Episodes of acute heart rate variability decrease in coronary heart disease patients and healthy people at normal levels of physical stress

Abstract

Aim. To study the episodes of acute heart rate variability (HRV) decrease in patients with coronary heart disease (CHD) and healthy people, at normal levels of physical stress (PS) – stairs climbing.
Material and methods. The study included 30 patients with CHD, who underwent coronaroangiography, and 17 relatively healthy people (control group). Non-stop ECG monitoring was performed during stairs climbing at normal pace.
Results. Episodes of acute HRV decrease were registered in 29 CHD patients and 12 healthy people. In CHD patients, the episodes developed at lower PS and HR levels, than in healthy subjects, regardless of compromised vessels’ number and stenosis severity. HR at the start of HRV decrease episode was 50% from submaximal HR in patients with unstable angina; 64% - in patients with stable angina, and 87% - in healthy individuals.
Conclusion. Moderate PS test helped to identify, by registering episodes of acute HRV decrease, CHD patients and healthy people. Ratio “HR at the start of the episode” / “Submaximal HR” (HR LF<40 ms2 / HR submax) in patients with unstable angina was significantly lower than in individuals with stable angina.