Abstract 19396: Impaired Autonomic Modulation During the Valsalva Maneuver Predicts Ischemia in Patients With Coronary Artery Disease
Introduction: Previous studies have found that lower resting short-term heart rate variability (HRV), a measure of autonomic dysfunction, predicts adverse cardiac events. Abnormal autonomic function may precipitate myocardial ischemia. Physiologic challenges like Valsalva and deep breathing may also provide important data by modulating preload/afterload and stimulating various autonomic receptors.
Methods: We examined autonomic function in 166 patients with CAD using the ANSAR method (ANX 3.0, ANSAR Inc. Philadelphia, PA). HRV was measured in the sitting position, standing position, during deep breathing, and during Valsalva. After ANSAR testing, patients underwent 99mTc[[Unable to Display Character: ‐]]sestamibi myocardial perfusion imaging at rest and with exercise or pharmacological stress. A summed difference score (SDS) was computed to quantify ischemia using a 17-segment model with observer-independent software. Multivariable models adjusted for CAD risk factors, psychiatric comorbidities, and medications.
Results: The mean (SD) age was 62 (9) years, 75% were men, and 31% had ischemia (SDS ≥ 4). Both low (LF) and high (HF) frequency HRV during all 4 conditions were associated with ischemia in unadjusted models (table), but after multivariable adjustment, only LF and HF HRV during Valsalva and deep breathing were still associated with ischemia. The strongest association was found with LF HRV during Valsalva, such that every 10% decrease in LF HRV during Valsalva (p=0.003, adjusted) associated with a 1 point increase in SDS. When dividing patients into 4 categories of SDS score (0, 1-3, 4-7, ≥ 8), the SDS ≥ 8 category had a lower LF HRV during Valsalva than all other categories, most notably compared to SDS=0 (78% reduction in LF HRV).
Conclusion: Low HF and LF HRV are associated with increased risk of myocardial ischemia in CAD patients. Most notably, autonomic inflexibility during Valsalva may help uncover underlying vulnerabilities in autonomic reflexes that predict ischemia burden.
Author Disclosures: A.J. Shah: None. A. Alkhoder: None. M. Obideen: None. R. Ramadan: None. K. Wilmot: None. I. Al Mheid: None. M. Kutner: None. A.A. Quyyumi: None. J. Bremner: None. V. Vaccarino: None.
- © 2014 by American Heart Association, Inc.