Abstract
We evaluated 113 patients with sick sinus syndrome (SSS) and complete atrioventricular block (AVB) who underwent implantation of DDD pacemaker (PM) between 1982 and May, 1991. Nineteen underwent implantation between 1982 and 1985, when the DDD PM had no function to protect against pacemaker-mediated tachycardia (PMT). During this period, DDD was adopted in only 21% of all implantations. PMT occurred in 37% of patients, and in 21% of patients pacing mode was exchanged. Forty patients underwent implantation between 1986 and May 1989 with the DDD PM with special anti-PMT protection function. DDD PM was selected in 48% of all PM implantations, and PMT occurred in only 5%; 15% of patients required mode exchange. Between June 1989 and May 1991, 54 patients were implanted with the new-generation DDD PM with PMT protection algorithms. DDD PM was selected in 62% of all implantations during this period. Mode exchange was required for only 1 patient (2%), due to transient atrial fibrillation, but, at the time of implantation, DDI mode was initially selected for 6 patients with SSS. PMT occurred in 2 patients (4%) without tachyarrhythmia symptoms.
