Evolving Concepts in Cardiac Physiologic Pacing in the Era of Conduction System Pacing.

Cardiac Physiologic Pacing (CPP) has become a well-established therapy for patients with cardiomyopathy (left ventricular ejection fraction <35%) in the presence of left bundle branch block. Additionally, CPP can be highly beneficial in patients with pacing induced cardiomyopathy and patients with existing cardiomyopathy expected to have a right ventricular pacing burden of > 40%. The benefits of CPP with traditional biventricular (BiV) pacing are only realized if adequate resynchronization can be achieved. However, left ventricular lead implantion can be limited by individual anatomic variation within the coronary venous system and can be adversely affected by underlying abnormal myocardial substrate (i.e. scar tissue), especially if located within the basal lateral wall. In the last seven years the investigation of conduction system pacing (CSP) and its potential salutary benefits are being realized and have led to a rapid evolution in the field of cardiac resynchronization pacing. However supportive evidence for CSP for patients eligible for cardiac resynchronization remains limited in comparison to data available for BiV cardiac resynchronization, mostly deriving from leading CSP investigative centers. In this review we perform an up-to-date comprehensive review of the available literature on CPP.