Fulminant Myocarditis: clinical profile, outcomes and comparison with myocardial infarction-related cardiogenic shock

Abstract Background Refractory cardiogenic shock due to fulminant myocarditis is a life-threatening condition often associated with multiorgan failure, which can be reversed using veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Objective To analyze the characteristics and clinical evolution of patients with fulminant myocarditis supported with VA-ECMO and compare them with patients experiencing acute pump failure due to myocardial infarction (excluding mechanical complications). Methods A prospective observational study was conducted on patients aged ≥18 years with refractory cardiogenic shock due to acute pump failure requiring VA-ECMO at a tertiary center from January 2020 to August 2025. Patients with myocarditis or myocardial infarction were included. Demographic data, clinical characteristics before ECMO implantation, and outcomes were analyzed. Results Among 68 patients supported with VA-ECMO for refractory cardiogenic shock, only 38 had an acute injury leading to severe pump failure: 12 with fulminant myocarditis and 26 after myocardial infarction. Among patients with fulminant myocarditis, two presented also with electrical storm, and one had a cardiac arrest before mechanical support. Right ventricular systolic dysfunction was observed in 11 patients, while moderate pericardial effusion was found in 2. Before ECMO implantation, 8 patients were classified as SCAI stage D and 10 as stage E. The median age was 40 years (IQR: 35-50.75), with 75% women and a median Charlson comorbidity index of 0 (IQR: 0-1.75). Compared to patients with myocardial infarction, the myocarditis group was significantly younger, had a higher proportion of women, and lower comorbidity burden. Shock severity was higher based on lactate levels and SOFA scores, but not VIS scores. Median VA-ECMO support duration was 6.5 days (IQR: 4.25-12.75), with no significant differences between groups. Right ventricular recovery was achieved in all myocarditis patients. During ECMO support, 4 myocarditis patients experienced ventricular tachycardia, and 1 developed complete atrioventricular block. Renal replacement therapy was required in only 2 patients. Severe complications included 2 ischemic strokes, 1 severe limb ischemia (in a patient who died), and 1 pulmonary embolism. ECMO weaning was successful in 11 patients, with only 1 death due to multiorgan failure. Inhospital mortality, 30-day and 1-year mortality was significantly lower in the myocarditis group. (Table 1). Conclusions Patients with fulminant myocarditis requiring VA-ECMO had significantly lower in-hospital and 30-day mortality rates compared to those with myocardial infarction-related cardiogenic shock. Despite higher initial severity, fulminant myocarditis was associated with better prognosis and higher survival rates.