Ambulatory Monitoring and Arrhythmic Outcomes in Pediatric and Adolescent Patients With Duchenne Muscular Dystrophy

Abstract

Background Patients with Duchenne Muscular Dystrophy ( DMD ) develop cardiac fibrosis and dilated cardiomyopathy. We described the frequency of significant Holter findings in DMD , the relationship between cardiac function and arrhythmia burden, and the impact of these findings on clinical management. Methods and Results A retrospective review was done of patients with DMD who received a Holter from 2010 to 2014. Clinical and arrhythmic outcomes were analyzed. Patients were classified based on left ventricular ejection fraction ( LVEF ): ≥55%, 35% to 54% and <35%. Significant Holter findings included atrial tachycardia, ventricular tachycardia and atrial fibrillation/flutter. Logistic regression was used to assess predictors of significant Holter findings and change in care. The study included 442 Holters in 235 patients. Mean age was 14±4 years. Patients with cardiac dysfunction were older, and had increased late gadolinium enhancement and left ventricular dilation ( P <0.01). There were 3 deaths (1%), all with normal function and none cardiac. Patients with LVEF <35% had more arrhythmias including nonsustained atrial tachycardia ( P =0.01), frequent premature ventricular contractions, ventricular couplets/triplets, and nonsustained ventricular tachycardia ( P <0.001) compared to the other groups. LVEF <35% ( P <0.001) was the only predictor of clinically significant Holter finding. Four patients (40%) had change in medication in the LVEF <35% group compared to 9 (3%) in the ≥55% and 4 (4%) in the 35% to 54% groups ( P <0.001). Conclusions Sudden cardiac events are rare in DMD patients with an LVEF >35%. Significant Holter findings are rare in patients with DMD who have an LVEF >35%, and cardiac dysfunction appears to predict significant Holter findings. Holter monitoring is highest yield among DMD patients with cardiac dysfunction.