Cardiac Electrical System Involvement in Alström Syndrome: Uncommon Causes of Dilated Cardiomyopathies

Alström syndrome is a rare autosomal recessive disorder with dilated cardiomyopathy in 60% of patients. Despite the frequency of cardiac involvement in Alström syndrome, conduction system abnormalities or arrhythmias have not been characterized previously. We report two siblings with Alström syndrome with conduction system involvement with left bundle branch block on electrocardiogram (ECG). One patient had first degree atrioventricular block in addition to bundle branch block and underwent pacemaker implantation. This same patient developed intra-atrial reentry tachycardia requiring anti-arrhythmic medication and eventual trans-catheter ablation. The second patient developed atrial and ventricular arrhythmias and underwent placement of a bi-ventricular defibrillator. These findings suggest that cardiac conduction system involvement and clinical arrhythmia may be significant yet under-recognized complications in patients with Alström syndrome. Patients should be routinely screened with ECG and Holter monitoring in addition to echocardiographic assessment and a cardiologist experienced with cardiomyopathy should be an integral part of the care team.