Short-Term Hemodynamic and Electrophysiological Effects of Cardiac Resynchronization by Left Ventricular Septal Pacing.

Background: Cardiac resynchronization therapy (CRT) is usually performed by biventricular (BiV) pacing. Previously, feasibility of transvenous implantation of a lead at the left ventricular (LV) endocardial side of the interventricular septum, referred to as LV septal (LVs) pacing, was demonstrated.

Objectives: The authors sought to compare the acute electrophysiological and hemodynamic effects of LVs with BiV and His bundle (HB) pacing in CRT patients.

Vectorcardiography for optimization of stimulation intervals in cardiac resynchronization therapy.

Current optimization of atrioventricular (AV) and interventricular (VV) intervals in cardiac resynchronization therapy (CRT) is time consuming and subject to noise. We aimed to prove the principle that the best hemodynamic effect of CRT is achieved by cancelation of opposing electrical forces, detectable from the QRS morphology in the 3D vectorcardiogram (VCG). Different degrees of left (LV) and right ventricular (RV) pre-excitation were induced, using variation in AV intervals during LV pacing in 20 patients with left bundle branch block (LBBB) and variation in VV intervals during biventricular pacing in 18 patients with complete AV block or atrial fibrillation.