Long-term Follow-up of the Patients with Permanent Antibradycardia Pacemaker

ABSTRACT

BACKGROUND: Antibradycardia pacemaker is one of the treatment modalities for bradyarrhythmia. We present the clinical results of 440 implantations of permanent pacemaker between August 1984 and December 1997 at Department of Internal Medicine in Seoul National University Hospital. METHOD: We investigated the indication of permanent pacing, the pacing modes, the complications of permanent pacing, and the chronic pacing threshold. RESULT: The study was comprised of 440 patients (M/F 179/261, mean age 59+/-12 years, 58+/-14 years, respectively). Indications of the primary pacemaker implantations were sinus node dysfun-ction in 53% and atrioventricular conduction disorders in 47%. Twelve percent of total pacemaker procedures were pulse-generator replacements. Pacing modes were VVI in 59.1%, VVIR in 10.2%, DDD in 30.2%, and others in 0.5%. Complications developed in 21 cases (4.8%) during long-term follow-up. They included 8 cases of pacing failure due to increased pacing threshold, 2 cases of early power depletion, 2 cases of lead dislodgement, 6 cases of lead fracture, 3 cases of skin erosion, 3 cases of hematoma, 3 cases of infection, and 1 case of skeletal muscle stimulation. Chronic pacing thresholds at pacing width of 0.5 msec were 1.9+/-0.4 V for the epicardial ventricular leads (n=11), 1.3+/-0.5 V for the endocardial ventricular leads (n=36), and 1.1+/-0.2 V for the atrial leads (n=4) after 7 to 10 years of implantation. CONCLUSION: Sinus node dysfunction was the more common indication than atrioventricular block for the antibradycardia pacemaker implantation. Long-term follow-up of the pacemaker patients would be very useful to detect the pacing system abnormalities and to maximize the battery longevity by adjustment of pacing output according to the level of chronic pacing threshold.