Mental Stress-induced Myocardial Ischemia In Patients Research Articles

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

Mental stress-induced myocardial ischemia (MSIMI) is associated with adverse cardiovascular outcomes in individuals with coronary artery disease, but the mechanisms underlying this phenomenon are unknown. We examined the relationship between stress-induced autonomic dysfunction, measured by low heart rate variability (HRV) in response to stress, and MSIMI in patients with stable coronary artery disease. We hypothesized that stress-induced autonomic dysfunction is associated with higher odds of MSIMI. In 735 participants with stable coronary artery disease, we measured high- and low-frequency HRV in 5-minute intervals before and during a standardized laboratory-based speech stressor using Holter monitoring. HRV at rest and stress were categorized into low HRV (first quartile) versus high HRV (second to fourth quartiles); the 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. The mean age was 58 (SD, ±10) years, 35% were women, 44% were Black participants, and 16% developed MSIMI. Compared with high HRV during stress, low HRV during stress (both high and low frequencies) was associated with higher odds of MSIMI after adjusting for demographic and clinical factors (odds ratio for high-frequency HRV, 2.1 [95% CI, 1.3-3.3]; odds ratio for low-frequency HRV, 2.1 [95% CI, 1.3-3.3]). Low-frequency HRV at rest was also associated with MSIMI but with slightly reduced effect estimates. In individuals with coronary artery disease, mental stress-induced autonomic dysfunction may be a mechanism implicated in the causal pathway of MSIMI.

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

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.

Abstract 18514: The Degree of Microvascular Constriction During Mental Stress Predicts the Development of Mental Stress-Induced Myocardial Ischemia

Introduction: Mental stress-induced myocardial ischemia (MSI) has been linked to a higher rate of fatal and non-fatal cardiac events in patients with CAD, independent of traditional cardiovascular risk models. Coronary vascular constriction with mental stress is a potential mechanism of MSI that may be reflected as constriction in the peripheral circulation. Moreover, peripheral arterial constriction may itself contribute to MSI by increasing afterload. Hypothesis: We hypothesized that a more pronounced microvascular constrictor response to mental stress will be predictive of development of MSI. Methods: Patients with stable CAD (n=116) underwent a standardized mental stress test using a public speaking task. Myocardial perfusion imaging with 99m-Tc-sestamibi was used for rest and stress images. MSI was defined as a summed difference score of ≥4, based on the difference between summed stress and rest perfusion scores. Peripheral arterial tonometry (PAT) was used to assess peripheral microvascular function during rest and mental stress. The PAT response was calculated as a ratio of the lowest pulse wave amplitude during the speaking task to the final three minutes of pulse wave amplitude during baseline rest. Univariate and multivariate logistic regression models were used to assess the association between PAT response and MSI. Models were adjusted for established CAD risk factors, and medications. Results: Patients with MSI (n=16, 14%) had a significantly lower PAT ratio than those without MSI (0.49 ±0.26 vs. 0.72± 0.34, p=0.01). Furthermore, the PAT response during mental stress was an independent predictor of the development of MSI, even after adjusting for aforementioned covariates (p=0.01). The peak rate-pressure product and diastolic BP during speech were similar in those with or without MSI (13580±4873 vs. 12947±2914, p=0.5; and 101±14 vs. 99±12, p=0.6, respectively). Systolic BP, diastolic BP, and heart rate changes from rest to speech were similar in those with and without MSI. Conclusion: The degree of peripheral microvascular constriction in response to mental stress predicts the risk of developing MSI in patients with stable CAD. Whether the PAT response during mental stress portends a worse long term prognosis needs to be investigated.

Mental stress–induced myocardial ischemia in coronary artery disease patients with left ventricular dysfunction

Reduced left ventricular ejection fraction (LVEF) is a risk factor for poor outcomes in patients with coronary artery disease (CAD). Mental stress-induced myocardial ischemia (MSIMI) also identifies a subset of CAD patients at increased risk for future cardiovascular events. Susceptibility to MSIMI in patients with CAD and reduced LVEF is unknown. We enrolled 182 patients (67 women) with a mean age of 64 years and a documented history of CAD in this study. Baseline resting ejection fraction was determined by use of technetium 99m sestamibi gated single photon emission computed tomography. Abnormal LVEF was defined as less than 45% for men and less than 50% for women (based on published norms for our software [Cedars-Sinai Medical Center]). All participants underwent mental stress testing with a public speaking task. Rest/stress myocardial perfusion single photon emission computed tomography was performed via conventional methodology. Images were visually compared for number and severity of perfusion defects by use of a scoring method from 0 to 4. A summed difference score was calculated as the difference between summed stress and rest scores. A score of greater than 3 was considered abnormal. MSIMI developed in 19% of patients with normal LVEF and 31% of those with reduced LVEF. There is no statistically significant difference between the two groups (P = .11). CAD patients with left ventricular dysfunction are equally susceptible to MSIMI as those with normal LVEF.