Influenza myocarditis complicated with atrioventricular block in a pregnant woman

Acute myocarditis is a well-recognized complication of influenza infection. The incidence of myocardial involvement in influenza infection is variable, and the clinical severity can range from asymptomatic to fulminant forms. Influenza infection can rarely be complicated by acute myocarditis leading to high-degree atrioventricular block and cardiogenic shock. We report a previously healthy pregnant woman, who initially presented with symptoms of influenza-like illness, later confirmed as influenza A infection. She developed hypotension shortly after admission that did not respond to fluid bolus and required inotropic support. On day 5, the electrocardiogram showed Mobitz I second-degree heart block, which later progressed to the third-degree heart block. Echocardiogram showed good cardiac contractility and minimal pericardial effusion while cardiac biomarkers were normal. A diagnosis of influenza myocarditis was made. She completed a course of oral oseltamivir and had temporary cardiac pacing performed, and subsequently recovered well.