Right heart in cardiac pacing

Abstract

Conventional right heart pacing with leads placed at the right atrial appendage (RAA) and right ventricular (RV) apex produces iatrogenic dyssynchrony. Atrial dysssynchrony may favor the development of atrial tachyarrhythmias, but the data have been relatively limited and have not yet had any influence on clinical practice. However, the evidence of deleterious effects of the iatrogenic dyssynchrony in the form of left bundle branch block (LBBB) which is produced by RV apical pacing has been compelling and has led to some degree of a paradigm shift in our approach to conventional RV pacing by adopting selective site pacing and avoiding the RV apex, at least for patients with left ventricular (LV) dysfunction and/or heart failure, who are the ones who seem to be afflicted the most and are apparently better responders to non-RV apical pacing. The type of inter- and intra-ventricular dyssynchrony produced by classical RV apical pacing (iatrogenic LBBB) leads to pacing-induced cardiomyopathy similar to the dyssynchrony conferred by spontaneous LBBB, both manageable by biventricular pacing or cardiac resynchronization therapy (CRT). The evidence regarding the adverse effects of conventional right heart pacing is analyzed and reviewed in this chapter together with the data concerning selective or alternate site right heart pacing.