Heart rate variability as a means of assessing prognosis after acute myocardial infarction. A 3-year follow-up study

Eur Heart J. 1997 May;18(5):789-97. doi: 10.1093/oxfordjournals.eurheartj.a015344.

Abstract

Aims: The present study evaluated the prognostic value of heart rate variability after acute myocardial infarction in comparison with other known risk factors. The cut-off points that maximized the hazards ratio were also explored.

Patients and methods: Heart rate variability was assessed with 24 h ambulatory electrocardiography in 74 patients with acute myocardial infarction, 4 +/- 2 days after hospital admission and in 24 healthy controls. Patients were followed for 36 +/- 15 months.

Results: During follow-up, 18 patients died, nine suffered a non-fatal infarction and 20 underwent revascularization procedures. Heart rate variability was higher in survivors than in non-survivors (P = 0.005). This difference was found at higher statistical levels when comparing non-survivors vs controls (P = 0.0002). A similar statistically significant difference was also found between survivors vs controls (P = 0.04). Patients suffering non-fatal infarction and cardiac events (defined as death, non-fatal infarction or revascularization) had a lower heart rate variability than those without (P = 0.03 and P = 0.03, respectively). With multivariate regression analysis, decreased heart rate variability independently predicted mortality and death or non-fatal infarction. The presence of a left ventricular ejection fraction < 40% and a history of systemic hypertension were, however, stronger predictors. The cut-off points that maximized the hazards ratio using the Cox model differed from those reported by others.

Conclusion: Decreased heart rate variability independently predicted poor prognosis after myocardial infarction. However, the cut-off points that should be used in clinical practice are still a matter for further investigation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cardiovascular Agents / therapeutic use
  • Electrocardiography, Ambulatory / statistics & numerical data*
  • Female
  • Follow-Up Studies
  • Heart Rate / drug effects
  • Heart Rate / physiology*
  • Humans
  • Male
  • Middle Aged
  • Myocardial Infarction / drug therapy
  • Myocardial Infarction / mortality*
  • Myocardial Infarction / physiopathology
  • Proportional Hazards Models
  • Risk Factors
  • Sensitivity and Specificity
  • Signal Processing, Computer-Assisted
  • Survival Rate

Substances

  • Cardiovascular Agents