[Use of fourier row as a method for analyzing the course of circadian heart rate in patients with left ventricular ejection fraction impairment].

The circadian heart rate course was assessed in 3 groups of patients with left ventricular ejection fraction (LVEF) 10-15%, 20-25% and 30-35%. The study comprised 36 persons. In 9 patients heart failure was due to MI and in 17--to dilated cardiomyopathy. Those with atrial fibrillation, ventricular tachycardia, supraventricular tachycardia, diabetes, valvular heart diseases and with central system disorders were excluded from the study. Left ventricular ejection fraction was evaluated by echocardiography. Heart rate, calculated as a mean value every 5 minutes, was taken in patients during 24 hour recordings. For each patient separately, mean value of all measurement was calculated. Then a ratio of each actual value to the mean value was calculated. This ratio was defined as relative heart rate; [formula: see text] Circadian heart rate courses were approximated by Fourier row: [formula: see text]. The 24 harmonics were analyzed. Statistically significant differences in circadian courses were closed to amplitudes of 1st, 12th, 13th, 14th, 16th, 18th harmonics. Using test of variance homogeneity it has been demonstrated that variability of amplitudes of 12th and 17th harmonics as well as phase of 5th harmonic depend on left ventricular ejection fraction.