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Correlation of heart rate variability with clinical and angiographic variables and late mortality after coronary
M W Rich1, J S Saini, R E Kleiger
1Division of Cardiology, Jewish Hospital Washington University School of Medicine, St. Louis, Missouri 63110.
Insights
Decreased heart rate variability predicts mortality in patients undergoing coronary angiography. Lower heart rate variability independently indicates higher risk of death within a year, even without recent heart attack.
Area of Science:
- Cardiology
- Clinical Medicine
- Predictive Analytics
Background:
- Heart rate (HR) variability is linked to mortality post-myocardial infarction.
- Prognostic value of HR variability in non-myocardial infarction patients is under-explored.
- Correlation with clinical and angiographic data needs investigation.
Purpose of the Study:
- To assess the prognostic value of HR variability in patients undergoing elective coronary angiography.
- To examine the correlation of HR variability with clinical and angiographic factors.
- To determine HR variability's predictive power for mortality.
Main Methods:
- Prospective study of 100 patients undergoing elective coronary angiography.
- Detailed clinical assessments and 24-hour ambulatory electrocardiograms.
- 1-year follow-up for major clinical events.
Main Results:
- HR variability inversely correlated with HR, diabetes, and digoxin use.
- Left ventricular ejection fraction was the sole predictor of clinical events.
- Decreased HR variability and ejection fraction independently predicted mortality.
- HR variability < 50 ms showed an 18-fold increase in mortality risk.
Conclusions:
- Decreased HR variability is a potent independent predictor of 1-year mortality after elective coronary angiography.
- This finding holds true for patients without recent myocardial infarction.
- HR variability offers significant prognostic information beyond ejection fraction and disease extent.
Abstract:
Decreased heart rate (HR) variability is associated with increased mortality after myocardial infarction, but the prognostic value of HR variability in patients without recent myocardial infarction and its correlation with other clinical and angiographic data have not previously been reported. In the present study, detailed clinical assessments and 24-hour ambulatory electrocardiograms were performed prospectively on 100 patients undergoing elective coronary angiography. HR variability was inversely correlated with HR (r = -0.38, p = 0.001), diabetes mellitus (r = -0.22, p = 0.025) and digoxin use (r = -0.29, p = 0.004), but not with left ventricular ejection fraction, extent of coronary artery disease or other clinical, electrocardiographic or angiographic variables. All patients were followed for 1 year. Major clinical events after initial discharge occurred in 10 patients and included 6 deaths and 4 coronary bypass operations. Left ventricular ejection fraction was the only variable that correlated with the occurrence of a clinical event (p = 0.002). Decreased HR variability and ejection fraction were the best predictors of mortality (both p less than 0.01), and the contribution of HR variability to mortality was independent of ejection fraction, extent of coronary artery disease and other variables. Furthermore, 11 patients with HR variability less than 50 ms had an 18-fold increase in mortality compared with patients with HR variability greater than 50 ms (36 vs 2%, p = 0.001). Thus, decreased HR variability is a potent independent predictor of mortality in the 12 months following elective coronary angiography in patients without recent myocardial infarction.