The Continued Search for Physiological Pacing: Where Are We Now?

Cardiac pacing is an effective treatment for patients with bradycardia due to sinus node dysfunction or atrioventricular block. Despite decades of technological advances, the optimal ventricular pacing site to mimic normal human ventricular physiology and best hemodynamic response remains elusive. Beginning with atrial synchronous right ventricular (RV) apical pacing, the search has continued through alternate RV pacing sites, minimizing RV pacing, biventricular pacing, left ventricular (LV) pacing, and His-bundle pacing. Understanding the deleterious effects of long-term RV apical pacing in vulnerable populations has created tremendous interest in alternate pacing options. This paper reviews the current status of available pacing options, with particular focus on His-bundle pacing. Permanent His-bundle pacing has emerged as the leading candidate for physiological pacing because it provides nearly normal electrical activation of both ventricles and thereby avoids ventricular dyssynchrony. Synchronized LV pacing, multisite LV pacing, and LV endocardial pacing offer promise as novel pacing options in select patients.