不同剂量美托洛尔对老年心肌梗死患者心功能的影响

Effect of metoprolol on left ventricular function in elderly patients with acute myocardial infarction

目的通过静息门控断层心肌灌注显像(GSPECT)观察不同剂量美托洛尔对老年急性心肌梗死(AMI)患者左室收缩功能的影响。方法临床确诊的急性心肌梗死老年患者48例,平均年龄(65.7±5.3)岁。按剂量不同分为A组(美托洛尔≤50 mg)和B组(美托洛尔>50 mg,最大剂量为200 mg)。记录用药前及用药后3个月和6个月患者服药的依从性、心衰加重率、心肌梗死再发生率和心律失常发生率,采用99Tcm-MIBI静息心肌门控断层显像观察指标LVEDV、LVESV、LVEF。结果①两组患者均无出现严重心律失常而停药,与B组比较,A组因心衰加重而住院和心肌再梗死发生率均下降。②服药3月,A组心率、心率×收缩压双乘积均下降(均P<0.05),LVEDV值、LVESV值均下降(均P>0.05),LVEF值上升(P>0.05);B组变化同上。③服药6月,两组心率、心率×收缩压双乘积、LVEDV、LVESV分别进一步减小,两组LVEF进一步增高。结论①老年急性心肌梗死患者使用美托洛尔可改善心功能,减少心脏事件发生,在降低心率、血压方面安全有效。②老年急性心肌梗死患者使用较小剂量美托洛尔即可起到改善心功能作用,且只要无使用美托洛尔禁忌证,应长期坚持口服。③老年心肌梗死患者使用美托洛尔是否达到靶剂量更有利于改善患者的远期预后,仍有待于进一步探讨。

Objective To investigate the effect of metoprolol on left ventricular function in the elderly patients with acute myocardial infarction by myocardial perfusion imaging and explore the relationship between dose of β-blocker therapy prescribed and cardiac systolic function improvement. Methods Forty-eight patients with acute myocardial infarction were divided into group A（ n = 22） and group B（ n = 26） based on dose of metopmlol. The cardiac systolic function was measured by gated myocardial perfusion SPECT imaging, meanwhile heart rate, blood pressure and clinical symptoms were also recorded before use of the drugs and on 3 and 6 months after use of the drugs. Results During the following up period, the changes of left ventricular（LV） systolic function improved in groups A and B. After 6-month treatment, LVEF increased： （44.8 ± 16.0） % vs （53.0 ± 16.1） %, （43.8 ± 7.1） % vs （54.0 ± 7.6） %, respectively（P〈 0.05）, The other parameters decreased： LVEDV（94.2 ± 29.7）/min vs （87.5 ± 28.5） /min, （104.7±21.3） ml vs （89.8±17.9）ml, respectively （P〈0.05）;HR（69.1 ±3.6）/min vs（64.9±2.7）/min,（75.4±7.9）/min vs （63.4±2.5）/min, respectively （P〈0.05）.HR×SBP （8 818.4±910.7） times/min·mmHg vs （7 852.7±696.2） times/min·mmHg, （9 717.4 ± 1 262.2） times/min·mmHg vs （ 7 243.5 ± 494.4） times/min·mmHg, respectively （ P 〈 0.05 ）. There was nostatistical significance in both groups A and B in the improvement of left ventricular systolic function. Conclusions （1）Treatmentwith β-adrenergic blockade lowers cardiac events among the elderly after AMI. It is safe that elderly patients with AMI take metopro-lol to lower heart rate and blood pressure. （2）Long-term treatment with metoprolol may improve left ventricular function among elder-ly patients after acute myocardial infarction. The reeovery of left ventricular systolic function is obviously up after 6 months＇ treat-ment. （3）The result does not provide definitive evidence on the best dose.