ATRIAL SEPTAL PACING - A METHOD FOR PACING BOTH ATRIA SIMULTANEOUSLY

By pacing both atria simultaneously, one could reliably predict and op timize left-sided AV timing without concern for IACT. With synchronous depolarization of the atria, reentrant arrhythmias might be suppresse d. We studied four male patients (73 +/- 3 years) with paroxysmal atri al fibrillation and symptomatic bradyarrhythmias using TEE and fluoros copy as guides; a standard active fixation screw-in lead (Medtronic mo del #4058) was attached to the interatrial septum and a standard tined lead was paced in the ventricle. The generators were Medtronic model 7960. The baseline ECG was compared to the paced ECG and the conductio n time were measured to the high right atrium, distal coronary sinus a nd atrial septum in normal sinus rhythm, atrial septal pacing, and AAT pacing. On the surface EGG, no acceleration or delay in AV conduction was noted during AAI pacing from the interatrial septum as compared w ith normal sinus rhythm. The mean interatrial conduction time for all 4 patients was 106 +/- 2 ms; the interatrial conduction time measured during AAT pacing utilizing the atrial septal pacing lead was 97 +/- 4 ms (P = NS). During atrial septal pacing, the mean conduction time to the high right atrium was 53 +/- 2 ms. The mean conduction time to th e lateral left atrium during atrial septal pacing, was likewise 53 +/- 2 ms. We conclude that it is possible to pace both atria simultaneous ly from a single site using a standard active fixation lead guided by TEE and fluoroscopy. Such a pacing system allows accurate timing of th e left-sided AV delay.