Pacing of the interventricular septum versus the right ventricular apex: a prospective, randomized study.

Background: Left ventricular (LV) function may be impaired by right ventricular (RV) apical pacing. The interventricular septum is an alternative pacing site, but randomized data are limited. Our aim was to compare ejection fraction (EF) resulting from pacing the interventricular septum versus the RV apex.

QRS pattern and improvement in right and left ventricular function after cardiac resynchronization therapy: a radionuclide study.

Background: Predicting response to cardiac resynchronization therapy (CRT) remains a challenge. We evaluated the role of baseline QRS pattern to predict response in terms of improvement in biventricular ejection fraction (EF).

Methods: Consecutive patients (pts) undergoing CRT implantation underwent radionuclide angiography at baseline and at mid-term follow-up.