Kurt Wuyts

Exercise acutely reverses dysfunction of circulating angiogenic cells in chronic heart failure.

AIMS Recruitment of endothelial progenitor cells (EPCs) and enhanced activity of circulating angiogenic cells (CACs) might explain the benefits of exercise training in reversing endothelial dysfunction in chronic heart failure (CHF) patients. We studied baseline EPC numbers and CAC function and the effect of a single exercise bout. METHODS AND RESULTS Forty-one CHF patients (mild, n = 22; severe, n = 19) and 13 healthy subjects were included. Migratory activity of CACs was evaluated in vitro and circulating CD34+ and CD34+/KDR+ (EPC) cells were quantified by flow cytometry before and after cardiopulmonary exercise testing (CPET). Circulating stromal cell-derived factor-1alpha (SDF-1alpha) and vascular endothelial growth factor (VEGF) concentrations were measured. Both CAC migration as well as CD34+ cell numbers were significantly reduced in CHF, whereas CD34+/KDR+ cells were not different from controls. Endothelial dysfunction was related to impaired CAC migration (r = 0.318, P = 0.023). Cardiopulmonary exercise testing improved CAC migration in severe (+52%, P < 0.005) and mild CHF (+31%, P < 0.005), restoring it to levels similar to controls. Following CPET, SDF-1alpha increased in healthy controls and mild CHF (P < 0.005). Vascular endothelial growth factor, CD34+, and CD34+/KDR+ cell numbers remained unchanged. CONCLUSION The present findings reveal a potent stimulus of acute exercise to reverse CAC dysfunction in CHF patients with endothelial dysfunction.

Maintaining physical fitness of patients with chronic heart failure: a randomized controlled trial

Background We aimed to compare the effects of three different training advices, after 1 year, following a 6 months supervised cardiac rehabilitation period in patients with chronic heart failure (CHF). Methods Sixty-nine CHF patients were randomized, at the end of their rehabilitation period, either to usual care (UC) or to UC and controlled home training (HT), prolonged supervised training (ST) or preferred training (PT). Treadmill cardiopulmonary exercise testing was performed before rehabilitation, postrehabilitation and thereafter at 3-month intervals during the 1-year follow-up. submaximal exercise capacity [Oxygen consumption and workload at the respiratory compensation point (VO2RCP, WattRCP) and submaximal workload (SMW) efficiency (SMW/HR) at 70% of the initial maximal workload] was chosen as a primary endpoint, because health status in CHF patients depends largely on their ability to perform activities at a submaximal level. Results After 6 months of rehabilitation, the four groups (UC, HT, ST and PT) were comparable with regard to cardiac rehabilitation-derived benefit, both at the submaximal and maximal level. Although exercise capacity during follow-up declined in both UC and HT patients, ST and especially PT patients maintained and even improved VO2peak and VO2RCP. However, only PT patients managed to maintain or even increase submaximal (WattRCP and SMW/HR ratio) workload (P= 0.045 and <0.0001 for interaction, respectively). Ventilatory-derived prognostic markers during treadmill cardio pulmonary exercise testing evolved similarly in the four subgroups. Conclusion This study suggests that engagement in physical training of their own choice (PT), might be the optimal training modality for maintaining physical capacity in CHF patients.

The long-term effects of a randomized trial comparing aerobic interval versus continuous training in coronary artery disease patients: 1-year data from the SAINTEX-CAD study.

Background Aerobic interval training (AIT) and aerobic continuous training (ACT) both improve physical fitness (peak VO2) in coronary artery disease patients. However, little is known about the long-term effects of AIT and ACT on peak VO2 and exercise adherence. Design This study is a randomized clinical multicenter trial. Methods In total, 163 patients were assessed after 12 weeks of AIT or ACT and 12 months after their enrollment. Physical fitness and physical activity measures served as the primary outcomes, and peripheral endothelial function, cardiovascular risk factors and quality of life (QoL) served as the secondary outcomes. Results Twenty-six patients dropped out during the intervention; 11 were lost during the follow-up period. Dropouts (n = 37) consisted of more women (p = 0.001) compared to completers (n = 163). Physical fitness (VO2, heart rate and workload at peak and at thresholds) and physical activity (steps, active energy expenditure [kcal], physical activity duration [minutes]) were preserved at the 1-year follow-up (p-time > 0.05) after both AIT and ACT (p-interaction > 0.05). Forty percent of patients showed increased peak VO2, 52% showed increased active energy expenditure and 91.2% met the recommended levels of 150 minutes/week of moderate physical activity (p-group > 0.05). Further, peripheral endothelial function, QoL and cardiovascular risk factors, except systolic blood pressure (p-time < 0.05), remained stable (p-time > 0.05) after both AIT and ACT (p-interaction > 0.05). Conclusion The short-term improvements of center-based AIT and ACT on physical fitness, physical activity, peripheral endothelial function, cardiovascular risk factors and QoL are sustained after a 1-year follow-up period. The majority of patients (>90%) met the recommended physical activity levels of 150 minutes/week.

Impact of exercise testing mode on exercise parameters in patients with chronic heart failure

Aim: To verify the impact of testing mode on maximal, sub-maximal parameters and on cardiopulmonary exercise test (CPET) derived prognostic markers in patients with chronic heart failure (CHF). Method: 55 patients (age 60.3 years ±11.1) with CHF (ejection fraction 26 %±8) underwent a maximal CPET on a bicycle and on a treadmill, in a random order, within one week. Maximal, sub-maximal parameters and CPET derived prognostic markers were compared. Results: VO2peak and VO2peak corrected for lean body mass were significantly higher on treadmill compared to bicycle (+11%, p < 0.0001). This was also the case for the following sub-maximal parameters; heart rate, workload and VO2 at ventilatory anaerobic threshold and VO2 at the respiratory compensation point (RCP). In contrast, both VE/VCO2 slopes (start to RCP and start to end test) were similar. Time to ½ VO2peak was longer and circulatory power was higher on the treadmill compared to exercise testing on the bicycle. Conclusion: The results of the present study suggest that the mode of exercise testing significantly affects absolute values for VO2peak but does not greatly impact the prognostic utility of the VE/VCO2 slope in patients with moderate to severe CHF. Besides the consequences of these findings in terms of prognostication, testing mode should be taken into consideration when exercise prescription is based on VO2peak.

Comparison of three methods to identify the anaerobic threshold during maximal exercise testing in patients with chronic heart failure

ObjectiveExercise training efficiently improves peak oxygen uptake (V˙O2peak) in patients with chronic heart failure. To optimize training-derived benefit, higher exercise intensities are being explored. The correct identification of anaerobic threshold is important to allow safe and effective exercise prescription. DesignDuring 48 cardiopulmonary exercise tests obtained in patients with chronic heart failure (59.6 ± 11 yrs; left ventricular ejection fraction, 27.9% ± 9%), ventilatory gas analysis findings and lactate measurements were collected. Three technicians independently determined the respiratory compensation point (RCP), the heart rate turning point (HRTP) and the second lactate turning point (LTP2). Thereafter, exercise intensity (target heart rate and workload) was calculated and compared between the three methods applied. ResultsPatients had significantly reduced maximal exercise capacity (68% ± 21% of predicted V˙O2peak) and chronotropic incompetence (74% ± 7% of predicted peak heart rate). Heart rate, workload, and V˙O2 at HRTP and at RCP were not different, but at LTP2, these parameters were significantly (P < 0.0001) higher. Mean target heart rate and target workload calculated using the LTP2 were 5% and 12% higher compared with those calculated using HRTP and RCP, respectively. The calculation of target heart rate based on LTP2 was 5% and 10% higher in 12 of 48 (25%) and 6 of 48 (12.5%) patients, respectively, compared with the other two methods. ConclusionsIn patients with chronic heart failure, RCP and HRTP, determined during cardiopulmonary exercise tests, precede the occurrence of LTP2. Target heart rates and workloads used to prescribe tailored exercise training in patients with chronic heart failure based on LTP2 are significantly higher than those derived from HRTP and RCP.

The effect of aerobic interval training and continuous training on exercise capacity and its determinants

Objective We aimed to investigate (1) the effects of aerobic interval training (AIT) and aerobic continuous training (ACT) on (sub)maximal exercise measures and its determinants including endothelial function, muscle strength and cardiac autonomic function, and (2) the relationship between exercise capacity and these determinants. Methods Two-hundred coronary artery disease (CAD) patients (58.4 ± 9.1 years) were randomized to AIT or ACT for 12 weeks. All patients performed a cardiopulmonary exercise test and endothelial function measurements before and after the intervention; a subpopulation underwent muscle strength and heart rate variability (HRV) assessments. Results The VO2, heart rate and workload at peak and at first and second ventilatory threshold increased (P-time <0.001); the oxygen uptake efficiency slope (P-time <0.001) and half time of peak VO2 (P-time <0.001) improved. Endothelial function and heart rate recovery (HRR) at 1 and 2 min improved (P-time <0.001), while measures of muscle strength and HRV did not change. Both interventions were equally effective. Significant correlations were found between baseline peak VO2 and (1) quadriceps strength (r = 0.44; P < 0.001); (2) HRR at 2 min (r = 0.46; P < 0.001). Changes in peak VO2 correlated significantly with changes in (1) FMD (ρ = 0.17; P < 0.05); (2) quadriceps strength (r = 0.23; P < 0.05); (3) HRR at 2 min (ρ = 0.18; P < 0.05) and Total power of HRV (ρ = 0.41; P < 0.05). Conclusions This multicentre trial shows equal improvements in maximal and submaximal exercise capacity, endothelial function and HRR after AIT and ACT, while these training methods seem to be insufficient to improve muscle strength and HRV. Changes in peak VO2 were linked to changes in all underlying parameters.