Early preventive treatment of left ventricular dysfunction following myocardial infarction: optimal timing and patient selection.

Treatment for clinical congestive heart failure is effective, but because severe ventricular dysfunction is often present at the time of clinical presentation, it may only be palliative. Recent clinical studies indicate that treatment of symptomless left ventricular dysfunction from 1 week following myocardial infarction or later may prevent further ventricular dilation and possibly reduce the occurrence of heart failure. Considering the potential for progressive ventricular dilation that exists from the time of myocardial infarction, early intervention following myocardial infarction may provide greater benefit. In a double-blind study, 100 patients with Q-wave myocardial infarction, but without clinical heart failure, were randomized to treatment with captopril 50 mg twice daily or placebo, 24-48 hours following onset of symptoms. During 3 months of treatment, the placebo group showed significant increases in left ventricular end-diastolic and end-systolic volume indices with ejection fraction unchanged. In contrast, the captopril group showed a slight but insignificant increase in left ventricular end-diastolic volume index and a significant reduction in end-systolic volume index with ejection fraction increased. Thus, early treatment of patients following Q-wave myocardial infarction with converting enzyme inhibition is effective in preventing ventricular dilation and provides an advantage over later treatment. Selection of patients with Q-wave infarction at 24 hours, after thrombolysis, provides therapy for those most likely to benefit, which is well tolerated without risk of hypotension.