Abstract 2475: Time Course Of Response To Cardiac Resynchronization Therapy In Patients With Ischemic And Non-ischemic Cardiomyopathy
Background. Cardiac resynchronization therapy (CRT) results in improved left ventricular (LV) systolic function expressed by reduction in LV end-systolic volume (ESV). However, it is still not well known whether this reduction in LVESV occurs immediately after CRT (acute response) or whether some pts need more time to improve in LVESV. Aim of the study was to evaluate the time course of response (improvement in LVESV) to CRT. Particularly, the time course of response was compared between pts with ischemic and non-ischemic cardiomyopathy.
Methods. 95 consecutive heart failure pts (84 men; 65±10yrs, 60 pts with ischemic cardiomyopathy and 35 pts with non-ischemic cardiomyopathy) scheduled for CRT, were included. 2D echocardiography was performed before, immediately after CRT and at 6 months follow-up (6MFU) to evaluate LVESV and LV ejection fraction (EF).
Results. Immediately after CRT, a significant reduction in LVESV was observed combined with a significant increase in LVEF. At 6MFU a further improvement in LVESV and LVEF was noted (Table⇓).When a reduction in LVESV>15% was used to define response to CRT, 38% exhibited an acute response, with an additional 18% at 6MFU resulting in a total of 56% responders to CRT. In pts with ischemic cardiomyopathy (63%), 28% exhibited an acute response, with an additional 17% at 6MFU resulting in 45% responders. In non-ischemic pts, 54% (P<0.05 vs ischemic pts) exhibited acute response, with an additional 20% at 6MFU resulting in 74% responders.
Conclusions. The beneficial effect of CRT on LV systolic function occurs immediately after CRT implantation, with an additional improvement at 6MFU. Pts with ischemic cardiomyopathy need more time to respond to CRT.