The Stokes-Adams syndrome is an abrupt, transient loss of consciousness due to a sudden but pronounced decrease in the cardiac output, which is caused by a paroxysmal shift in the mechanism of the heart beat. Most patients have complete heart block, with ventricular irritability or asystole during syncopal attacks, but both supraventricular and ventricular tachyarrhythmias without atrioventricular (A-V) block may be the responsible mechanism.