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Impact of reduced heart rate variability on risk for cardiac events. The Framingham Heart Study
H Tsuji1, M G Larson, F J Venditti
1Kansai Medical University, Osaka, Japan.
Insights
Reduced heart rate variability (HRV) predicts future cardiac events in the general population. Ambulatory monitoring of HRV provides prognostic information beyond traditional risk factors for cardiovascular disease.
Area of Science:
- Cardiology
- Preventive Medicine
- Biomedical Engineering
Background:
- Heart rate variability (HRV) changes are observed in various diseases.
- The link between reduced HRV and new cardiac events in large populations remains understudied.
Purpose of the Study:
- To investigate the association between HRV and the risk of new cardiac events.
- To determine if HRV offers prognostic value beyond established cardiovascular risk factors.
Main Methods:
- Ambulatory ECG recordings from 2501 subjects (Framingham Heart Study) were analyzed for HRV.
- Five frequency-domain and three time-domain HRV measures were calculated.
- Proportional hazards regression assessed the association between HRV and cardiac events over 3.5 years.
Main Results:
- Reduced HRV measures were significantly associated with an increased risk of cardiac events.
- A one-standard deviation decrease in total normal RR intervals increased cardiac event risk by 47%.
- These associations remained significant after adjusting for traditional cardiovascular risk factors.
Conclusions:
- HRV assessment via ambulatory monitoring provides valuable prognostic information.
- HRV analysis offers insights into cardiac event risk beyond conventional risk factor evaluation.
Background:
Although heart rate variability (HRV) is altered in a variety of pathological conditions, the association of reduced HRV with risk for new cardiac events has not been studied in a large community-based population.
Methods And Results:
The first 2 hours of ambulatory ECG recordings obtained on subjects of the Framingham Heart Study who were free of clinically apparent coronary heart disease or congestive heart failure were reprocessed to assess HRV. Five frequency-domain measures and three time-domain measures were obtained. The associations between HRV measures and the incidence of new cardiac events (angina pectroris, myocardial infarction, coronary heart disease death, or congestive heart failure) were assessed with proportional hazards regression analyses. There were 2501 eligible subjects with a mean age of 53 years. During a mean follow-up of 3.5 years, cardiac events occurred in 58 subjects. After adjustment for age, sex, cigarette smoking, diabetes, left ventricular hypertrophy, and other relevant risk factors, all HRV measures except the ratio of low-frequency to high-frequency power were significantly associated with risk for a cardiac event (P = .0016 to .0496). A one-standard deviation decrement in the standard deviation of total normal RR intervals (natural log transformed) was associated with a hazard ratio of 1.47 for new cardiac events (95% confidence interval of 1.16 to 1.86).
Conclusions:
The estimation of HRV by ambulatory monitoring offers prognostic information beyond that provided by the evaluation of traditional cardiovascular disease risk factors.