Progression of Duchenne Cardiomyopathy Presenting with Chest Pain and Troponin Elevation.

Abstract

Improved neuromuscular and respiratory therapies have altered the natural history of Duchenne muscular dystrophy (DMD) such that the most common cause of mortality is progressive cardiomyopathy. Despite imaging evidence of progressive cardiomyopathy, troponin I (cTn) is not significantly elevated in asymptomatic DMD patients. We describe eight boys with DMD evaluated for acute chest pain (ACP) and found to have acute cTn elevation with depressed left ventricular ejection fraction (LVEF). Of our eight patients, five presented with a primary complaint of ACP, while three presented with secondary myocardial injury in the context of systemic illness requiring hospitalization. Electrocardiograms showed diffuse ST changes and mean peak cTn level was 44±15.4 ng/mL (reference range <0.03 ng/mL). cTn levels normalized with only supportive care. Cardiac magnetic resonance imaging (CMR) was performed during the event on all but one patient, demonstrating increased late gadolinium enhancement (LGE) from 12.4±11.4% to 36.5±10.3% with associated deterioration of LVEF from 61±4.4% to 47.6±6.6% which remained depressed on follow-up CMR study (49.1±7.8%). All viral studies were negative. Additional investigations varied among patients, but no causative findings were demonstrated. ACP with cTn elevation occurs in DMD boys and may be indicative of cardiomyopathy progression as evidenced by acute left ventricular dysfunction and development or progression of myocardial fibrosis. This clinical presentation is under recognized. These events may represent an important pathophysiological mechanism in cardiomyopathy progression.