Why and How We Should Avoid Right Ventricular Apical Pacing

A large body of evidence has emerged recently about the harmful effects of chronic right ventricular (RV) apical pacing on left ventricular (LV) function leading to an increase in morbidity and mortality. Right ventricular apical pacing is unphysiologic because it produces aberrant LV depolarization, and in turn mechanical LV dyssynchrony with resultant long-term unfavorable hemodynamic and structural changes. Although the data about RV pacing-induced LV dysfunction outlined in this discussion are persuasive, its clinical applicability in pacemaker practice remains challenging. The ongoing transition to new pacing sites will succeed only with major technologic improvements in lead implantation. Meanwhile, pacing algorithms minimizing right ventricular pacing might be preferable at least in patients with sick sinus syndrome or non-permanent atrioventricular block. I N T R O D U C T I O N A large body of evidence has emerged recently about the harmful effects of chronic right ventricular (RV) pacing (mostly apical) on left ventricular (LV) function. The findings in several important trials correlate with the abnormalities in LV function previously documented in experimental animals subjected to RV pacing. RV pacing is unphysiologic because it produces aberrant LV depolarization, and in turn mechanical LV dyssynchrony with resultant long-term unfavorable hemodynamic (abnormal systolic and diastolic function) and structural changes. Faced with proof that RV apical pacing causes an increase in morbidity and mortality, the question arises as to whether we should continue pacing the apical RV as the preferred site or consider alternative sites to minimize LV dysfunction. Although the data about RV pacing-induced LV dysfunction outlined in this discussion are persuasive its clinical applicability in pacemaker practice remains challenging.