When Lightning Strikes

efore the advent of endomyocardial biopsy in the 1960s, myocarditis was known as an uncommon cause of acute and fatal heart failure.Biopsy and later cardiac magnetic resonance imaging (MRI) revealed that myocarditis was both more common and less lethal than originally described.With greater use of imaging and biopsy, the clinical spectrum of myocarditis broadened to include milder presentations such as pericarditis with elevated troponin values, nonsustained ventricular arrhythmias, and occasionally heart block. 1 Patients who present with severe heart failure of <2-week symptom duration requiring parenteral inotropic or mechanical circulatory support are defined as having fulminant myocarditis.These relatively uncommon patients have a high risk in the near term of heart transplantation and death. 2 The cause of fulminant myocarditis historically was often an enteroviral (eg, Coxsackie virus) infection.As enterovirus prevalence has waned, new causes of fulminant myocarditis, including H1N1 influenza, 3 and drug-related eosinophilic myocarditis 4,5 have emerged.Fulminant myocarditis, as described by Lieberman et al 6 in 1991, was a clinical and a pathological entity.Clinically, all subjects had a distinct viral prodrome and severe hemodynamic compromise.Pathologically, all cases had an active inflammatory infiltrate of lymphocytes and macrophages with myocyte necrosis.No subjects with fulminant myocarditis in the original description had giant cell myocarditis.Lymphocytic myocarditis that presents with a distinct viral prodrome and severe hemodynamic compromise was later shown to paradoxically have a good long-term prognosis if patients survived the acute episode.Specific forms of myocarditis such as giant cell and necrotizing eosinophilic myocarditis that have a poor prognosis were not included in this or more recent reports with good long-term outcome.7 Ammirati et al 8 report in this issue a contemporary series of 187 patients with acute myocarditis.They observed that subjects with a fulminant presentation had a greater rate of in-hospital death or transplantation (25.5% versus 0%) and lower long-term survival (64.5% versus 100%) than patients with nonfulminant myocarditis.A subgroup analysis of fulminant and nonfulminant patients >15 years of age with <2 weeks of symptoms and biopsy-confirmed viral myocarditis had similar findings.Their observation of worse transplantation-free survival in fulminant myocarditis cohorts appears to contradict the earlier case series.Differences in patient cohorts and study designs may explain the divergent outcomes (Table ).For example, nonfulminant patients in the Ammirati et al series have a 100% survival at 9 years compared with 70% transplantation-free survival at 5 years in the McCarthy et al 7 series.The mean left ventricular ejection fraction was 55% in the nonfulminant patients in the Ammirati et al series (n=132).The mean cardiac output was only 4.6 L/m in the McCarthy et al series When Lightning Strikes Fulminant Myocarditis in the Realm of Inflammatory Cardiomyopathies