Abstract P201: Ischemia with Mental Stress is Associated with Greater Left Ventricular Dyssynchrony
Authors: Pratik M Pimple, Ernest V Garcia, Jonathon A Nye, Muhammad Hammadah, Ibhar Al Mheid, Kobina Wilmot, Ronnie Ramadan, Amit J Shah, Paolo Raggi, Fabio Esteves, Michael Kutner, Qi Long, Laura Ward, J. Douglas Bremner, Arshed A Quyyumi, Viola Vaccarino
Journal: Circulation (2016)

Introduction: Synchronized contraction of left ventricle (LV) is necessary for normal cardiac pump function. Delayed activation of LV segments, known as “dyssynchrony,” can result in systolic and diastolic function deterioration and clinical heart failure. The autonomic nervous system regulates LV conduction and is influenced by psychological stress. We used mental stress testing to examine the effects of psychological stress on LV dyssynchrony and assess whether patients who develop mental stress-induced myocardial ischemia (MSI), a condition associated with doubling of risk for mortality and cardiovascular events, have greater LV dyssynchrony at baseline and/or during stress as compared to MSI negative subjects. We compared results with a control condition of conventional physical (exercise/ pharmacological) stress. Methods: 660 patients with CAD underwent 99mTc[[Unable to Display Character: &amp;#8208;]]sestamibi myocardial perfusion imaging at rest and following both mental and physical stress. Dyssynchrony parameters, measured using the Emory Cardiac Toolbox software, included phase standard deviation (SD) and phase bandwidth; higher levels indicate higher desynchronized contraction. Ischemia with both conditions was blindly assessed by 2 independent readers, with consensus reading for any discordance. The Gensini score was calculated from angiographic data to assess CAD burden. Dyssynchrony data at baseline and during mental/physical stress were log-transformed for analyses. Results: Mean age was 63 years (SD: 9), 180 (27%) were females and 432 (66%) were whites. Overall, 108 (16%) subjects developed mental stress ischemia (MSI+), while 232 (35%) developed physical stress ischemia (PSI+). After adjusting for age, sex, race, traditional CAD risk factors, indicators of CAD burden, history of heart failure, and LV ejection fraction, at baseline MSI+ subjects compared with MSI- had 11% higher phase SD (95% CI: 1% to 19%), and 11% higher phase bandwidth (95% CI: 3% to 20%). PSI+ subjects compared with PSI- had a more modest and non-significant increase in phase SD (mean increase of 4%, 95% CI: -3% to 12%) and phase bandwidth (4%, 95% CI: -3% to 11%). The associations of MSI with baseline dyssynchrony was independent of PSI status. A similar association was noted between MSI and dyssyncrony during mental stress. Among the covariates, male sex (P=0.01), smoking (P=0.02), Gensini score (P=0.01), history of MI (P&lt;0.001), history of heart failure (P&lt;0.001), and LV ejection fraction (P&lt;0.001) were significantly associated with higher baseline dyssynchrony. Conclusion: MSI is associated with greater LV dyssynchrony at rest and during stress. Baseline LV dyssynchrony may be a marker of susceptibility to stress-induced ischemia possibly due to recurrent or chronic subclinical ischemia during daily life. LV dyssynchrony may be a potential mechanism for adverse cardiac events in patients with MSI.