A Comparison of Maximal Exercise Responses among Patients with a Total Artificial Heart, a Left Ventricular Assist Device, or Advanced Heart Failure
The purpose of this study was to evaluate graded exercise responses to treadmill exercise in patients with a total artificial heat (SynCardia, Tucson, AZ). Additionally, this study sought to compare the exercise response in total artificial heart (TAH) patients to both advanced heart failure (HF) patients on medical management only and HeartMate II (Thoratec Corp., Pleasanton, CA) left-ventricular assist device (HMII) patients. For patients with biventricular heart failure the TAH is a viable
... tion to bridge patients until transplant becomes available. Its demonstrated improvement in mortality and increasing usage necessitates a shift in focus to quality of life in the TAH patient including functional ability. The evaluation of cardiorespiratory responses to graded exercise provides an objective measure of functional ability. There is very limited information in the literature on the exercise response of the mechanical circulatory support (MCS) device patient, particularly the TAH patient. A review was performed on MCS patients who underwent symptom-limited cardiopulmonary exercise testing (CPET) following device implant of either TAH or HMII. ANOVA was performed to compare differences between the two device groups and HF patients listed for heart transplant. Fourteen TAH patients underwent CPET (9 male, 5 female) with peak oxygen consumption (V O 2 ) of 0.926 + .168 L•min, 36 + 8% % predicted, 11.0 + 2.3 ml.kg.min or 3.1 + 0.7 METs. Ventilatory anaerobic threshold (VAT) was 0.706 + .181 L•min. Peak V O 2, % pred. V O 2 and VAT were significantly lower in the TAH compared with HMII and advanced HF (p = 0.0012, p = 0.0106, p = 0.0009, respectively). Peak RER was significantly higher (p = <.0001) and OUES was significantly lower (p = 0.0004) in the TAH. Exercise capacity is significantly reduced in the TAH patient below that observed in HMII LVAD and advanced HF patients. This provides a baseline for expected functional status and has implications on the ADL tolerance of these individuals. The next step is to develop strategies to ameliorate this continued exercise intolerance. The documents herein contain a review of literature including a background in heart failure and the use of the exercise response in the heart failure patient. An overview is also presented on the use of MCS describing physiology, device function, and exercise physiology of the MCS device patient. A manuscript has also been included detailing a cross-sectional review of the effects of graded exercise in the TAH patient and comparing it to the HMII and advanced HF patient.