Relationship between Heart Rate Turbulence and Heart Rate Variability in Korean Adults with Structurally Normal Heart

Background and Objectives:Heart rate variability (HRV) illustrates the autonomic integration of the heart. Depressed HRV has been proven to be associated with an increased risk of cardiac death, whereas heart rate turbulence (HRT) is believed to reflect baroreflex sensitivity and it was recently introduced as another noninvasive tool for risk stratification. The aim of this study was to determine the relationship between the HRT and HRV parameters in Korean adults with a structurally normal heart. Subjects and Methods:We studied 61 adults (males: 31) who showed ventricular premature complexes on 24 hour Holter recording and who were found to have normal hearts on full noninvasive investigation. We calculated the mean heart rate (RR interval), the number of VPBs, the timeand frequency-domain HRV parameters and two HRT parameters: turbulence onset (To) and turbulence slope (Ts). Results:Ts showed a strong correlation with the HRV parameters (LF/HF ratio: r=0.35, p=0.006; VLF: r=0.32, p=0.013; LF: r=0.27, p=0.035; SDNN: r=0.28, p=0.029; SDANN: r=0.32, p=0.012), but To showed no significant correlation with the HRV parameters. Conclusion:The HRT parameters, and especially Ts, correlate strongly with the HRV parameters; therefore, Ts should be considered as a parameter that reflects the overall cardiac autonomic tone. (Korean Circulation J 2006;36:126-132)