Time intervals of cardiac resynchronization therapy in heart failure.

Systolic and diastolic time intervals were measured in 11 patients with heart failure before and 1 and 3 months after the placement of atrial biventricular pacemakers for cardiac resynchronization therapy (CRT). CRT shortened the preejection period, principally by reducing left ventricular (LV) electromechanical delay with lesser reduction of isovolumic contraction time, and shortened the duration of LV systole, with a consequent trend of lengthening diastolic time.