Clinical experience with permanent atrioventricular sequential pacing.

In a 23-moth period, we implanted 26 permanent atrioventricular (AV) sequential pacing units in 11 women and 15 men ranging from 37 to 85 years old (mean, 68 years). Indications for pacing were complete heart block n 12 patients and sick sinus syndrome in 14 patients. Cardiac index, using standard thermodilution techniques, was determined in 9 patients during ventricular pacing and AV sequential pacing at constant heart rate. Atrioventricular sequential pacing was superior in all patients, with a mean increase in cardiac index of 22% (p greater than 0.01). Complications of AV sequential pacing included the need to revise two pulse generator pockets due to the large size of the pulse generator. One transvenous atrial lead displacement occurred in a patient who had previously undergone right atrial appendage ligation at open-heart operation. No failures of pacing or sensing occurred during 279 patient-paced months. The theoretical hemodynamic advantage of AV sequential pacing has been confirmed in this clinical trial. Experience with electrode placement and improvements in pulse generator design should aid in eliminating complications with this pacing modality.