Spectrum of sinus node dysfunction in two siblings

Two siblings, ages 14 and 23, with various features of sinus node dysfunction have been reported. Sinus bradycardia was the presenting feature in both patients. During the follow-up period both patients developed various types of ectopic rhythms which increased with exercise. One of them developed "silent atrium" at the age of 23 and had cerebral embolus as a complication. The other patient had frequent syncopal episodes and had to be treated with a combination of electronic pacemaker and antiarrhythmic drugs.