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Heart rate versus heart rate variability in risk prediction after myocardial infarction
Steen Z Abildstrom1, Berit T Jensen, Erik Agner
1Department of Cardiology, Gentofte University Hospital, Copenhagen, Denmark.
Insights
Heart rate, not heart rate variability (HRV), provides prognostic information after myocardial infarction (MI). This finding was independent of beta-blocker use, suggesting heart rate is a superior predictor of mortality post-MI.
Area of Science:
- Cardiology
- Clinical Research
- Predictive Analytics
Background:
- Acute myocardial infarction (MI) poses significant mortality risks.
- Prognostic markers are crucial for risk stratification post-MI.
- Heart rate (HR) and heart rate variability (HRV) are potential indicators of cardiac health.
Purpose of the Study:
- To compare the prognostic value of HR and HRV in predicting mortality after MI.
- To assess the impact of beta-blocker treatment on the predictive performance of HR and HRV.
Main Methods:
- 366 patients underwent 24-hour Holter monitoring post-MI.
- HRV analyzed as standard deviation of normal-to-normal intervals.
- Left ventricular function assessed via wall motion index.
- Follow-up of 44 months to determine mortality outcomes.
Main Results:
- HRV, HR, wall motion index, ventricular premature beats, and ventricular tachycardia were associated with mortality in univariate analysis.
- In multivariate analysis, only HR, wall motion index, ventricular premature beats, and age independently predicted mortality.
- HRV provided no additional predictive value beyond HR.
Conclusions:
- The prognostic information from HRV is fully encompassed by HR.
- HR offers greater prognostic information than HRV for post-MI risk prediction.
- This relationship is unaffected by beta-blocker therapy.
Introduction:
The aim of this study was to evaluate and compare heart rate and heart rate variability (HRV) in risk prediction after acute myocardial infarction (MI) and to evaluate the effect of beta-blocker treatment on the prognostic performance of heart rate and HRV.
Methods And Results:
Three hundred sixty-six patients underwent 24-hour Holter recording 1 to 6 days after an MI. HRV was expressed as the standard deviation of all normal-to-normal intervals. Left ventricular systolic function was evaluated using the wall motion index. Half of the patients were taking a beta-blocker at the time of Holter recording. Mean follow-up was 44 months (median 34) after MI. By the end of follow-up, 82 patients had died. Mortality at 1 and 3 years was 12.5% and 22.6%, respectively. HRV, heart rate, wall motion index, number of ventricular premature beats per hour, and ventricular tachycardia were all significantly (P < 0.05) associated with mortality in univariate analysis, independent of beta-blocker therapy. In multivariate Cox analysis, only heart rate, wall motion index, number of ventricular premature beats per hour, and age had independent prognostic value (P < 0.001). In any model, including heart rate, HRV had no predictive value.
Conclusion:
The prognostic information of HRV is contained completely in heart rate, which carries prognostic information further than that of HRV. This result was independent of beta-blocker treatment.