Angiotensin-Converting Enzyme Inhibitor Therapy Affects Left Ventricular Mass in Patients With Ejection Fraction >40% After Acute Myocardial Infarction

Objectives. We tested the hypothesis that angiotensin-converting enzyme (ACE) inhibitor therapy decreases left ventricular (LV) mass in patients with left ventricular ejection fraction (LVEF) >40% and no evidence of heart failure after their first acute Q wave myocardial infarction (MI). Background. Recently, ACE inhibitor therapy has been shown to have an early mortality benefit in unselected patients with acute MI, including patients without heart failure and LVEF >35%. However, the effects on LV mass and volume in this patient population have not been studied. Methods. Thirty-five patients with LVEF >40% after their first acute Q wave MI were randomized to titrated oral ramipril (n = 20) or conventional therapy (control, n = 15). Magnetic resonance imaging (MRI) performed an average of 7 days and 3 months after MI provided LV volumes and mass from summated serial short-axis slices. Results. Left ventricular end-diastolic volume index did not change in ramipril-treated patients (62 ± 16 [SD] to 66 ± 17 ml/m2) or in control patients (62 ± 16 to 68 ± 17 ml/m2), and stroke volume index increased significantly in both groups. However, LV mass index decreased in ramipril-treated patients (82 ± 18 to 73 ± 19 g/m2, p = 0.0002) but not in the control patients (77 ± 15 to 79 ± 23 g/m2). Systolic arterial pressure did not change in either group at 3-month follow-up. Conclusions. In patients with LVEF >40% after acute MI, ramipril decreased LV mass, and blood pressure and LV function were unchanged after 3 months of therapy. Whether the decrease in mass represents sustained effect that is associated with decrease in morbid events requires further investigation.