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

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 metoprolol.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(P0.05).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(P0.05);HR(69.1±3.6)/min vs(64.9±2.7)/min,(75.4±7.9)/min vs(63.4±2.5)/min,respectively(P0.05).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(P0.05).There was no statistical significance in both groups A and B in the improvement of left ventricular systolic function.Conclusions ①Treatment with β-adrenergic blockade lowers cardiac events among the elderly after AMI.It is safe that elderly patients with AMI take metoprolol to lower heart rate and blood pressure.②Long-term treatment with metoprolol may improve left ventricular function among elderly patients after acute myocardial infarction.The recovery of left ventricular systolic function is obviously up after 6 months' treatment.③The result does not provide definitive evidence on the best dose.