Effects of Cardiac Rehabilitation With Lumbar-Type Hybrid Assistive Limb on Muscle Strength in Patients With Chronic Heart Failure　- A Randomized Controlled Trial.

BACKGROUND: Aiming to establish an effective tool in new cardiac rehabilitation programs, we investigated the use of a lumbar-type hybrid assistive limb (HAL) in patients with heart failure (HF) who had difficulty in walking at the usual speed of healthy subjects (≈80 m/min).Methods and Results:We randomly assigned 28 HF patients (age, 73.1±13.8 years) to perform a sit-to-stand exercise with or without HAL. The sit-to-stand exercise was repeated as many times as possible as cardiac rehabilitation therapy over a period of 6-10 days. We measured 5 parameters before and after the completion of cardiac rehabilitation: B-type natriuretic peptide, Short Physical Performance Battery (SPPB), 6-min walking distance (6MWD), 30-s chair-stand test (CS-30), and isometric knee extensor muscle strength. The SPPB and 6MWD were significantly improved, and the CS-30 score was somewhat improved, after the exercise therapy in both the HAL and non-HAL groups. The knee extensor muscle strength improved significantly in the HAL group (0.29±0.11 to 0.35±0.11 kgf/kg, P<0.01), but showed no change in the non-HAL group (0.35±0.11 to 0.35±0.13 kgf/kg, P=0.40). CONCLUSIONS: The improved knee extensor muscle strength in the HAL group suggests that the lumbar-type HAL may be an effective tool for cardiac rehabilitation in HF patients with frailty, which is a predictor of poor prognosis in HF.

Efficacy of Cardiac Rehabilitation with Assistance from Hybrid Assistive Limb in Patients with Chronic Heart Failure: Protocol for a Randomized Controlled Study.

The hybrid assistive limb (HAL) provides motion assistance based on bioelectrical signals detected on the skin surface when muscle forces are generated. The lumbar-type HAL is expected to expand the therapeutic options for severe cardiac patients who have difficulty in moving on their own legs. We aim to compare the efficacy of exercise therapy performed with assistance from a lumbar-type HAL versus conventional training (sit-to-stand exercise without HAL) in patients with chronic heart failure. This investigation will be a randomized, nonblinded, controlled study. Sixty patients who satisfy the criteria to receive cardiac rehabilitation therapy under the Japanese national insurance system will be enrolled at the University of Tsukuba Hospital. Participants randomly assigned to 2 groups (HAL group and conventional group) at a 1:1 allocation ratio will perform exercise therapy either with HAL or without HAL for 5-30 min once a day for 6-10 days. Outcome parameters will be measured just before and after the completion of the exercise therapy and at 1 year after hospital discharge. The primary outcomes will be the heart rate, blood pressure, subjective ratings of exercise intensity during exercise (Borg scale), number of days from the start of exercise therapy to independent walking and to discharge, and prognosis (mortality and cardiovascular events) over the 1-year period after discharge. The secondary outcomes will be the assessment of heart failure severity, brain natriuretic peptide, grip strength, thigh muscle thickness, isometric knee extensor strength, standing ability, 10-meter walking speed, 6-min walking distance, short physical performance battery, and adverse events. Unpaired t tests will be used for baseline assessments and outcome measures. This is the first randomized controlled study to examine the efficacy and feasibility of lumbar-type HAL in patients with chronic heart failure. If the results confirm beneficial effects in the outcomes of patients with heart failure, this study will add more evidence in support of the use of the lumbar-type HAL as an effective tool in new cardiac rehabilitation programs.

Effects of a cyborg-type robot suit HAL on cardiopulmonary burden during exercise in normal subjects.

BACKGROUND: The hybrid assistive limb (HAL) is the world's first cyborg-type robot suit that provides motion assistance to physically challenged patients. HAL is expected to expand the possibilities of exercise therapy for severe cardiac patients who have difficulty in moving on their own legs. As a first step, we examined whether or not the motion assistance provided by HAL during exercise could effectively reduce the cardiopulmonary burden in healthy subjects. METHODS: A total of ten healthy male adults (35 ± 12 years) underwent cardiopulmonary exercise testing (CPX) on a cycle ergometer with or without assistance from HAL. The CPX protocol consisted of four 3-min stages performed in a continuous sequence: rest, 0 W, 40 W, and 80 W. The heart rate (HR), blood pressure, oxygen uptake (VO2), minute ventilation (VE), and gas exchange ratio (R) were monitored during the CPX. RESULTS: At 0 W, the HR, VO2, and VE were significantly higher when HAL was used. At 80 W, however, the HR (107 ± 14 vs 114 ± 14 beats/min, p < 0.01), systolic blood pressure (141 ± 15 vs 155 ± 20 mmHg, p < 0.01), VO2 (17.6 ± 2.4 vs 19.0 ± 2.5 mL/min/kg, p < 0.05), and R (0.88 ± 0.04 vs 0.95 ± 0.09, p < 0.05) were significantly lower when HAL was used. CONCLUSIONS: HAL has the potential to reduce cardiopulmonary burden during moderate-intensity exercise and can, therefore, be used as a support for exercise therapy. Further studies on cardiac patients are expected to contribute to the establishment of a new exercise therapy program using HAL.

Safety and efficacy of in-hospital cardiac rehabilitation following antiarrhythmic therapy for patients with electrical storm.

BACKGROUND: Exercise-based in-hospital rehabilitation for patients with electrical storm (ventricular tachycardia/ventricular fibrillation, VT/VF) following antiarrhythmic therapy may prevent the deleterious outcomes of prolonged immobility, but the safety and efficacy of this strategy are still uncertain. We retrospectively investigated the rate of electrical storm recurrence in patients receiving rehabilitation. METHODS: Sixty-seven patients receiving therapy for electrical storm were included in this study. After treatment, patients were divided into rehabilitation (n=39) and non-rehabilitation (n=28) groups. RESULTS: Incidences of electrical storm recurrence and VT/VF requiring anti-tachycardia pacing or electrical defibrillation did not differ significantly between the rehabilitation and non-rehabilitation groups (13% vs. 21% and 28% vs. 25%, respectively). However, early mobilization initiated ≤2 days after primary therapy was disadvantageous for electrical storm and VT/VF recurrence compared to later mobilization (21% vs. 6% and 34% vs. 19%, respectively). Although the activities of daily living (ADL) at admission were significantly lower in the rehabilitation group, the scores were restored to the level of the non-rehabilitation group at the time of discharge. Univariate analysis revealed that high B-type natriuretic peptide (hazard ratio [HR]: 3.2; 95% confidence interval [CI]: 1.1-11), decreased left ventricular ejection fraction, and elevated E/E' (HR: 3.4; 95% CI: 1.1-11) were associated with VT/VF recurrence. CONCLUSIONS: The incidence of electrical storm relapse is substantial following antiarrhythmic therapy, but it is not increased by in-hospital rehabilitation. Although caution is urged for early mobilization, sustaining mobility to resume activity is recommended because ADL levels tend to deteriorate as a result of prolonged bed rest.

Effects of a lumbar-type hybrid assistive limb on cardiopulmonary burden during squat exercise in healthy subjects.

The lumbar-type Hybrid Assistive Limb (HAL) is expected to expand the possibilities of exercise therapy for severe cardiac patients who have difficulty in moving on their own legs. We investigated whether motion assistance from HAL during squat exercise could effectively reduce the cardiopulmonary burden in healthy subjects. Twelve healthy subjects (33 ±â€¯11 years) performed squat exercise for 3 consecutive minutes at a repetition rate of 20 squats per minute with and without assistance from a lumbar-type HAL. The oxygen uptake (VO2), carbon dioxide output (VCO2), minute ventilation (VE), and the Borg Scale were monitored during exercise. VO2 (930 ±â€¯207 vs 992 ±â€¯169 mL/min, p < 0.05) and the Borg Scale rating (12.8 ±â€¯1.1 vs 13.7 ±â€¯0.8, p < 0.05) at the end of exercise were significantly lower when HAL was used. When 2 subjects who regularly perform high-intensity exercise for more than 10 h per week were excluded from the analyses, VO2, VCO2, VE, and the Borg Scale were significantly lower when HAL was used. Our results demonstrate that the lumbar-type HAL significantly reduces cardiopulmonary burden during squat exercise in healthy subjects. The effects were especially striking in sedentary subjects. Further studies on cardiac patients are expected to establish a new cardiac rehabilitation program using HAL.