LONG-TERM RELIABILITY OF SINGLE-LEAD ATRIAL SYNCHRONOUS PACING SYSTEMS USING CLOSELY SPACED ATRIAL DIPOLES - 5-YEAR EXPERIENCE

To assess the long-term capability of single atrioventicular (AV) lead VDD pacing systems using close atrial dipoles to assure reliable atri al guided pacing, the safety and efficacy of 86 VDD units implanted in 73 patients at a single center since November 1988 was reviewed. All patients suffered from advanced AV block with normal sinoatrial functi on. Sixty five patients received a LEM/CCS Twinal 30/30S system, four patients received a Vitatron-Saphir system, and four patients received a Medtronic Thera VDR 8348 system. All patients underwent provocative tests in search of myopotential interference, and Holter recordings; in a group of patients who underwent pacemaker replacement a compariso n was made between implant and replacement measurements. The mean foll ow-up duration was 27.3 months. A high percentage of successfully VDD paced patients and a low incidence of pacemaker malfunction, regularly solved by pacemaker reprogramming, was reported. Atrial signal amplit udes comparable to those measured at implant were found at replacement in all patients. These data support the long-term reliability of sing le AV lead VDD pacing systems with closely spaced atrial dipoles, as w ell as stable atrial sensing by floating bipolar atrial electrodes and effective atrial synchronous ventricular pacing over time.