The role of stress myocardial perfusion to predict left ventricular reverse remodeling in patients with ischemic cardiomyopathy treated by resynchronisation therapy

Purpose: Cardiac resynchronization therapy (CRT) improves quality of life and left ventricular (LV) function in patients (pts) with heart failure; however, improvement in LV function is known to be less evident in ischemic (IC) rather than in non ischemic cardiomyopathy. Assessment of baseline perfusion defects has been used for the prediction of response to CRT in IC; little is known on the effects of myocardial ischemia at the time of implantation on LV reverse remodeling at follow up (FU) in pts treated by CRT. Methods: Fortysix IC pts treated by CRT were studied. All were in NYHA Class III, LVEF ,35%, left bundle branch block with a QRS duration of 154+8 msec, under optimal medical therapy for ischemia and heart failure and no indications to percutaneous or surgical revascularization. Pts underwent conventional echocardiography and stress/ rest myocardial scintigraphy - effort in 28, i.v. dipyridamole in 18 - within 3 weeks before CRT. Among scintigraphic variables, summed rest (SRS), summed stress (SSS) and summed difference score (SDS) were quantitatively analyzed. Results: Pts were divided according to the extension of ischemic area detected by myocardial scintigraphy: Group I (n 32): pts in whom SDS was ≤4, Group II (n 14): pts with SDS .4. No differences were observed between Group I and II in NYHA Class, baseline LVEF, site of previous myocardial infarction, myocardial perfusion score (SRS: 12.4+1.2 vs 10.5+1.6) and pre-CRT echocardiographic end systolic dimensions (ESD): 56.2+1.2 vs 56.3+1.6 mm. At 12+1 month FU, clinical improvement (≥1 NYHA Class reduction) was found in 29/46 pts, 23 in G I pts and 6 in G II pts (p=.05); however, a significant reduction in echocardiographic ESD was seen in G I pts, while no significant changes in ESD could be reported in G II (-9.1+1.2%, vs 20.9+1.1%, p ? 0.01). In the total population, no relation (r ? 0.12) existed between baseline perfusion and changes in ESD at FU. Conclusions: Extension of ischemia evaluated by stress myocardial scintigraphy provides more reliable information than baseline perfusion on LV reverse remodeling in IC pts with no revascularization options treated by CRT