Assessment of Heart Rate Turbulence in the Acute Phase of Myocardial Infarction for Long‐Term Prognosis

This study is designed to assess the value of heart rate turbulence (HRT) in the acute phase of MI for prediction of long-term mortality risk. The study included 128 consecutive acute MI patients with 24-hour Holter recordings to evaluate HRT (turbulence onset and slope), SDNN, mean RR interval, and ventricular premature beat frequency. LVEF was evaluated by two-dimensional echocardiography. Data from 117 patients (mean age 58 +/- 11 years) were available for further analysis. Twelve patients died during follow-up (mean 312 +/- 78 days). Although SDNN < 70 ms was the most powerful predictor of mortality among all presumed risk factors (hazard ratio 20 [95% CI 2.6-158]; P = 0.004) in univariate Cox regression analysis, in multivariate analysis LVEF < or = 0.40 and turbulence slope < or = 2.5 ms/RR interval were the only independent predictors of mortality (hazard ratio 6.9 [95% CI 1.8-26]; P = 0.006, hazard ratio 7.3 [95% CI 1.4-37]; P = 0.016, respectively). Addition of HRT parameters for LVEF increased remarkably the positive predictive value (60%) without any decrease in the negative predictive value (92%). Blunted HRT reaction within the first 24 hours of acute MI is an independent predictor of long-term mortality. Furthermore, its predictive power is comparable and also additive to that of LVEF.