OBJECTIVETo investigate the effect of anti-atrial fibrillation of Philos DDDR pacemaker on atrial tachyarrhythmia.

METHODSThirty-eight patients with sick sinus syndrome and paroxysmal atrial fibrillation (AF) were implanted with Philos DDDR pacemaker. After implantation, auto-Mode-Switch (AMS) function was switched "on" and AF preventive algorithms were "off" in all cases. The number of AMS, atrial premature beats, heart rate and the percentage of atrial and ventricular pacing were recorded by pacemaker diagnostic function for one-month after procedure. AF preventive algorithms function with "middle" (approx 8 bpm) was then switched on and the same parameters as above from the database of pacemaker diagnostic function were collected for additional one month.

RESULTSThe symptoms of dizziness, dyspnoea, and palpitation in the majority of patients were dramatically improved regardless of whether the AF preventive algorithms function was switched "on" or "off" after pacemaker implantation. There were no significant clinical changes in most patients when AF preventive algorithms were "on". However, 5 cases (13.2%) had palpitations and short of breath. These symptoms were relieved by changing the algorithms from "middle to slight (approx 4 bpm)". When AF preventive algorithms were switched on, atrial premature beats were reduced significantly (P < 0.05) with a dramatic increase in atrial pacing percentage and heart rate (P < 0.05). However, there was no significant difference in AMS (P > 0.05) between the two groups of AF preventive algorithms function switching "on" and "of", indicating that atrial tachyarrhythmias were not inhibited by anti-atrial fibrillation pacemaker.

CONCLUSIONThis study suggested that atrial fibrillation and atrial tachycardia were not reduced by implantation of an anti-atrial fibrillation Philos DDDR pacemaker, although atrial premature beats decreased significantly with increasing atrial pacing percentage when AF preventive algorithms were in "middle" and "slight".