Clinical Observation Of Early Intravenous Injection With Metoprolol In 173 Patients With Myocardial Infarction

Objective: To demonstrate the effect of early intravenous injection(i.v.) andoral with tolerance more permissible dose Metoprolol on 173 patients with acutemyocardial infarction(AMI) in Qingdao area. To investigate the possible mechanismof Metoprolol in reducing the mortality of AMI.Methods: 173 patients after AMI were randomly double-blind divided intothe treatment group and placebo group according to the treatment with Metoprolol.The two groups were all treated with combined therapy of urokinase or rt-PA, LMWA,aspirin and Nitroglycerin. The treatment group was administered with Metoprololbesides the conventional therapy administered in the placebo group. The treatmentgroup received 5mg Metoprolol i.v. as soon as possible after being hospitalized, alltogether three times in every 5 minutes with the total of 15mg. During the period, thechange of blood pressure and heart rate were carefully observed. Then the treatmentgroup began oral application of Metoprolol 50mg q6h for two days and Metoprololsustained-release tablet 200mg qd for one month. The placebo group received thesame type of placebo drugs i.v. and oral therapy. It was a double-blind study. Theeffect of the two groups were analyzed with T-test after one month. The two groupswere compared in respects of the occurrences of the persistent time of ST-segmentelevating, the heart rate and SBP after 24h therapy, cardiogenic sudden death, heartfailure and cardiogenic shock, relapse of myocardial infarction, stroke afterthrombolysis and death rate.Results: Compared with the Placebo group, the heart rate and SBP after24h therapy and the persistent time of ST-segment elevating were significantlydecreased in the treatment group (P＜0.001), the events of cardiogenic sudden death,relapse of myocardial infarction, stroke after thrombolysis were decreased. Earlytreatment with Metoprolol i.v. can improve the prognosis of patients with AMI. But heart failure worse including cardiogenic shock in the Placebo group were less thanthose in the treatment group (P＜0.05). There were no significant change in the rate ofdeath in two groups(P＞0.05).Conclusion: Early treat with Metoprolol in AMI is useful to reduce the heartrate and SBP after 24h therapy and the persistent time of ST-segment elevating, butincrease with heart failure worse. There were no significant change in the rate of deathin two groups.