Traditional and nonlinear heart rate variability are each independently associated with mortality after myocardial infarction

J Cardiovasc Electrophysiol. 2005 Jan;16(1):13-20. doi: 10.1046/j.1540-8167.2005.04358.x.


Introduction: Decreased heart rate variability (HRV) and abnormal nonlinear HRV shortly after myocardial infarction (MI) are risk factors for mortality. Traditional HRV predicts mortality in patients with a range of times post-MI, but the association of nonlinear HRV and outcome in this population is unknown.

Methods and results: HRV was determined from 740 tapes recorded before antiarrhythmic therapy in Cardiac Arrhythmia Suppression Trial patients with ventricular premature contractions (VPCs) suppressed on the first randomized treatment. Patients were 70 +/- 121 days post-MI. Follow up was 362 +/- 241 days (70 deaths). The association between traditional time and frequency-domain HRV and mortality and nonlinear HRV and mortality were compared for the entire population (ALL), those without coronary artery bypass graft post-MI (no CABG), and those without CABG or diabetes (no CABG, no DIAB) using univariate and multivariate Cox regression analysis. Strength of association was compared by P values and Wald Chi-square values. Nonlinear HRV included short-term fractal scaling exponent, power law slope, and SD12 (Poincare dimension). For ALL and for no CABG, increased daytime SD12 had the strongest association with mortality (P=0.002 ALL and P <0.001 no CABG). For no CABG, no DIAB increased 24-hour SD12 hours had the strongest association (P <0.001) with mortality. Upon multivariate analysis, increased SD12, decreased ln ULF (ultra low frequency), and history of prior MI and history of congestive heart failure each remained in the model.

Conclusion: Nonlinear HRV is associated with mortality post-MI. However, as with traditional HRV, this is diluted by CABG surgery post-MI and by diabetes. Results suggest that decreased long-term HRV and increased randomness of heart rate are each independent risk factors for mortality post-MI.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Algorithms
  • Arrhythmias, Cardiac / diagnosis
  • Arrhythmias, Cardiac / mortality
  • Clinical Trials as Topic
  • Comorbidity
  • Diagnosis, Computer-Assisted / methods*
  • Electrocardiography, Ambulatory / methods*
  • Female
  • Heart Rate*
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Models, Cardiovascular
  • Myocardial Infarction / diagnosis*
  • Myocardial Infarction / mortality*
  • Nonlinear Dynamics
  • Prognosis
  • Reproducibility of Results
  • Risk Assessment / methods*
  • Risk Factors
  • Sensitivity and Specificity
  • Survival Analysis
  • United States / epidemiology