CORONARY SINUS PACING PREVENTS INDUCTION OF ATRIAL-FIBRILLATION

Background Atrial fibrillation (AF) is due to reentry, and its inciden ce has been shown to decrease after dual-site atrial or biatrial pacin g. We investigated whether a simpler pacing approach via the distal co ronary sinus (CSd) could eliminate AF inducibility by high right atria l (HRA) extrastimuli (APDs). We based our hypothesis on our previous o bservation that AF inducibility by HRA APDs was associated with conduc tion delays to the posterior triangle of Koch, whereas AF was never in duced with CSd APDs, which were associated with minimal intra-atrial c onduction delays. Methods and Results Programmed electrical stimulatio n was performed from the high right atrium and CSd, and bipolar record ings were obtained from the high right atrium, His bundle, posterior t riangle of Koch, and coronary sinus. In 13 patients (age, 44 +/- 18 ye ars), AF was reproducibly induced with a critically timed HRA APD (220 +/- 22 ms) delivered during HRA pacing. AF was not induced in any of the patients when HRA APDs were delivered during CSd pacing at the sam e critical coupling intervals. Coronary sinus APDs delivered during HR A pacing also were not associated with AF induction. The APD coupling interval measured at the posterior triangle of Koch during CSd pacing was significantly prolonged compared with the one measured during HRA pacing and AF induction (381 +/- 58 versus 263 +/- 37 ms; P < .0001). Conclusions We propose that CSd pacing suppresses the propensity of HR A APDs to induce AF by limiting their prematurity at the posterior tri angle of Koch and not allowing local conduction delay and local reentr y to occur.