A NEW PACING ALGORITHM FOR OVERDRIVE SUPPRESSION OF ATRIAL-FIBRILLATION

Constant rapid pacing may suppress arrhythmias, but it is usually poor ly tolerated in the long term. We report a pilot study of a new pacing algorithm for overdrive suppression of atrial premature Complexes (AP Cs) and atrial fibrillation (AF), which prevents postextrasystolic pau ses and varies the pacing rate in response to the frequency of APCs. T he algorithm was tested in a multiple crossover study for 24 hours in dual chamber pacemakers implanted in 70 patients. Comparison was made on ambulatory recordings between the number of atrial arrhythmias comm encing with the algorithm active and inactive. In all cases, the algor ithm functioned as designed. No patient was aware of its operation, an d no malignant arrhythmias were induced. The 36 recordings that showed atrial arrhythmia were included for analysis. The effects of the algo rithm were: APCs (estimated from pacemaker statistics) reduced in 18 p atients, increased in 8 (P = 0.02); atrial salves reduced in 12, incre ased in 4 (P = 0.041); and AF reduced in 11, increased in 8 (P = NS). In all patients with frequent AF (> 5 episodes in total), fewer episod es occurred when the algorithm wets active. We conclude that the algor ithm is safe and well tolerated, reduces atrial ectopic activity, and may reduce the frequency of sustained atrial fibrillation.