Abstract 18850: A Report on Cardiomyopathy and Arrhythmia Incidence in a Duchenne Muscular Dystrophy Cohort

Abstract

Background: With improved respiratory care and the increasing lifespan of patients with Duchenne Muscular Dystrophy (DMD), morbidity and mortality due to cardiac involvement and sudden cardiac death (SCD) have increased. Nevertheless, data regarding incidence of SCD and the appropriate management of cardiac involvement are sparse; evidence-based guidelines for arrhythmia management in DMD do not exist. We sought to define the characteristics of electrocardiography, cardiac imaging abnormalities, association of therapeutic practices with cardiomyopathy and arrhythmia in a cohort with DMD. Methods and Results: A retrospective review of our current institutional electronic medical records (EMR) identified 125 DMD patients aged 10 or older. Electrocardiography was performed at least every 3 years or as prompted by symptoms. Symptom-prompted and baseline echocardiography, cardiac magnetic resonance (CMR) and Holter monitor data were extracted. Cardiac medical therapy primarily consisted of an angiotensin-converting-enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB; 98.4%) and beta-blockade (44.2%). As of May 2015, 115 of the 125 patients were living as determined by EMR. Left ventricular (LV) dysfunction was present in 52% of patients by age 18.7±5.9 years. Of 16 patients with LV dysfunction that underwent CMR, 13/16 had late gadolinium enhancement (LGE). Importantly, myocardial LGE was noted in 9 of 14 patients with normal LV function. The predominant ECG abnormality was tall R waves in V1, and Q waves in lateral precordial leads. Of 43 patients with Holter monitoring, 5 patients had non-sustained ventricular tachycardia and 5 had supraventricular tachycardia. Of 8 patients with an implantable cardioverter defibrillator (ICD), 1 died due to pulseless electrical activity. ICD placement was pursued in those with NSVT, persistently low EF or FS when patient preference allowed. Conclusions: ACEi or ARB use was universal in our DMD cohort. Evidence of LGE on CMR was noted in DMD patients with and without LV dysfunction. ECG characteristics did not appear to have a clinical impact. Future studies to examine the association of LGE and other clinical variables with SCD are warranted.