老年陈旧性心肌梗死患者心性猝死危险性预测指标的探讨

Methodological study for risk stratification of sudden cardiac death in the elderly patients with previous myocardial infarction

目的探讨４项非创伤性检查指标对老年人陈旧性心肌梗死后心性猝死危险性的预测价值。方法老年人陈旧性心肌梗死７９例，分为猝死组（２２例）和非猝死组（５７例），对比分析两组间４项指标的差异。结果（１）猝死组的左室射血分数（ＬＶＥＦ）和心率变异性指数（ＨＲＶＩ）明显低于非猝死组（Ｐ＜０．０１），而ＱＴ离散度和２４小时动态心电图室性期前收缩（ＶＰＢｓ）＞３０个／小时的发生率在两组间差异无显著性。（２）Ｌｏｇｉｓｔｉｃ多因素回归分析显示ＬＶＥＦ是预测心性猝死危险性的独立指标。如以ＬＶＥＦ４５％为界分组，ＬＶＥＦ＜４５％组的ＶＰＢｓ＞３０个／小时的发生率明显高于ＬＶＥＦ＞４５％组（Ｐ＜０．０１），ＨＲＶＩ明显低于ＬＶＥＦ＞４５％组（Ｐ＜０．０５）。结论老年人心肌梗死伴左心功能不全者易发生心脏自主神经功能失调，诱发严重室性心律失常，导致心性猝死。

Objective To assess the predictive values of 4 noninvasive tests for risk stratification of sudden cardiac death (SCD) after myocardial infarction (MI). Methods The 79 elderly patients with previous were divided into two groups. The SCD group was composed of 22 MI patients who died suddenly within one hour after onset of symptoms. The nonSCD group comprised of 57 MI patients survived. The results of the following 4 noninvasive test in the 2 groups were compared. Results (1)LVEF and HRVI were significantly lower in the SCD group than those in the nonSCD group (P<001), whereas QT dispersion and incidence of VPBs>30/h were not significantly different between the two groups. (2) LVEF was ranked as the best independent predictor for the risk of sudden cardiac death after MI on multifactorial logistic regression analysis. (3)Using LVEF 45% as a cutting point, the incidence of VPBs>30/h was obviously higher (P<001) and HRVI was lower (P<005) in the subgroup with LVEF<45% compared with the subgroup with LVEF>45%. Conclusions The elderly patients with left ventricular dysfunction after myocardial infarction are susceptible to more serious dysfunction of cardiac autonomic nervous system and malignant ventricular arrythmias, causing sudden cardiac death. LVEF is an important index for risk stratification of sudden cardiac death in such elderly patients.