Abstract 13388: Autonomic Balance And Mental Stress-induced Myocardial Ischemia
Introduction: Although mental stress-induced myocardial ischemia (MSIMI) has been linked to adverse cardiovascular outcomes, its underlying mechanisms remain to be elucidated. We assessed whether autonomic dysfunction was important in precipitating MSIMI with the hypothesis that autonomic function, estimated using heart rate variability (HRV), will be associated with MSIMI.
Methods: We examined autonomic function at rest in 168 patients with CAD using the ANSAR method (ANX 3.0, ANSAR Inc. Philadelphia, PA). Sympathetic and parasympathetic tone were assessed using low (LFa) and respiratory (RFa) frequency HRV that was adjusted for respiration using continuous wavelet transform. Sympathovagal balance was calculated as the ratio of LFa/RFa. Patients underwent 99mTc sestamibi myocardial perfusion imaging during both mental stress testing using a public speaking task, and, as a control condition, with conventional (pharmacologic or exercise) stress testing. Ischemia was defined as a new or worsening impairment in myocardial perfusion within each myocardial segment using a 17-segment model.
Results: In our population, (age 63 ± 9 years, 70% men), 11% developed MSIMI and 28% developed conventional stress-induced myocardial ischemia (CSIMI). Patients with MSIMI had higher sympathetic tone and increased sympathovagal balance [median (IQR) LFa of 1.1 (0.4-8.2) vs 0.6 (0.3-1.1) bpm2, p=0.017 and LFa/RFa of 1.7 (0.8-3.6) vs 1.0 (0.6-2.0), p=0.02] but not parasympathetic activity [RFa of 0.8 (0.3-2.9) vs 0.5 (0.2-1.3) bpm2, p=0.29] compared to those without MSIMI. Patients with increased LFa/RFa ratio had significantly higher risk of MSIMI [3rd vs 1st tertile OR(95%CI) of 4.4 (1.1 - 17), p=0.03], that remained significant after adjustment for CAD risk factors, beta blockers, rate pressure product and CSIMI. No correlation was found between LFa, RFa or LFa/RFa HRV and CSIMI.
Conclusion: Increased resting sympathovagal balance is associated with increased risk of MSIMI but not CSIMI. This suggests that chronic autonomic imbalance with increased symptathetic tone may be an important factor in the pathogenesis of MSIMI, and may have implications on potential therapies.
- Vascular disease
- Heart rate/Heart rate variability
- Cardiovascular disease
- Autonomic nervous system
Author Disclosures: A. Alkhoder: None. M. Hammadah: None. A. Shah: None. I. Al Mheid: None. K. Wilmot: None. R. Ramadan: None. M. Obideen: None. N. Abdelhadi: None. N. Isakadze: None. M. Awad: None. I. Ibeanu: None. H.M. Kelli: None. O. Levantsevych: None. M. Kutner: None. L.H. Shallenberger: None. N. Murrah: None. B. Pearce: None. D. Bremner: None. V. Vaccarino: None. A.A. Quyyumi: None.
- © 2016 by American Heart Association, Inc.