Low-frequency heart rate variability: reproducibility in cardiac transplant recipients and normal subjects

Abstract

Heart rate variability is a measure of autonomic nervous influence on the heart. It has been suggested that it could be used to detect autonomic reinnervation to the transplanted heart, but the reproducibility of the measurement is unknown. In the present study, 21 cardiac transplant recipients and 21 normal subjects were recruited. Three measurements of heart rate variability were performed during the day: in the morning, in the early afternoon and in the late afternoon. These tests were then repeated 1 week later and then again 1 week after that, making nine tests in all. The within-subject S.D. was 0.49 log units in normal subjects and 0.79 log units in transplant recipients. In both cases, this is about 15% of the population range. There was significant variation in heart rate variability between different times of day in both groups, and from day to day in transplant recipients. It was concluded that the reproducibility of measurements of heart rate variability is low, and that differences between measurements performed at different times of day should be interpreted with caution.

Reproducibility of heart rate variability parameters measured in healthy subjects at rest and after a postural change maneuver

“…However, additional studies are necessary to determine if these findings are demonstrable in subjects with diseases that cause disturbances of the autonomic nervous system. Unlike other studies (22,27), our results indicate that intra-individual measurements can show good reproducibility, even for short-time recordings in the supine position if external factors that alter autonomic balance are well controlled. Thus, studies questioning reproducibility use different ECG recording sequences.…”

“…Since it is a noninvasive and inexpensive method, several recordings can be easily obtained as a function of time in the same individual to evaluate the efficacy of therapeutic interventions. Therefore, some studies have been specifically designed to evaluate the reproducibility of the measurements since autonomic balance is subjected to a large number of central and peripheral control systems, all of them potentially affecting HR control (17)(18)(19)(20)(21)(22)25). Some studies have shown good reproducibility in HRV analysis (17,20,21), while others have reported the opposite (22,27).…”

“…Therefore, determination of HRV reproducibility is a key question in longitudinal studies or in clinical conditions, where the same data are recorded from a single individual at different times. Although several studies have found an adequate reproducibility of HRV both in the time and in the frequency domain analyses (13)(14)(15)(16)(17)(18)(19)(20)(21)(22), others have not made this observation (22,23). However, reproducibility of the different components of spectral HRV obtained from short-term records is still under discussion (24,25).…”

“…Thus, studies carried out on healthy individuals have shown good reproducibility of temporal parameters when www.bjournal.com.br Braz J Med Biol Res 43(10) 2010 records were obtained within short (<24 h) and long (>24 h) recording periods (18,20,21,26). However, even with long recordings, reproducibility has been questioned in relation to spectral parameters (22,(27)(28)(29). In short-term recordings (5-10 min) reproducibility increases when breathing periodicity is externally controlled (18).…”

“…Previous studies on intra-indivudual reproducibility of HRV have been conducted with subjects in the classical supine position (17,22,26). Since this exam sometimes is also carried out during postural maneuver (tilt-test for example), we compared the reproducibility of temporal and spectral HRV indexes of a group of healthy individuals in the supine and orthostatic positions using short-term recording periods under spontaneous breathing.…”