TIME-DEPENDENCE OF LEFT-VENTRICULAR RECOVERY AFTER DELAYED RECANALIZATION OF AN OCCLUDED INFARCT-RELATED CORONARY-ARTERY - FINDINGS OF A PILOT-STUDY

Objectives. We sought to test the hypothesis that late recanalization of infarct related coronary arteries (IRAs) improves long term left ve ntricular (LV) function. Background. Reperfusion,within 24 h of an acu te myocardial infarction (MI) has been shown to improve myocardial hea ling and to reduce infarct expansion. Uncontrolled data suggest that t here may be a time,window of several weeks for such an effect. Methods . Sixteen asymptomatic patients 10 +/- 4 days after a first Q wave ant erior wall MI with persistent left anterior descending coronary artery occlusion and infarct-zone akinesia were randomized to immediate (2 w eeks) or delayed (3 months) angioplasty. Repeat catheterization and ca rdiac magnetic resonance imaging (MRI) were performed after 3 and 12 m onths. Results. Angiography 3 months after MI revealed that LV ejectio n fraction (LVEF) had increased ([mean +/- SD] 54.4 +/- 4.3% vs. 63.9 +/- 7.4%, p < 0.01) as a result of improved regional function (p < 0.0 1) and LV end-systolic volume had decreased (p < 0.002), whereas LV en d-diastolic volume remained un changed. With delayed angioplasty, LVEF , infarct zone wall motion and LV volumes did not improve. Cardiac MRI at baseline and at 3 and 12 months confirmed these findings and exten ded them up to 1 year, indicating that delayed angioplasty could no lo nger improve LV function because of marked LV dilation (p < 0.01). Imm ediate angioplasty had a high success rate, but restenosis (50%) was a ccompanied by new severe angina as a clinical indicator of salvaged my ocardium, which did not occur after delayed angioplasty. Conclusions. This pilot study in selected patients supports the hypothesis that myo cardial viability persists (''hibernation'') for 2 to 3 weeks but not for 3 months after MI, during which time it may be worthwhile to resto re blood flow to a large myocardial territory, even in asymptomatic pa tients, to improve long-term LV function. (C) 1998 by the American Col lege of Cardiology.