The sick sinus syndrome. Clinical and electrocardiographic spectrum of nine patients.

The paper presents a report on the clinical and electrographic spectrum of nine patients with the sick sinus syndrome with severe symptoms of clinical disturbances and serious disorders of impulse formation and conduction. Seven patients had syncope associated with sinus bradycardia, sinoatrial block or atrial fibrillation with slow ventricular rate. Prolonged episodes of atrial and ventricular asystole occurred and were interrupted by junctional escape beats. Paroxysmal atrial fibrillation and flutter were foun in three patients and infrahisian block in four. Atropine induced a slight acceleration of the heart rate in all the patients studied while the post-suppression S-A node recovery time was prolonged in four.