Lessons Learned and Insights Gained in the Design, Analysis, and Outcomes of the COMPANION Trial

Correction of LV Mechanical Dyssynchrony by Biventricular Pacing

(Left) Left bundle branch block producing an intraventricular conduction delay, leading to delayed depolarization of the left ventricular (LV) mid free wall and dyssynchronous LV contraction. (Right) Restoration of synchronous LV contraction by bypassing the conduction block with direct simultaneous pacing of the LV free wall and right ventricular septum. In both panels, the blue line is the His-Purkinje system and the dashed line is cardiac myocyte depolarization. AV = atrioventricular.