Autonomic and Hemodynamic Correlates of Daily Life Activity and Ambulatory Myocardial Ischemia in Patients with Stable Coronary Artery Disease
Abstract
Impaired autonomic-cardiac regulation, as defined by reduced levels of heart rate variability (HRV), is an independent predictor of death in patients with coronary artery disease (CAD) and a history of myocardial infarction. Moreover, transient shifts in HRV have been observed before the acute onset of ambulatory myocardial ischemia in CAD patients. The present study investigated whether or not changes in autonomic-cardiac regulation: (1) were associated with altered hemodynamic regulation in CAD patients; (2) could identify CAD patients at-risk for ambulatory myocardial ischemia; or (3) were related to changes in physical exertion and heart rate levels before the onset of ambulatory myocardial ischemia. Fifty-three patients with documented CAD (44 men; mean age 65 years) participated in 48-hours of ambulatory electrocardiographic (Holter), physical activity, and blood pressure monitoring. Holter tapes were analyzed for evidence of myocardial ischemia and were used to generate several indices of HRV, including markers for sympathetic and parasympathetic tone, and their ratio, sympathovagal tone. Results indicated that CAD patients with lower levels of HRV (n = 26) had significantly higher levels of heart rate than did patients with preserved levels of HRV (n = 27; p < .05), whereas HRV was found to be unrelated to patients blood pressure levels (p s > .05). Contrary to predictions, ischemic CAD patients (n = 9) were found to have significantly higher levels of HRV and significantly lower levels of heart rate when compared to non-ischemic patients (n = 44; p s < .05). These differences were not related to patients medication regimens, ejection fraction, or history of reperfusion procedures (p s > 05). Ischemic and non-ischemic CAD patients did not differ in terms of their HRV, heart rate, or blood pressure levels during prescribed non-ischemic periods of keepi
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 20, 2003
- Accession Number
- ADA421159
Entities
People
- John F. Quigley
Organizations
- Uniformed Services University of the Health Sciences