Abstract P241: Stress-Induced Autonomic Dysfunction is Associated With Mental Stress-Induced Myocardial Ischemia in Patients With Coronary Artery Disease

Abstract

Background: Mental stress-induced myocardial ischemia (MSIMI) is associated with adverse cardiovascular outcomes in individuals with coronary artery disease (CAD), but the mechanisms underlying this phenomenon are unknown. We examined the relationship between stress-induced autonomic dysfunction, measured by lower heart rate variability (HRV) in response to stress, and MSIMI in patients with stable CAD. We hypothesized that stress-induced autonomic dysfunction is associated with higher odds of MSIMI. Methods: In 735 participants with stable CAD, we measured high frequency (HF) and low frequency (LF) HRV in 5-minute intervals before and during a standardized laboratory-based speech stressor using Holter monitoring. MSIMI was evaluated with single-photon emission computed tomography myocardial perfusion imaging. HRV at rest and stress were categorized into low (lowest quartile) versus high (upper three quartiles) categories; low category was used as an indicator of autonomic dysfunction. Multivariable logistic regression models were used to examine the association of autonomic dysfunction with MSIMI. Results: The mean age was 58 (SD ±10) years, 35% were women, 44% were Black participants, and 16% developed MSIMI. Compared with high stress HRV, low stress HRV (both HF and LF) was associated with higher odds of MSIMI after adjusting for demographic and clinical factors. LF HRV at rest was also significantly associated with MSIMI with slightly reduced effect estimates. Conclusions: In individuals with CAD, mental stress-induced autonomic dysfunction may be an independent mechanism in the pathogenesis of MSIMI.