The American journal of cardiology
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Randomized Controlled Trial Clinical Trial
Metoprolol in acute myocardial infarction. Patients and methods. The MIAMI Trial Research Group.
The effects of early intervention with metoprolol in patients with suspected or definite acute myocardial infarction (AMI) have been assessed in a randomized, double-blind, placebo-controlled international study. Patients aged 75 years or younger were eligible for entry if they presented to a coronary care unit within 24 hours of the onset of symptoms of an AMI. Exclusion criteria included current treatment with a beta blocker or calcium-channel blocker, heart rate less than or equal to 65 beats/min, systolic blood pressure less than or equal to 105 mm Hg, contraindications and other administrative reasons. ⋯ The study period was 15 days in addition to the day of randomization. The patients' clinical history and status at entry were documented. The following outcome variables were recorded: mortality, development of AMI, serum enzyme activity, electrocardiographic signs of AMI, late or recurrent AMI, arrhythmias, treatment of chest pain, concomitant treatment, adverse events and details of treatment with trial medication.
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Randomized Controlled Trial Clinical Trial
Metoprolol in acute myocardial infarction. Mortality. The MIAMI Trial Research Group.
After 15 days there were 142 deaths in the placebo group (4.9%) and 123 deaths in the metoprolol group (4.3%), a difference of 13% (p = 0.29). The 95% confidence limits for the relative effect of metoprolol ranged from an 8% excess (-8%) to a 33% reduction (+33%) in mortality. There was generally a lower mortality rate for metoprolol-treated patients in most subgroups and a consistent tendency for a more pronounced difference between the treatment groups in those subgroups with a placebo mortality rate higher than the average for all placebo patients. ⋯ Using a simple model, the placebo mortality was found to increase with increasing number of 8 risk predictors defined from prestudy experience, from 0% in patients with no risk predictors to 11.6% in patients with any 5 or more of these risk factors. Similarly, there was an increase in the difference between the treatment groups in favor of metoprolol with increasing number of placebo risk factors. Metoprolol had no apparent effect in a low-mortality risk group (less than or equal to 2 risk factors), but there was a difference in mortality of 29% in favor of metoprolol in a high-risk group (greater than or equal to 3 risk factors) comprising one-third of the trial population.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Metoprolol in acute myocardial infarction. Enzymatic estimation of infarct size. The MIAMI Trial Research Group.
The maximum serum activity for aspartate aminotransferase (s-ASAT) during the first 3 days was recorded in 5,507 patients with suspected or definite acute myocardial infarction. The s-ASAT activity was corrected for the normal range from each center. ⋯ Univariate analyses indicated that the delay time between onset of symptoms and randomization and sympathetic activity at entry significantly influenced the effect of metoprolol. A similar decrease in serum enzyme activity after metoprolol treatment was observed independent of signs of infarct localization on the entry electrocardiogram.
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Randomized Controlled Trial Clinical Trial
Metoprolol in acute myocardial infarction. Other clinical findings and tolerability. The MIAMI Trial Research Group.
Fifteen minutes after injection there was a fall in mean heart rate (18%, p less than 0.001), systolic blood pressure (10%, p less than 0.001) and rate-pressure product (27%, p less than 0.0001) in the metoprolol group of patients in the MIAMI trial. Hypotension and bradycardia not necessarily associated with withdrawal of drug were more common in the metoprolol group (p less than 0.001). Atrioventricular block I was more common in the metoprolol group (p less than 0.03), whereas no such difference was observed for atrioventricular block II and III, asystole or pacemaker implantations. ⋯ The trial medication was withdrawn temporarily more often in the metoprolol than in the placebo group (p less than 0.001). However, permanent withdrawal of trial medication occurred with a similar frequency overall in both groups. More patients were withdrawn from the study because of cardiovascular reasons in the metoprolol group (9%) than in the placebo group (5%, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Metoprolol in acute myocardial infarction. Development of myocardial infarction. The MIAMI Trial Research Group.
The effect of metoprolol on the development of an acute myocardial infarction (AMI) during days 0 to 3 and on late first and recurrent infarctions during days 4 to 15 has been investigated. Signs on electrocardiogram (ECG) were well balanced between the treatment groups at entry; 70% of patients had signs of suspected AMI and 19% of patients had normal ECGs. The remaining patients had abnormal ECGs but actual infarction could not be localized. ⋯ No difference in the effect of metoprolol regarding localization of the early AMI was observed. Late first myocardial infarction development (days 4 to 15) was observed in 20 patients (0.7%) in each group. Recurrent myocardial infarction tended to develop more frequently during days 4 to 15 in the placebo group compared with the metoprolol group (3.9% vs 3.0%, p = 0.08).(ABSTRACT TRUNCATED AT 250 WORDS)