Author/Editor		Kališnik, Jurij-Matija
Title		Primerjava kazalcev variabilnosti srčne frekvence pri bolnikih s prizadetimi venčnimi arterijami pred in po operaciji aortokoronarnih premostitev
Type		monografija
Place		Ljubljana
Publisher		Medicinska fakulteta
Publication year		2000
Volume		str. 35
Language		slo
Abstract		Background: Indexes of heart rate variability (HRV) provide information about sympathovagal balance rendering the insight into mechanisms of its maintenance in various disease states. Cardiac vagal modulation is reduced in patients with coronary artery disease or previous myocardial infarction. The propensity to lethal arrhythmias is thus increased. The highest vagal modulation in coronary artery has been gained by adopting right recumbent position. The studies reporting on HRV in the immediate postoperative period show considerable inconsistency. Moreover, no attempt has been made to determine HRV according to the assumed various lying positions or comparing two different operative procedures, namely conventional and beating heart surgery. Methods: Seven female and twenty-five male subjects, mean age 62.6+-8 yr. enrolled in the study. Electrocardiograms and respiratory waveform signals were recorded for 10 minutes by means of newly developed DEKG recording device. Power spectra were computed from 5-minute stable RR intervals using Fast Fourier Transform analysis (FFT). Normalized high frequency power (nHF) indicated cardiac vagal modulation; normalised low frequency power (nLF) indexed sympathetic baroreflex modulated activity. To verify the normal distribution of data, log power spectra were calculated by taking the natural logarithm of the power spectra of each component. The results of power spectral measurements were further analyzed using paired and non-paired t-tests, p<0.05 considered significant. Results: Total power an the powers in HF, LF and nHF range were significantlly higher when lying supine on fourth and seventh day, respectively (p<0.05). RR interval shortened significantly immediately after the operation (aproximately by one fourth). TP, HF and LF were depressed markedly after operation, showing significant secondary reduction on seventh day as compared to the first and second postoperative day (p<0.05). (Abstract truncated at 2000 characters).
Descriptors		CORONARY DISEASE HEART RATE CORONARY ARTERY BYPASS ELECTROCARDIOGRAPHY SPECTRUM ANALYSIS AUTONOMIC NERVOUS SYSTEM VAGUS NERVE DIAGNOSIS, COMPUTER-ASSISTED FOURIER ANALYSIS