Fulminant Influenza A myocarditis in a patient presenting with cardiogenic shock and biventricular thrombi: a case report.

Background: Acute myocarditis is a common condition, with viral infections being the most common aetiology in North America and Europe. Influenza A myocarditis is however rare. As clinical manifestation may be fulminant, early recognition and management are paramount and may impact overall prognosis by hindering complications such as thromboembolism. A brief review of the literature, diagnostic modalities, work-up and treatment are discussed.

Case Summary: We present the case of a 42-year-old, previously healthy woman with recent flu-like symptoms, developing decompensated heart failure (HF) and cardiogenic shock within a week, due to Influenza A myocarditis. Biventricular thrombi were identified. Pharmacological haemodynamic support, followed by HF therapy, allowed full recuperation of heart function. Intracavitary thrombi disappeared under unfractionated heparin with bridging to rivaroxaban.

Discussion: Fulminant myocarditis due to Influenza A is rare and, to the best of our knowledge, has not been associated with intracardiac thrombi formation. Echocardiography is the essential first-line imaging modality. Cardiac magnetic resonance plays a major role in the diagnosis of myocarditis and may preclude the need for an endomyocardial biopsy in selected cases. Coronary angiography may be required to rule out ischaemic aetiology. First-line therapy in fulminant disease is pharmacological and, if required, mechanical haemodynamic support. Standard HF therapy complete the therapeutic options and should be introduced as soon as possible. Complications such as intracardiac thrombi formation, require targeted treatment. Specific drug therapies targeting Influenza A have no proven benefit in myocarditis.