POTENTIAL PROISCHEMIC EFFECT OF EARLY ENALAPRIL IN HYPOTENSION-PRONE PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

The objective of this study was to evaluate the relationship between e arly hemodynamic instability and myocardial ischemia and the effect of early intraveneous enalapril therapy on this relationship. In patient s with myocardial infarction (MI), early treatment with angiotensin-co nverting enzyme inhibitors is controversial. In hypotensive patients, initiation of treatment may exacerbate myocardial ischemia and thereby affect the clinical outcome. Therefore, in the CONSENSUS II study, a total of 60 patients randomly allocated to either intravenous enalapri l or placebo treatment commenced within 24 h after the onset of MI wer e evaluated by repeated blood pressure measurements, ambulatory ST-seg ment monitoring before discharge and exercise testing. Significant ST- depression was present in 34 patients. Patients with ST-depression bef ore discharge (residual ischemia) during either exercise testing or am bulatory monitoring or both had a decrease in initial mean arterial bl ood pressure (MAP) of 20 vs. 9 mm Hg in those without ST-depression (n = 24), (p < 0.00001). However, patients (n = 13) with long-lasting ST -depression during Holter monitoring, (>60 min of ST-depression) prese nted with the most severe fall in MAP of 29 mm Hg (p < 0.00001) and a lower systolic blood pressure at inclusion (p < 0.01) compared to the remainder of patients. Furthermore, the number of recurrent acute isch emic events during follow-up was higher in these patients (7 vs. 1; p < 0.01). Ten of the patients treated with enalapril showed a long-last ing ST-depression versus only 3 in the placebo group (p = 0.08), and t he average duration of all significant ST-depressions during Holter mo nitoring was significantly longer in the enalapril group compared to t he placebo group (p < 0.05). Finally, 7 enalapril patients (20%) suffe red an acute ischemic event in contrast to 1 patient (4%) in the place bo group (p = 0.07). In conclusion, early administration of enalapril had a potential proischemic effect in hypotension-prone patients media ted through exacerbation of the hemodynamic response, inasmuch as init ial blood pressure fall after MI is related to residual myocardial isc hemia and recurrent acute ischemic syndromes.