Role of cardiac alpha-actinin 2 pathogenic variant in human myocardium mechanics

A 48-years old female with no prior cardiac history presented with out-of-hospital ventricular fibrillation arrest. Echocardiogram showed normal left ventricular ejection fraction, stage II diastolic dysfunction, elevated right ventricular systolic pressure, and abnormal global longitudinal strain at −13% consistent with early left ventricular systolic dysfunction. Cardiopulmonary testing showed reduced peak volume oxygen at 9.7 mL/kg/min (44% of predicted) and reduced anaerobic threshold at 7.0 mL/kg/min, indicating AHA functional class IV.