Cardioprotective effect of unstable angina prior to acute anterior myocardial infarction.

To evaluate the difference in the process of left ventricular functional recovery after successful percutaneous transluminal coronary angioplasty (PTCA), 25 patients with sudden onset of acute Q wave anterior myocardial infarction (MI [group 1]) and 28 patients with unstable angina prior to MI (group 2) were investigated in the late hospital phase. The circumferential extent of left ventricular dysfunction was significantly larger in group 1 than in group 2. The left ventricular ejection fraction (EF) and the ratio of systemic arterial systolic blood pressure to left ventricular end-systolic volume (P/V ratio) were significantly lower in group 1 compared with group 2. The P/V ratio had nonlinear relationships with left ventricular end-diastolic volume (LVEDV) in both groups and the P/V ratio in group 1 was significantly lower than those in group 2 at any given LVEDV. Thus, in patients with successful PTCA, unstable angina prior to acute MI had better left ventricular pump function in the course of left ventricular remodeling.