Right Ventricular Septal Pacing: Has it come of age?

Prolonged pacing from the right ventricular (RV) apex has been shown to be associated with progressive left ventricular dysfunction as demonstrated by heart failure, atrial fibrillation and an increased morbidity and mortality [1-6]. This has led to an interest in alternate RV pacing sites and in particular the mid RV septum and the RV outflow tract (RVOT) septum [7-11]. These sites are theoretically associated with a more physiological ventricular activation. Despite the perceived advantages of septal pacing, results to date are not confirmatory [12-18]. These studies were generally acute or extended to 6-months and the leads secured to the RVOT and thus were not necessarily septal. On review of the early work of Durrer et al in 1970 [19] the septal regions of the RVOT and mid RV are the first zones of the ventricle to depolarize, suggesting that pacing from these areas on the right side of the septum would achieve as normal a contraction pattern as possible. In contrast, the free wall of the RV is the last zone to be depolarized. When attempting to prove the physiologic and hemodynamic benefits of septal pacing, it seems illogical to choose the RVOT with a mix of both septal and free wall pacing. The potential benefits of septal pacing would possibly be negated by free wall pacing and thus it is not surprising that there has been no consistent benefit over RV apical pacing demonstrated.