Clinical and Electrophysiological Data in 41 Patients with Sinus Node Dysfunction

DISTURBANCES OF SINUS NODE AUTOMATICITY or of sinoatrial conduction or both have been assumed to occur in the sick sinus syndrome.' 6 A direct estimation of these parameters is not yet possible in man. Indirect methods have therefore been used for evaluation of sinus node function. Estimation of sinus node recovery time after overdrive suppression is a clinically useful method for evaluation of sinus node automaticity.'1 4, 5. 7-11 Sinoatrial conduction time may be evaluated by premature atrial stimulation as proposed by Strauss et al.'2 Studies evaluating both parameters of sinus node function in the same group of patients have been rare.7 131 Therefore we compared sinus node recovery time (SRT) and calculated sinoatrial conduction time (SACT) in 41 patients with sinus node dysfunction to these measures in 20 normal subjects.