Impacts Of Atrial Pacing Percentage Of Double Chamber Pacemaker On Incidence Of Atrial Fibrillation In Patients With Sick Sinus Syndrome

Objective To explore the effect of the incidence of atrial fibrillation (AF) under smallinfluence of the cumulative percentage of ventricular pacing and different cumulativepercentage of atrial pacing of double chamber pacemaker in patients with sick sinus atrialnode syndrome (SSS).Methods A total of60patients were chosen who received DDD (R) pacemaker forSSS and their function of the atrioventricular node were normal, according to the followinginformation such as the medical records of implanted pacemaker in hospital and outpatientfollow-up after operation, regular pacemaker SPC, routine12lead electrocardiogram,dynamic electrocardiogram,conventional two-dimensional echocardiography.they had beeninvestigated after surgery for24months to72months and their accumulated ventricularpacing percentage (Cum%VP)＜20%during the follow-up period. According to theaccumulated atrial pacemaker percentage (Cum%AP)，the subject were divided into threegroups: group A: Cum%AP＜40%(n=19);group B:Cum%AP≥40%～＜80%(n=25);group C: Cum%AP≥80%(n=16).The primary end point was the incidence of atrialfibrillation.The second end points were changes in left atrial(LA) and left ventricularend-diastolic diameters(LVEDD),as well as left ventricular ejection fraction(LVEF)measured by echocardiography.Results The information of three patients in general, such as gender, age, mergecoronary heart disease, diabetes and so on were no statistical difference; Three selectedgroups all have AF. In group A with3cases of AF, B group of nine cases of AF, there are13cases of AF in group C. The incidence of AF of three groups, respectively,15.79%,36.00%,81.25%, The comparison between the three groups were statistically difference (P＜0.05), The results of pair-wise comparison: group A and group C (P＜0.05), the difference was statistically significant; Group A and group B (P=0.253), group B andgroup C (P=0.128), there were no statistically significant differences in. The left atrialdiameter, left ventricular end-diastolic diameter of three groups increased with the increaseof Cum%AP. The difference was statistically significant between the three groups (P＜0.05). The results of pair-wise comparison were statistically difference (P＜0.05), LVEFdecreased with the increase of Cum%AP,but there were no statistical difference betweenthree groups. In the same time,there were no significantly worse in patients with cardiacfunction (NYHA heart function classification Ⅲ, Ⅳ) until the end of follow-up.Conclusion At the point of cumulative percent atrial pacing is small influence on theirheart in SSS patients implanted with DDD,with the increasing of Cum%AP,the increasingincidence of atrial fibrillation. At the same time, the left atrium diameter, left ventricularend-diastolic diameter increased, LVEF has no obvious change.