ABSTRACT
Symbolic dynamics derived from heart rate variability (HRV) is able to reflect changes of cardiac autonomic modulations on short time scales in spite of the considerable reduction of information involved. However, the link between the appearance of specific symbolic patterns and the activity of the autonomic nervous system has not yet been elucidated. In this study, we investigate the symbolic dynamics that reflect acceleration (='1') and deceleration (='0') of the instantaneous heart rate. The resulting binary series is analyzed with respect to the regularity of binary patterns of length 8 using Approximate Entropy (ApEn). Binary patterns were grouped according to the level of their regularity as assessed by ApEn. ECG recordings were obtained from 17 healthy subjects during graded head-up tilt (0, 15, 30, 45, 60, 75, and 90°). The linear correlation (Spearman correlation coefficient) between tilt angle and the occurrence of binary patterns was evaluated. The results show that regular binary patterns occurred more often with increasing tilt angle whereas the occurrence of some irregular patterns decreased. Some binary patterns did not show a change of occurrence during tilt. When compared to the results of spectral analysis, regular binary patterns reflect sympathetic modulations whereas irregular binary patterns reflect parasympathetic modulations. The parameters derived from binary symbolic dynamics reflect changes of autonomic modulations during graded head-up tilt and are not fully correlated to the spectral markers of HRV.
Subject(s)
Heart Rate/physiology , Models, Cardiovascular , Pattern Recognition, Automated/methods , Posture/physiology , Adult , Autonomic Nervous System/physiology , Electrocardiography , Female , Humans , Linear Models , Male , Middle AgedABSTRACT
AIMS OF THE STUDY: The aim of this study was to investigate the relevance and the barriers of physician empathy in medical rehabilitation by conducting a narrative literature review and a qualitative survey in physicians. METHODS: First, we described the current state of research of physician empathy in medical rehabilitation based on a narrative (non-systematic) review of the literature. Additionally, the questions of relevance and barriers of physician empathy were examined in a qualitative short survey with physicians from Rehabilitation Medicine, Internal Medicine, Pediatric and Family Medicine. The qualitative data were analyzed according to the summarizing content analysis of Mayring. RESULTS: Only n=13 studies of physician empathy were conducted in Rehabilitation Medicine; of those, just a few were from Germany and a small number investigated the influence of empathy on patient health outcomes. The qualitative survey's results regarding the definition, patient outcomes and barriers of physician empathy are similar to other theoretical and empirical studies on those issues. Moreover, they show many new, practical aspects, particularly in the field of barriers of physician empathy. CONCLUSION: Although physician empathy has been shown to be an outcome-relevant factor in acute health care, less attention has been paid to it in Rehabilitation research. Physicians from Rehabilitation Medicine, Internal Medicine, Pediatric and Family Medicine perceive empathic behavior also as an outcome-relevant ability, which is particularly hindered by time pressure and stress but also by personal and patient-specific factors.
