[Individualization of exercise load control for inpatient cardiac rehabilitation. Development and evaluation of a HRV-based intervention program for patients with ischemic heart failure]. / Individualisierung der Belastungssteuerung in der kardiologischen stationären Rehabilitation. Entwicklung und Evaluation eines HRV-gesteuerten Interventionsprogramms für Patienten mit ischämisch bedingter Herzinsuffizienz.

BACKGROUND: The effective use of rehabilitation programs is of primary importance in order to improve the physical performance of cardiac disease patients. A modular program has been developed which is intended to structure and individualize conventional, exercise-based rehabilitation programs according to the individual needs and physical condition of each patient. The individualization of the program is based on detailed diagnostics before patients enter the program and daily measurements of heart rate variability (HRV) during cardiac rehabilitation. METHODS: A total of 30 patients with ischemic heart disease were randomly assigned either to the intervention group (IG), completing the modular individualized rehabilitation program [n=15, mean age 54.4±4.2 years and mean left ventricular ejection fraction (LVEF) 28.53±6.25%) or to the control group (CG) taking part in the conventional rehabilitation program (n=15, mean age 56.4±4.4 years and mean LVEF 27.63±5.62). Before and after the intervention, cardiorespiratory fitness was assessed by measurement of maximal oxygen consumption (relative VO2max) during bicycle ergometry and the 6-minute walk test (6-MWT). Pre-post comparisons of cardiorespiratory fitness indicators were used to evaluate the effectiveness of the rehabilitation program. In addition to the results of the basic clinical investigations and the cardiorespiratory testing, results of standardized HRV measurements of 10 min at morning rest served as criteria for program individualization. RESULTS: The relative VO2max increased significantly (p<0.05) in the IG whereas no change was found in the CG. Similar results were found for maximum power output during bicycle ergometry (p<0.01) and for 6-MWT distance (p<0.001). Although patients in the IG completed less aerobic exercise sessions than those in the CG (p<0.001) the physical performance of the IG improved significantly. DISCUSSION: The results prove the effectiveness and efficacy of the modular individualized rehabilitation program. They further suggest the need for an individual program matrix instead of a maximum performance matrix in cardiac rehabilitation. Individualization should be based on clinical and performance diagnostics before and accompanying assessments of training condition, e.g. by HRV measurements, during rehabilitation programs. Each patient should only perform those intervention programs which match the results of the basic clinical investigation and additional analyses during rehabilitation.