactive drugs, the patient showed no clinical improvement. The patient died 48 hours after ICU admission.

http://www.scielo.br/scielo.php?scri...rm=iso&tlng=en


53) Influenza A H1N1 pdm09-associated myocarditis during zanamivir therapy

Ito N¹, Sato M¹, Momoi N¹, Aoyagi Y¹, Endo K¹, Chishiki M¹, Kawasaki Y¹, Hosoya M¹.
Pediatr Int. 2015 Oct 20. doi: 10.1111/ped.12712.

A 9-year-old girl developed influenza A H1N1 pdm09-associated myocarditis and pericarditis 2 days after starting zanamivir therapy. The virus was detected in the respiratory tract but not in the serum or pericardial effusion. The virus sampled from the respiratory tract had normal susceptibility to neuraminidase inhibitors. Although no differences in interferon-γ, interleukin (IL)-1β, and tumor necrosis factor-α were observed between the plasma and pericardial effusion, some inflammatory cytokines or chemokines (IL-6 and IL-8) and vascular endothelial growth factor were remarkably elevated in the pericardial effusion compared with the plasma. This suggested that the influenza virus, after infecting the respiratory tract, affected the myocardium, causing myocarditis to gradually develop, which might have been followed by an autoreactive pericarditis causing increased pericardial effusion. Therefore, influenza-associated myocarditis should be considered when influenza patients have respiratory and cardiac involvement, even during treatment with a neuraminidase inhibitor.

http://www.ncbi.nlm.nih.gov/pubmed/26482326

54) Influenza H1N1 Infection Leading To Cardiac Tamponade in a Previously Healthy Patient: A Case Report

Research in Cardiovascular Medicine. 5(3): e31546


INTRODUCTION:

The cardiac manifestations of influenza A are broad, ranging from self-limited pericarditis to fatal cardiomyopathy. The 2009 H1N1 influenza A (H1N1) strain is a rare cause of pericarditis, and its role in developing a pericardial effusion leading to tamponade has infrequently been reported.
CASE PRESENTATION:

We describe a case of a young female with no prior cardiovascular history who presents with a pericardial effusion and shock secondary to cardiac tamponade from pericarditis due to H1N1 influenza A.
CONCLUSIONS:

This case highlights the potential severity of H1N1 infections and the utility of considering cardiac tamponade in patients presenting with influenza symptoms and circulatory collapse.

http://cardiovascmed.com/68860.pdf

Other sources

1)In Germany, there had been at least three cases of fatal H1N1 infections in children and young adults with acute myocarditis as the cause of death (autopsy findings).

German-docter on flutrackers.com

http://www.flutrackers.com/forum/sho...ht=myocarditis

2)South Korean actress gets H1N1 coming back from Rome, dies
due to complications caused by H1N1 influenza, died on the 11th of this month, only 37 years old. Liu Dongshu end of last month went to Italy, after Rome International Film Festival flu symptoms after returning home, hospital treatment, passed away just over a week.
still 9 days in the hospital is 11th of this month due to H1N1 influenza-induced myocarditis and died

http://news.sina.com.tw/article/20101116/3969101.html

3)Samrat Pandya, the 31–year–old resident of Gurgaon (India) who died on Thursday following two cardiac arrests, was diagnosed with myocarditis after an ECG was conducted. A central team that returned from Pune also reported deaths there due to Myocarditis.

http://pune.aarogya.com/index.php/in...150&Itemid=158

4)SPETALING JAYA (Aug 2, 2009): Malaysia registered its fifth and sixth Influenza A (H1N1) deaths today. Both the victims are children, one in Perak and the other in Johor … an 11-year-old boy died in Hospital Sultanah Aminah at 8.30am on Saturday
"The boy's condition worsened while under treatment and was referred to the Intensive Care Unit (ICU) the following day. Tests showed he had lung infection and myocarditis and was confirmed positive of A(H1N1) at 11am on Saturday

http://www.flutrackers.com/forum/sho...d.php?p=275090

5) Giorgia Casoli, 2 years, dead at Reggio Emilia the 7-02 -2013. The girl had slight symptoms of ILI from a few days, not visited. She was found dead in her bed. The diagnosis, communicated from the primary of paediatrics was myocarditis from the H1N1 virus

http://gazzettadireggio.gelocal.it/c...aese-1.6497624


6) UDINE. In coma for guilt of influenza. Critical are the conditions of a woman of 39 years from Friuli arrived to the emergency department at the Hospital Santa Maria della Misericordia in Udine with a serious heart localization of the H1N1 virus, a variant of influenza derived from pigs, the so-called "swine", i.e. one of the three viruses that are dominating the current flu season. The shelter, located in conditions of extreme urgency, dates back to almost a month ago, but the woman is still in serious condition and remains in the intensive care unit, where he has never taken up the senses. Just arrived at the Santa Maria della Misericordia doctors had diagnosed a infectious localization to the myocardium, the contractile part of the heart, which responded less well than expected, causing further complications, in the first place, a dangerous form of hyperperfusion injury, or a decrease in the inflow of blood to the tissues. It must be said that the patient had no other health problems, nor suffered from chronic diseases, which makes it all the more incomprehensible the case on which the doctors were reserved the prognosis.

http://messaggeroveneto.gelocal.it/c...coma-1.8764088

[tetano]

Re: Myocarditis and influenza A H1N1: a review of the literature

This is an open thread. The contribution of other members will be appreciated.

[tetano]

Re: Myocarditis and influenza A H1N1: a review of the literature

I added the last article published on the Journal of Infectious Diseases about the autopsy study involving influenza B infections, which show a frequent evidence of cardiac damage and of myocarditis.

[tetano]

Re: Myocarditis and influenza A H1N1: a review of the literature

If it is true and confirmed by many studies the link between flu and myocarditis, not minor literature exists on the role of influenza as a trigger of acute myocardial infarction, especially in the elderly. It is opinion widely shared that approximately 50&#37; of deaths due to influenza occurs as a result of ischemic cardiac events.
Warren-Gash published a meta-analysis in which are reported 39 studies showing a significant association between influenza and myocardial infarction, although the protective effect of vaccination is not
demonstrated (Influenza as a trigger for acute myocardial infarction or death from cardiovascular disease: a systematic review, The Lancet Infectious Diseases )


In this article we find the case of an acute myocardial infarction in a healthy patient specifically associated with the novel viral infection.

Acta Cardiol. 2011 Dec;66(6):807-10.
H1N1 virus infection associated with acute myocardial infarction in a young patient without coronary artery disease--first reported case.
Arbit B, Gaultier CR, Schwarz ER.
Cedars-Sinai Heart Institute, Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.

http://www.ncbi.nlm.nih.gov/pubmed/22299395

[tetano]

Re: Myocarditis and influenza A H1N1: a review of the literature

A very recommended article on myocarditis and influenza AH1N1-09:

Influenza Research and Treatment
Volume 2012 (2012), Article ID 351979, 8 pages
doi:10.1155/2012/351979
Myocarditis Associated with Influenza A H1N1pdm2009
Akira Ukimura,1 Hidetoshi Satomi,1 Yukimasa Ooi,1 and Yumiko Kanzaki21Department of General Internal Medicine, Osaka Medical College, Takatsuki 569-8686, Japan
2Third Department of Internal Medicine, Osaka Medical College, Takatsuki 569-8686, JapanReceived 14 June 2012; Revised 28 October 2012; Accepted 15 November 2012Academic Editor: Daniel R. Perez

Abstract

Acute myocarditis is a well-known complication of influenza infection. The frequency of myocardial involvement in influenza infection varies widely, with the clinical severity ranging from asymptomatic to fulminant varieties. The worst cases can result in death due to impaired cardiac function, although such fulminant myocarditis associated with influenza infection is rare, as shown by previous papers. Following the 2009 influenza pandemic, we reported on the clinical features of a cohort of 15 patients in Japan with H1N1pdm2009 myocarditis. In our subsequent survey of the literature for case reports or series of patients with myocarditis associated with H1N1pdm2009, we identified 58 detailed cases. We discuss here the high prevalence of fulminant myocarditis (36/58, 62%) among patients reported to have myocarditis associated with H1N1pdm2009. Mechanical circulatory support was required in 17 of the patients with fulminant myocarditis, 13 of whom recovered. We stress the need for increased awareness of influenza-associated myocarditis; such knowledge will facilitate earlier diagnosis and treatment of this fatal complication during future influenza pandemics.

full article

http://www.hindawi.com/journals/irt/2012/351979/

[etudiant]

Thank you, tetano!
That is a fine piece of work. It has been unclear to me how people could be going about their day and then suddenly collapse, as we've seen in multiple videos.
This research provides a very relevant insight, the patient may be a dead man walking, with the virus destroying the heart, unknown to the victim.