Alternate Site Pacing in Patients at Risk for Heart Failure

Abstract

Cardiac pacing from the right ventricular apex is the most common site of cardiac pacing. During the last decade, several studies demonstrated the harmful effects of the iatrogenic left bundle branch block, which is observed in cardiac pacing from the right ven- tricular apex. These observations led to an interest in alternative right ventricular pacing sites aiming to achieve a more “physiological” pattern of ventricular activation. Alternate site pacing may involve His bun- dle, other right ventricular sites (outflow or septal sites), or left ventricular sites in either unifocal or bifo- cal or biventricular modes. Pacing from the right ven- tricular outflow tract has been studied extensively. Several studies showed that right ventricular outflow tract pacing has better hemodynamic effects and less harmful influence. Bifocal right ventricular (apical and outflow tract) pacing has been proposed for patients with heart failure where the coronary sinus approach to effect biventricular pacing turns out to be unsuccessful because of various reasons. Some studies examined left ventricular pacing alone as an alternative mode of pacing, and the results were quite encouraging but not conclusive. Finally, in heart failure patients not responding to biventricular pacing, the triple site pacing mode has been recently proposed. In triple site pacing, the leads are inserted in the right ventricular apex and outflow tract in conjunction with lateral left ventricular pacing. Improvement of exercise capacity and increased ejection fraction were observed with this triventricular pacing. Although more data from specifically designed randomized studies are needed, there are many alternative pacing sites, especially for patients at high risk of heart failure, which seems to be less harmful and better tolerated by the patients.

Optimization of Left Ventricle Pace Maker Location Using Echo-Based Fluid-Structure Interaction Models

“…Furthermore, clinical trials have shown that RVA pacing can cause electro-mechanical contraction of the left and right ventricles to be asynchronous. Long-term RVA pacing can cause cardiac histologic and electrical remodeling, abnormal myocardial contractile pattern, hemodynamic disorder, and ultimately cardiac insufficiency, there is also the risk of atrial fibrillation (AF) and heart failure (HF), which increases the rate of hospitalization and mortality ( Manolis et al, 2008 ; Miranda et al, 2012 ; Alhous et al, 2015 ). So optimization of right ventricular pacing site becomes an important object of pacing electrophysiology.…”