The Use of Cluster Analysis to Assess the Frequency Indexes of Heart Rate Variability in Patients with Stable Angina

The aim of the investigation is to study the frequency indexes of heart rate variability (HRV) in three stages of stress test with physical exercise in patients with stable angina and to determine the peculiarities of their vegetative responsiveness according to cluster analysis findings. Materials and methods. Stress test with physical exercise showed the dynamics of HRV normalized spectral indexes and the peculiarities of autonomic nervous system (ANS) responsiveness during the stress test with physical exercise in 121 patients with congestive heart failure (chf) with various degrees of coronary involvement and 14 conditionally healthy people. All the patients had positive results of stress test with physical exercise using bicycle ergometer and coronary angiography findings. Results. The capacity of HRV low- and high-frequency indexes depending on coronary atherosclerosis intensity using cluster analysis was assessed. The relationship between HRV normalized spectral indexes and the severity of coronary involvement was revealed. The functional dynamic principle of vegetative regulation examination during the stress test with physical exercise is prospective to comprehend the interacting processes of sympathetic and parasympathetic parts of ANS and can be used for prognosis of coronary atherosclerosis severity in CHF patients.