A Retrospective Study: The Impact Of Chronic Right Ventricular Apical Pacing On Cardiac Function In Patients With Third Degree A-V Block

BACKGROUND:Rght ventricular apex(RVA) has been selected as the traditional site for lead positioning of pacing.Howerver,emerging data have suggested that chronic RVA pacing could lead to left ventricular(LV) dysfunction and new-onset of heart failure(HF),which due to the abnormal sequence of cardiac activation and adverse hemodynamic changes during RVA pacing.OBJECTIVE:The aim of our study was to evaluate the incidence and risk factors of new-onset heart failure and left ventricular impairment in patients who underwent permenent RVA pacing and had normal baseline cardiac function.METHODS and RESULTS:We included 92 patients with three degree A-V block and preserved LV function in this study.We excluded patients who had structural heart diseases which could obviously effect their cardiac function.All 92 patients received RVA pacing and after 10.6±5.8 years of follow up,8 of them(8.7%) developed new-onset heart failure(after 12.4±6.0 years of pacing),and 22 of them (23.9%) developed LV impairement as we observed by echo(after 12.6±7.5 years of pacing).Single factor analysis of the patients' gender,age at implantation,years of pacing,pacing mode(VVI or DDD),presence of hypertention,presence of diabetes (DM),presence of ischemic heart disease and presence of atrail fibrillation(Af) showed that none of these factors are related with the incidence of new-onset heart failure or LV impairment.CONCLUSIONS:Among patients with normal baseline LV function who underwent permenent RVA pacing,a certain percentage of them did develop new-onset heart failure or LV impairment throughout the years.However,in this study,risk factors for heart failure or LV impairment in such patients remained unknown.