Abstract 18264: Heart Rate Variability Predicts Mental Stress Ischemia in Patients With Stable Coronary Artery Disease
Introduction: Mental stress ischemia (MSI) is an independent risk factor for cardiovascular outcomes and death in CAD patients, but little is known about the mechanisms behind this phenomenon. We hypothesized that alterations in autonomic function before, during, or after mental stress may play a role. We examined whether MSI positive patients with CAD have reduced parasympathetic (PNS) tone, as measured by high frequency heart rate variability (HF HRV), as well as reduced baroreceptor sensitivity (BRS), as approximated by low frequency (LF) HRV at baseline, peak mental stress, and recovery.
Methods: A mental stress test with a standardized speech stressor was performed in 425 CAD patients wearing an ambulatory ECG monitor. Myocardial perfusion imaging was performed with TC-99m Sestamibi. After careful editing for artifacts and ectopic beats, HF HRV and LF HRV were measured for 5-min periods during a baseline rest period, 5 min of speech, and 5 min of recovery. Logistic regression was used to adjust for potential confounders.
Results: The mean (SD) age was 63 (9) years, 26% were women, and 30% were African American; 42 (10%) patients developed MSI. Compared with MSI negative, MSI positive patients had lower HF HRV and LF HRV during rest, stress, and recovery. The largest difference was observed during stress; HF HRV was 46% lower (p=0.01), and LF HRV was 44% lower (p=0.01). When examining reactivity to stress (difference between stress and rest), only LF HRV was significantly different between groups, such that MSI positive patients had an average 32% reduction in LF HRV with stress, while MSI negative patients had an average 3% increase (p=0.04). LF HRV reactivity remained an independent predictor of MSI (p=0.01) in models adjusting for sociodemographics, traditional risk factors, antidepressants, beta-blocker use, revascularization history, heart failure, depression, posttraumatic stress disorder, and heart rate/blood pressure reactivity.
Conclusions: Autonomic factors, most notably reduced LF HRV reactivity, predict MSI in CAD patients. This implies reduced BRS and autonomic inflexibility as an important pathophysiological component of the ischemic response to mental stress.
Author Disclosures: A.J. Shah: None. A.A. Quyyumi: None. M. Kutner: None. J.D. Bremner: None. E. Garcia: Ownership Interest; Modest; Emory Toolbox. J. Nye: None. K. Wilmot: None. I. Al Mheid: None. A. Alkhoder: None. N. Isakadze: None. M. Obideen: None. N. Abdelhadi: None. B. Pearce: None. Q. Long: None. R. Lampert: None. P. Raggi: None. V. Vaccarino: None.
- © 2015 by American Heart Association, Inc.