Following implantation of a left ventricular assist device, the build-up and long-term maintenance of adequate exercise capacity and functional performance become crucial. The aim of this study was to observe the development of exercise-related values at different times, as well as to detect possible influencing factors. We performed a prospective single-centre study: 10 patients (63 years, 100% male, body mass index = 27.5, 100% HeartWare) underwent the following diagnostic tests during cardiac rehabilitation and during two subsequent ambulatory visits: 6-min walking test, handgrip strength test, cardiopulmonary exercise test and Minnesota Living with Heart Failure questionnaire. Mean follow-up was 482 days after left ventricular assist device implantation. Significant improvements could be observed between the end of cardiac rehabilitation and ambulatory visit 1; 6-min walking distance increased from 367 to 449 m (p < 0.01), peak VO2 from 10.0 to 11.9 mL/kg/min (p < 0.05) and peak load from 62.4 to 83.0 W (p < 0.01). However, there were no further improvements between ambulatory visit 1 and ambulatory visit 2. In the long term, a significant mean weight gain of more than 10 kg could be observed (p < 0.01). A negative linear correlation between weight gain and absolute improvement in peak load (r = −0.77, p < 0.01) and peak VO2 (r = −0.75, p < 0.05) could be demonstrated. In conclusion, exercise-related values following left ventricular assist device implantation initially improve significantly. Later, however, no further improvements can be observed. In the long term, pronounced weight gain is conspicuous, concomitant with a significantly lower increase in exercise values of the patients. In the future, both dietary and structured physical activity follow-up interventions should be integrated in patient routines.

Following implantation of a left ventricular assist device (LVAD), acceptable functional performance is now being achieved; however, peak VO and peak work load (watts) remain considerably limited. Maximum physical capacity is essentially dependent on generated cardiac output (CO) and arteriovenous oxygen difference (avDO ). We investigated the changes in CO and avDO during exercise in LVAD patients with an HVAD pump (HeartWare Inc., Framingham, MA, USA). Approximately 6 weeks after implantation, 20 patients (100% male, 60.8 ± 7.3 years old, BMI 25.7 ± 3.3) underwent a six-minute walk test (6MWT), a cardiopulmonary exercise test (CPET), and noninvasive hemodynamic measurement. The mean six-minute walking distance (6MWD) was 403 m (68% of predicted), and mean peak VO was 10.9 mL/kg/min (39% of predicted). Mean total CO improved from 3.8 L at rest to 7.0 L at maximum exercise. The mean avDO increased from 7.4 mL/dL (44% of oxygen content) at rest to 13.2 mL/dL (75% of oxygen content) at maximum exercise. There was a significant increase in both total CO (P < 0.01) and avDO (P < 0.05) between rest and sub-maximum exercise. As exercise levels increased, however, no further significant changes were achieved. Long-term studies, especially in combination with exercise programs, would be desirable in order to observe the development of these parameters.

In the course of time implantation of left ventricular assist devices (LVAD) has become an alternative to heart transplantation due to the enormous technical developments and miniaturization of these systems. Following implantation most patients show a significant improvement in their clinical condition and exercise capacity as measured by the New York Heart Association (NYHA) classification; nevertheless, exercise tolerance remains clearly limited even after LVAD implantation. The complex physiological and hemodynamic changes in LVAD patients both at rest and during exercise are ultimately not completely understood. The aim of this article is to describe the current state of scientific knowledge with respect to the physical capacity of patients with terminal heart failure after LVAD implantation at rest and during exercise. The influence of increasing the pump speed and continuous physical exercise training on the physical capacity in the long-term course is reviewed. The significance of new diagnostic tools, such as the non-invasive inert gas rebreathing method for measurement of cardiac output and arteriovenous oxygen difference (AVDO2) in assessment of the performance of LVAD patients is discussed.

In patients with left ventricular assist devices (LVAD), exercise capacity is a decisive factor regarding the quality of life. When evaluating exercise capacity, precise information about the total cardiac output generated is crucial. To date, complex measurements using a right-heart catheter were necessary in order to determine total cardiac output. The inert gas rebreathing method facilitates non-invasive, direct and valid measurement of total cardiac output as well as associated parameters, like the difference in arteriovenous oxygen saturation, both at rest and during exercise. It is the aim of this paper to focus on this conclusive method which is, despite its simplicity and low-risk reproducibility, rarely used within the framework of LVAD patient treatment at the present time. The test protocol used at our hospital is presented to facilitate the implementation of this helpful tool in other interested institutions.

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Funding Acknowledgements Type of funding sources: None. Purpose After orthotopic heart transplantation (HTX), patients benefit with improved survival and quality of life, but exercise physiology becomes complicated and exercise capacity usually remains limited at 60-70% of predicted values. However, there are also patients who return to demanding or competitive sports even after HTX. For these patients, optimal exercise hemodynamics and metabolisms are crucial. It was the aim of this study to investigate this question more closely in (very) sportive patients after HTX. Methods 6 patients after orthotopic HTX (1 female, 54±16 yrs old, BMI 23.6±2.8, 11±7 yrs post-transplant) from different sports disciplines (Cycling [2x], Triathlon, Hockey, Table-Tennis, Scuba Diving) could be included (Table 1). We performed cardiopulmonary exercise test (CPET) on a bicycle ergometer using a ramp protocol (15 watts/minute) and consecutive inertgas rebreathing (IGR) on different exercise steps (rest, light, moderate, heavy) of each 4-5 minutes. The hemodynamic measurements and blood gas analysis were conducted at the last minute of each IGR step. The study was approved by the local ethics committee. Results For CPET: one patient reached extraordinary exercise capacity with a peak load of 345 watts (182% of pred.) and a peak VO2 of 58.9 ml/kg/min (163% of pred.). Corresponding values at first ventilatory threshold (VT1) were 280 watts and 44.1 ml/kg/min. The results of the other patients showed a more homogenic profile: Mean peak load was 172±44 watts (104±14% of pred.) and peak VO2 was mean 25.6±4.5 ml/kg/min (91±14% of pred.). Values at VT1 were 108±27 watts and 18.0±2.5 ml/kg/min. Selected IGR results for all patients are displayed in Table 2. The hemodynamic measurements revealed a steadily increase in cardiac output (CO), cardiac index (CI), arteriovenous oxygen difference (avDO2), heart rate and systolic blood pressure from rest to the different exercise steps. However, an increase in stroke volume (SV) beyond light to moderate exercise often remained limited (peak SV 101±14 ml/beat). Also, peak CO (13.9±1.8 l/min) remained slightly below predicted values (89% of pred.). Conclusion Hemodynamic measurements revealed satisfying exercise adaptions and adequate prerequisites for intensive physical activities in selected patients even after HTX. However, compared to healthy athletes, SV was clearly limited to normal values (&lt;120 ml/beat). The deficit in CO occurs with moderate to heavy exercise levels could be partially compensated by increased avDO2 due to excellent peripheral function. Therefore, regular exercise training is crucial for this target group.