The human sinus node electrogram: a transvenous catheter technique and a comparison of directly measured and indirectly estimated sinoatrial conduction time in adults.

To improve methods for evaluating human sinus node function (SNF), we developed a transvenous electrode catheter technique for direct recording of sinus node electrograms in adults. Sinus node electrograms (SNE) characterized by low-frequency, anatomically localized pre-P-wave potentials were obtained in 19 of 23 patients. The SNE configuration was similar to that previously found for endocardial SNE recordings in in vitro atrial preparations, in open-chest dogs and during human open heart surgery. In 16 patients with normal SNF, directly recorded sinoatrial conduction times (SACTs) were 46-116 msec. In three patients with sick sinus syndrome, SACT was 110-126 msec. In 15 of the 19 patients, SACT was estimated by the atrial premature stimulus technique and was compared with the directly measured SACT. When atrial premature depolarizations produced no sinus node depression, the mean differences between the direct and estimated SACT was 1.8 +/- 5.6 msec.