Cardiac involvement in the Kugelbert-Welander syndrome.

Two cases of the Kugelberg-Welander syndrome (juvenile form of progressive spinal muscular atrophy) associated with cardiomyopathy and cardiomegaly are presented. The first patient, a 24 year old man, had atrial flutter with complete atrioventricular (A-V) block due to A-H block. Echocardiography revealed an increase in the left atrial and right ventricular dimensions. The second patient was a 26 year old man whose electrocardiogram revealed an A-V junctional rhythm, deep Q wave in leads I, aVL and V5 to V6 and an RS pattern in lead V1. Histologic examination of the myocardium in Case 2 showed slight interstitial fibrosis. Review of previously reported cases shows that (1) the atrium, the ventricular myocardium and A-V conducting tissue may be involved, and (2) atrial arrhythmias, A-V conduction disturbances and congestive heart failure may occur in the Kugelberg-Welander syndrome.