Heart Rate Variability Measured Early in Patients with Evolving Acute Coronary Syndrome and 1-year Outcomes of Rehospitalization and Mortality

Authors

Patricia R.E. Harris, Electrocardiographic Monitoring Research Laboratory, School of Nursing, Department of Physiological Nursing, University of CaliforniaFollow
Phyllis K. Stein, Heart Rate Variability Laboratory, School of Medicine, Division of Cardiology, Washington UniversityFollow
Gordon L. Fung, Cardiology Services, Mount Zion, Department of Medicine, Division of Cardiology, University of California, San FranciscoFollow
Barbara J. Drew, School of Nursing, Department of Physiological Nursing, Division of Cardiology, University of California, San FranciscoFollow

Document Type

Article

Source

Vascular Health and Risk Management

ISSN

1178-2048

Volume

10

First Page

451

Last Page

464

Publication Date

8-2014

Department

Nursing

Abstract

Objective: This study sought to examine the prognostic value of heart rate variability (HRV) measurement initiated immediately after emergency department presentation for patients with acute coronary syndrome (ACS).

Background: Altered HRV has been associated with adverse outcomes in heart disease, but the value of HRV measured during the earliest phases of ACS related to risk of 1-year rehospitalization and death has not been established.

Methods: Twenty-four-hour Holter recordings of 279 patients with ACS were initiated within 45 minutes of emergency department arrival; recordings with �18 hours of sinus rhythm were selected for HRV analysis (number [N] �193). Time domain, frequency domain, and nonlinear HRV were examined. Survival analysis was performed.

Results: During the 1-year follow-up, 94 patients were event-free, 82 were readmitted, and 17 died. HRV was altered in relation to outcomes. Predictors of rehospitalization included increased normalized high frequency power, decreased normalized low frequency power, and decreased low/high frequency ratio. Normalized high frequency �42 ms² predicted rehospitalization while controlling for clinical variables (hazard ratio [HR] �2.3; 95% confidence interval [CI] �1.4–3.8, P�0.001). Variables significantly associated with death included natural logs of total power and ultra low frequency power. A model with ultra low frequency power �8 ms² ( HR �3.8; 95% CI �1.5–10.1; P�0.007) and troponin �0.3 ng/mL (HR �4.0; 95% CI �1.3–12.1; P�0.016) revealed that each contributed independently in predicting mortality. Nonlinear HRV variables were significant predictors of both outcomes.

Conclusion: HRV measured close to the ACS onset may assist in risk stratification. HRV cut-points may provide additional, incremental prognostic information to established assessment guidelines, and may be worthy of additional study.

Rights

Copyright © 2013 Dovepress.

PubMed ID

25143740

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License