Adams-Stokes syndrome caused by sinoatrial block.

Forty-six patients with syncope and/or black-out episodes due to sinoatrial block are presented. Male-to- female ratio was i to i, and mean age at onset of symptoms approximately 63 years in both sexes. Additional heart disease, especially coronary artery disease, was frequently, but not constantly, found. Twenty-five per cent had sinus node dysfunction as the only manifestation of cardiac disease. Ninety per cent had frequent paroxysms of one or several types of a wide spectrum of supraventricular dysrhythmias, which often gave rise to troublesome symptoms in the form of palpitation, fatigue, and/or congestion, but also made it easier to recognize the cardiac origin of the unspecific cerebral symptoms. Cerebral symptoms occurred suddenly and unexpectedly, and often disabled the patients to a severe degree. Drug treatment proved of little value, but pacemaker treatment stopped the cerebral attacks in all the 39 cases in which it was performed. In 3 out of 24 patients pacemaker implantation also abolished the tendency for paroxysms of tachydysrhythmias; in the remaining 2I it allowedfor maximal drug treatment which led to nearly total relieffrom tachydysrhythmias in 17.