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End-systolic volume index is the major predictor of survival after coronary artery bypass graft surgery in patients with impaired left ventricular function. Strategies to prevent ventricular dilatation, such as angiotensin-converting enzyme inhibitors, may improve the long-term outcome in these patients.

SUMMARY The effect of propranolol (0.1 mg/kg intravenously followed by 320 mg given over 27 hour orally) on serum levels of creatine kinase enzyme was studied in a randomized trial involving 95 patients seen within 12 hours of onset of symptoms of uncomplicated myocardial infarction. In 15 patients who were treated with propranolol within 4 hours of onset, and who eventually developed pathological Q waves, peak measured enzyme levels were 27% (P < 0.0125) lower than in 19 control patients who were also seen THE WELL-KNOWN EFFICACY of beta-adrenergic blocking drugs for the treatment of angina pectoris53 suggests that these drugs should also be effective for the acute imbalance between oxygen supply and demand which occurs during the early stages of myocardial infarction. Apart from an encouraging report by Snow in 1965,4 however, a number of carefully randomized early clinical trials of beta blockers5-9 showed no effect on hospital mortality from infarction nor on the incidence of arrhythmias in treated patients compared with controls.A number of recent developments suggest, however, that the use of beta-adrenergic blocking drugs in the acute stage of myocardial infarction should be re-investigated. First, there is the evidence that long-term beta blockade prolongs life after myocardial infarction'0 11 and that this may be due in part to the prevention of new ischemic events.'2 Second, there is evidence that propranolol given prophylactically to experimental animals reduces myocardial infarct size;3-5 this suggests that measurements of infarct size should be used as an end-point for therapeutic trials in man. Third, doses of propranolol used in previous trials (40-80 mg per day) were comparatively low and were administered orally and comparatively late after the onset. Patients given this low dose do not develop blood levels within the therapeutic range for 24-48 hours after first administration of the drug. 16The present trial proposed to investigate the effect of highloading doses of propranolol given within 12 hours of onset of symptoms of infarction on serum creatine phosphokinase (CPK) levels.'7', Results show that CPK levels were reduced by propranolol if the drug was given within four hours of onset of the most severe chest pain.Patients and MethodsWe included in this study those infarctions which were of moderate severity since we postulated they would ultimately within 4 hours of the onset but had no specific treatment. Total calculated enzyme appearance was also lower in the treated patients (reduced 25%, P < 0.05) as was the calculated rate of appearance (33%, P < 0.005). No significant difference was found for treated compared with control patients entering the trial more than 4 hours after the onset of chest pain. This evidence suggests that propranolol may reduce the size of uncomplicated infarctiops if it is given intravenously within 4 hours of the onset.cause a moderately high enzyme release for which a reduction would be both easily measurable and clinically meaningful. At the same time it was r...

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