Experiences with atrial pacing

The records of 187 patients with permanent atrial pacemakers implanted between 1970 and 1980 were studied retrospectively to define the indications, outcome and short- and long-term complications of single-chamber atrial pacing. Pacemakers were implanted in 145 (77%) patients with tachybrady syndrome, 35 (19%) with sinus bradycardia and 7 (4%) with ventricular arrhythmia. Intact atrioventricular (AV) conduction was defined as absence of second- or third-degree heart block with incremental atrial pacing to a heart rate of 120 beats/min before implantation. The average follow-up was 30 months, including 87 patients (46%) who were followed an average of 48 months. Four patients developed significant conduction disease requiring placement of a ventricular lead. Complications included 4 lead fractures (all coronary sinus leads), 10 dislodgments (9 coronary sinus, 1 tined atrial "J") and 6 threshold rises requiring repositioning of the lead. Eight dislodgments occurred within an average of 5.6 days. The average increase in threshold that required repositioning occurred at 14 days. The average lead fracture occurred at 25 months. Atrial pacing is safe and effective for patients with sinoatrial node disorder (sick sinus syndrome) and intact AV conduction. Progression to clinically significant AV block is uncommon. Complications occur early with coronary sinus leads and are less common with newer leads.