Management of rhythm disorders in Duchenne muscular dystrophy: Is sudden death a cardiac or pulmonary problem?

Abstract

Dystrophin deficiency results in the cardiomyopathy of variable onset and deficiency. Myocardial scarring commonly results in cardiac dysfunction, with both atrial and ventricular dysrhythmias. Heart failure, rather than arrhythmia burden, remains the strongest cardiac predictor of mortality in this patient population. Current data suggest the overall rate of sudden cardiac death in pediatric dilated cardiomyopathy is significantly lower than in adults. Specifically, in the Duchenne cardiomyopathy population, sudden death from an arrhythmic cause appears to be rare, even in patients with previously diagnosed arrhythmias. Despite this, recommendations for implantable cardioverter‐defibrillator (ICD) placement in patients with Duchenne cardiomyopathy has traditionally been extrapolated from adult heart failure recommendations based on decreased left ventricular ejection fraction <35%. Early involvement of the cardiologist in the care for patients with dystrophin‐deficient cardiomyopathy is recommended for this reason. The indications for ICD placement to prevent sudden death in patients with Duchenne cardiomyopathy are not well defined. There is little evidence to suggest that placement meaningfully prolongs life in this population, and should be carefully considered in accordance with the care goals of the patient and his family.

Arrhythmias and cardiac MRI associations in patients with established cardiac dystrophinopathy

“…Heart failure and cardiomyopathies outwardly indistinguishable, can be due to diverse causes (ie: ventricular tachycardia/fibrillation, profound bradycardia/asystole, electromechanical dissociation ('pulseless electrical disease') or large pulmonary embolus). [52][53][54][55] A fundamental uncertainty, not resolved by this study, because no deaths or sustained ventricular arrhythmia episodes occurred, is whether the finding of infrequent, short arrhythmia episodes identifies an individual likely to benefit from prophylactic antiarrhythmic management or is only a marker of poor cardiac prognosis due mainly to progressive heart failure. 56 57 The links observed between increased arrhythmia burden, higher ECV, more extensive fibrosis and greater ventricular dilatation suggest that the occurrence of sustained arrhythmias reflects the presence of severe myocardial damage and dysfunction and so, increased risk of all-cause mortality rather than from arrhythmias preferentially.…”