Nele Pattyn

Aerobic interval training and continuous training equally improve aerobic exercise capacity in patients with coronary artery disease: the SAINTEX-CAD study.

BACKGROUND Exercise-based cardiac rehabilitation increases peak oxygen uptake (peak VO₂), which is an important predictor of mortality in cardiac patients. However, it remains unclear which exercise characteristics are most effective for improving peak VO₂ in coronary artery disease (CAD) patients. Proof of concept papers comparing Aerobic Interval Training (AIT) and Moderate Continuous Training (MCT) were conducted in small sample sizes and findings were inconsistent and heterogeneous. Therefore, we aimed to compare the effects of AIT and Aerobic Continuous Training (ACT) on peak VO₂, peripheral endothelial function, cardiovascular risk factors, quality of life and safety, in a large multicentre study. METHODS Two-hundred CAD patients (LVEF >40%, 90% men, mean age 58.4 ± 9.1 years) were randomized to a supervised 12-week cardiac rehabilitation programme of three weekly sessions of either AIT (90-95% of peak heart rate (HR)) or ACT (70-75% of peak HR) on a bicycle. Primary outcome was peak VO₂; secondary outcomes were peripheral endothelial function, cardiovascular risk factors, quality of life and safety. RESULTS Peak VO₂ (ml/kg/min) increased significantly in both groups (AIT 22.7 ± 17.6% versus ACT 20.3 ± 15.3%; p-time<0.001). In addition, flow-mediated dilation (AIT+34.1% (range -69.8 to 646%) versus ACT+7.14% (range -66.7 to 503%); p-time<0.001) quality of life and some other cardiovascular risk factors including resting diastolic blood pressure and HDL-C improved significantly after training. Improvements were equal for both training interventions. CONCLUSIONS Contrary to earlier smaller trials, we observed similar improvements in exercise capacity and peripheral endothelial function following AIT and ACT in a large population of CAD patients.

Rationale and design of a randomized trial on the effectiveness of aerobic interval training in patients with coronary artery disease: The SAINTEX-CAD study

BACKGROUND Exercise-based cardiac rehabilitation is considered an important adjunct treatment and secondary prevention measure in patients with coronary artery disease (CAD). However, the issues of training modality and exercise intensity for CAD patients remain controversial. OBJECTIVE Main aim of the present study is to test the hypothesis that aerobic interval training (AIT) yields a larger gain in peak aerobic capacity (peakVO2) compared to a similar training programme of moderate continuous training (MCT) in CAD patients. STUDY DESIGN In this multicentre study stable CAD patients with left ventricular ejection fraction>40% will be randomized after recent myocardial infarction or revascularization (PCI or CABG) to a supervised 12-week programme of three weekly sessions of either AIT (85-90% of peak oxygen uptake [peakVO2], 90-95% of peak heart rate) or MCT (60-70% of peakVO2, 65-75% of peak heart rate). The primary endpoint of the study is the change of peakVO2 after 12 weeks training. Secondary endpoints include safety, changes in peripheral endothelial vascular function, the evolution of traditional cardiovascular risk factors, quality of life and the number and function of circulating endothelial progenitor cells as well as endothelial microparticles. Possible differences in terms of long-term adherence to prescribed exercise regimens will be assessed by regular physical activity questionnaires, accelerometry and reassessment of peakVO2 12 months after randomization. A total number of 200 patients will be randomized in a 1:1 manner (significance level of 0.05 and statistical power of 0.90). Enrolment started December 2010; last enrolment is expected for February 2013.

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.

Technical proficiency among table tennis players with and without intellectual disabilities

A relatively small body of research addresses the effect of intellectual impairment on proficiency in sport. The aim in the present study was to determine whether the technical proficiency of table tennis players (TTP) with and without intellectual disability (ID), matched for years of training experience, are different. The sample consisted of 71 elite TTP with ID (41 males, age=27±8 years, IQ=61±9; and 30 females, age=28±8 years, IQ=57±10; M±SD) and a comparison group of 17 players (12 males; age=24±12 years; and 5 females, age=20±9 years) without ID. All were assessed using a test-battery that included 10 sets of five basic and five advanced technical skills. Statistical analysis (ANOVA) revealed no gender differences in proficiency. The total score on technical proficiency for ID players (63.7%±12.5) ranged between 53% (advanced strokes) and 76% (basic strokes). Table tennis players without ID scored significantly better: 87.6%±6.2 (range: 80-94%). The significance of these differences in technical proficiency held even when delimiting the comparison to the top 8 players (age=25.9±7.0, IQ=61.8±9.8) with ID and counter-parts without ID who competed at regional levels in their country. The top eight players scored 73.1%±7.4 (range: 65-81.6%). These results suggest that impaired cognitive functioning may have a direct bearing on technical proficiency in sport.

Cardiac Magnetic Resonance Imaging: A New Gold Standard for Ventricular Volume Quantification During High-Intensity Exercise

Background— Accurate measures are critical when attempting to distinguish normal from pathological changes in cardiac function during exercise, yet imaging modalities have seldom been assessed against invasive exercise standards. We sought to validate a novel method of biventricular volume quantification by cardiac MRI (CMR) during maximal exercise. Methods and Results— CMR was performed on 34 subjects during exercise and free-breathing with the use of an ungated real-time (RT-ungated) CMR sequence. ECG and respiratory movements were retrospectively synchronized, enabling compensation for cardiac cycle and respiratory phase. Feasibility of RT-ungated imaging was compared with standard exercise CMR imaging with ECG gating (gated); accuracy of RT-ungated CMR was assessed against an invasive standard (direct Fick); and reproducibility was determined after a second bout of maximal exercise. Ventricular volumes were analyzed more frequently during high-intensity exercise with RT-ungated compared with gated CMR (100% versus 47%; P<0.0001) and with better interobserver variability for RT-ungated (coefficient of variation=1.9% and 2.0% for left and right ventricular stroke volumes, respectively) than gated (coefficient of variation=15.2% and 13.6%; P<0.01). Cardiac output determined by RT-ungated CMR proved accurate against the direct Fick method with excellent agreement (intraclass correlation coefficient, R=0.96), which was highly reproducible during a second bout of maximal exercise (R=0.98). Conclusions— When RT-ungated CMR is combined with post hoc analysis incorporating compensation for respiratory motion, highly reproducible and accurate biventricular volumes can be measured during maximal exercise.Background— Accurate measures are critical when attempting to distinguish normal from pathological changes in cardiac function during exercise, yet imaging modalities have seldom been assessed against invasive exercise standards. We sought to validate a novel method of biventricular volume quantification by cardiac MRI (CMR) during maximal exercise. Methods and Results— CMR was performed on 34 subjects during exercise and free-breathing with the use of an ungated real-time (RT-ungated) CMR sequence. ECG and respiratory movements were retrospectively synchronized, enabling compensation for cardiac cycle and respiratory phase. Feasibility of RT-ungated imaging was compared with standard exercise CMR imaging with ECG gating (gated); accuracy of RT-ungated CMR was assessed against an invasive standard (direct Fick); and reproducibility was determined after a second bout of maximal exercise. Ventricular volumes were analyzed more frequently during high-intensity exercise with RT-ungated compared with gated CMR (100% versus 47%; P <0.0001) and with better interobserver variability for RT-ungated (coefficient of variation=1.9% and 2.0% for left and right ventricular stroke volumes, respectively) than gated (coefficient of variation=15.2% and 13.6%; P <0.01). Cardiac output determined by RT-ungated CMR proved accurate against the direct Fick method with excellent agreement (intraclass correlation coefficient, R =0.96), which was highly reproducible during a second bout of maximal exercise ( R =0.98). Conclusions— When RT-ungated CMR is combined with post hoc analysis incorporating compensation for respiratory motion, highly reproducible and accurate biventricular volumes can be measured during maximal exercise.

Effects of aerobic interval training and continuous training on cellular markers of endothelial integrity in coronary artery disease: a SAINTEX-CAD substudy

In this large multicenter trial, we aimed to assess the effect of aerobic exercise training in stable coronary artery disease (CAD) patients on cellular markers of endothelial integrity and to examine their relation with improvement of endothelial function. Two-hundred CAD patients (left ventricular ejection fraction > 40%, 90% male, mean age 58.4 ± 9.1 yr) were randomized on a 1:1 base to a supervised 12-wk rehabilitation program of either aerobic interval training or aerobic continuous training on a bicycle. At baseline and after 12 wk, numbers of circulating CD34(+)/KDR(+)/CD45dim endothelial progenitor cells (EPCs), CD31(+)/CD3(+)/CXCR4(+) angiogenic T cells, and CD31(+)/CD42b(-) endothelial microparticles (EMPs) were analyzed by flow cytometry. Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery. After 12 wk of aerobic interval training or aerobic continuous training, numbers of circulating EPCs, angiogenic T cells, and EMPs were comparable with baseline levels. Whereas improvement in peak oxygen consumption was correlated to improvement in FMD (Pearson r = 0.17, P = 0.035), a direct correlation of baseline or posttraining EPCs, angiogenic T cells, and EMP levels with FMD was absent. Baseline EMPs related inversely to the magnitude of the increases in peak oxygen consumption (Spearman rho = -0.245, P = 0.027) and FMD (Spearman rho = -0.374, P = 0.001) following exercise training. In conclusion, endothelial function improvement in response to exercise training in patients with CAD did not relate to altered levels of EPCs and angiogenic T cells and/or a diminished shedding of EMPs into the circulation. EMP flow cytometry may be predictive of the increase in aerobic capacity and endothelial function.

Exercise cardiac magnetic resonance to differentiate athlete’s heart from structural heart disease

Aims The distinction between left ventricular (LV) dilation with mildly reduced LV ejection fraction (EF) in response to regular endurance exercise training and an early cardiomyopathy is a frequently encountered and difficult clinical conundrum. We hypothesized that exercise rather than resting measures would provide better discrimination between physiological and pathological LV remodelling and that preserved exercise capacity does not exclude significant LV damage. Methods and results We prospectively included 19 subjects with LVEF between 40 and 52%, comprising 10 ostensibly healthy endurance athletes (EA-healthy) and nine patients with dilated cardiomyopathy (DCM). In addition, we recruited five EAs with a region of subepicardial LV. Receiver operating characteristic fibrosis (EA-fibrosis). Cardiac magnetic resonance (CMR) imaging was performed at rest and during supine bicycle exercise. Invasive afterload measures were obtained to enable calculations of biventricular function relative to load (an estimate of contractility). In DCM and EA-fibrosis subjects there was diminished augmentation of LVEF (5 ± 6% vs. 4 ± 3% vs. 14 ± 3%; P = 0.001) and contractility [LV end-systolic pressure-volume ratio, LVESPVR; 1.4 (1.3-1.6) vs. 1.5 (1.3-1.6) vs. 1.8 (1.7-2.7); P < 0.001] during exercise relative to EA-healthy. Receiver-operator characteristic curves demonstrated that a cut-off value of 11.2% for ΔLVEF differentiated DCM and EA-fibrosis patients from EA-healthy [area under the curve (AUC) = 0.92, P < 0.001], whereas resting LVEF and VO2max were not predictive. The AUC value for LVESPVR ratio was similar to that of ΔLVEF. Conclusions Functional cardiac evaluation during exercise is a promising tool in differentiating healthy athletes with borderline LVEF from those with an underlying cardiomyopathy. Excellent exercise capacity does not exclude significant LV damage.

Are aerobic interval training and continuous training isocaloric in coronary artery disease patients

Background Aerobic interval training (IT) seems to be superior to continuous training (CT) in improving exercise capacity (peak oxygen uptake (VO2)) in coronary artery disease (CAD) patients in some, but not in all studies. Based on theoretical calculations, these comparative studies stated that the energy expenditure (EE) of both programmes is similar. To date, the caloricity of both programmes has never been objectively measured. Therefore, our aim was to objectively measure the EE of the IT and CT programmes described in the protocol of the SAINTEX-CAD study (based on Wisloff et al.; ITw and CTw), and the actually performed training intensities in the SAINTEX-CAD study by Conraads et al. (ITc and CTc). Methods Following a two-week run-in period with three IT and three CT training sessions, 18 male CAD patients (mean age 62.4 ± 6.1 years) performed four training sessions in random order on the cycle ergometer: an ITw, CTw, ITc and CTc test session. The EE was assessed by indirect calorimetry using gas exchange measurements obtained with the Oxycon mobile. Results We found a higher EE for CTc compared to ITc (352 ± 90.8 kcal versus 269 ± 70.7 kcal; p = 0.026), while CTw and ITw seemed to be isocaloric (317 ± 85.2 kcal versus 273 ± 65.3 kcal; p = 0.42). Higher lactate levels were reached after IT sessions (ITw 5.42 ± 1.42 mmol/l, ITc 5.05 ± 1.38 mmol/l) compared to CT sessions (CTw 2.45 ± 1.04 mmol/l, CTc 3.41 ± 1.44 mmol/l) (p < 0.01). Lactate levels increased above baseline levels (1.91 ± 0.34 mmol/l) except for the CTw session. Conclusion CTc expended significantly more energy compared to ITc, showing that the programmes used in the SAINTEX-CAD study were not isocaloric. In contrast, isocaloricity was met for CTw and ITw.

High intensity interval training in coronary artery disease patients, is it worth the effort?:

Coronary artery disease (CAD) is the leading cause of death in Europe and worldwide. Based on a large body of evidence that shows that participation in cardiac rehabilitation (CR) reduces CAD mortality and morbidity and improves exercise capacity and quality of life, referral to exercise-based CR is now a class I recommendation for CAD patients. Nevertheless, the effectiveness of CR depends largely on the intensity, duration, frequency and type (FITT) of exercise; although the optimal exercise prescription remains under debate. For decades, there has been a historical preference in the guidelines to recommend moderate intensity continuous training (MCT) for patients with CAD. Yet, approximately 15 years ago, high(er) intensity interval training (HIIT) alternating high intensity (80–120% of peak oxygen consumption (VO2)) bouts with periods of active or passive recovery was introduced in CR by the Norwegian group of Wisloff et al., showing superior clinical improvements in patients with CAD and chronic heart failure (CHF). Among others, these proof of concept studies reported a two to three times larger increase in exercise capacity after HIIT compared to MCT. Since then, a growing number of trials has compared the effectiveness of HIIT and MCT in CAD patients and other chronic disease populations. Although the results of these small individual studies were contradictory and inconclusive, pooling their data by means of meta-analytic techniques unambiguously showed higher clinically relevant improvements in peak VO2 in CAD patients after HIIT ranging from 1.53 to 1.78ml/kg/min. Since the publication of the largest meta-analysis, involving nine studies and 206 CAD patients, the multicentre study SAINTEX-CAD was published almost doubling the number of CAD patients included so far. In the present issue of this journal, a systematic review and meta-analysis was performed by GomesNeto et al. to provide an updated analysis of data from randomised controlled trials comparing HIIT to MCT in patients with CAD. The primary outcomes were exercise capacity and quality of life. The overall results of this study, involving data of 11 trials and 594 patients, are in line with previous meta-analyses and confirm a significantly larger effect size for exercise capacity (þ1.25ml/min/kg) in favour of HIIT. However, the novelty of this study is to be found in a subgroup analysis based on whether the exercise protocols were or were not isocaloric. When Gomes-Neto et al. pooled the data of four trials that matched their exercise interventions for energy expenditure (EE), they found similar improvements in exercise capacity (þ0.36ml/kg/min (–0.14 to þ0.85) P1⁄4 0.16) following HIIT and MCT. These results suggest that not the intensity nor the modality but the total EE of the exercise programmes determines the improvement in exercise capacity after training. This concords with a recent meta-analysis by Kraal et al., who showed that session duration, programme length and training intensity were all related to the improvement in exercise capacity, but found no independent effect of any of these training characteristics after correction for total EE in patients with CAD. As such, one could conclude that HIIT offers a time-efficient alternative for MCT as it requires less time (approximately 30 minutes/week) to be spent exercising while providing similar health benefits compared to MCT. As a result, HIIT can overcome one of the most frequently cited barriers to physical activity, which is lack of time. Nevertheless, these results also imply that one can achieve the same gains with less strain: i.e. if we spend enough minutes exercising at moderate intensity we obtain the same improvements, which, from an adherence perspective, might be as important as saving 30 minutes per week.

Test-Retest Reliability of Maximal and Submaximal Gas Exchange Variables in Patients With Coronary Artery Disease.

PURPOSE: Gas exchange variables derived from cardiopulmonary exercise tests (CPETs) need to be reliable for evaluating interventions and clinical decision making. Whereas peak oxygen uptake ( O2) has shown to be a highly reliable parameter in patients with coronary artery disease (CAD), little is known about the reproducibility of these parameters in patients with CAD. Therefore, the purpose of this study was to confirm the reliability of peak O2 and to investigate the reliability of submaximal CPET variables in patients with CAD. METHODS: Eighty-five patients with CAD (57.6 ± 8.5 years; 79 males) performed 2 CPETs within 10 days before starting a rehabilitation program. Reliability of peak and submaximal exercise variables was assessed by using intraclass correlation coefficients (ICC), coefficients of variation, Pearson correlation coefficients, paired t tests, and Bland-Altman plots. RESULTS: Maximal and submaximal exercise parameters showed adequate reliability. Overall, there was a good correlation across both testing occasions (r = 0.63-0.95; P < .05 for all). Peak O2 (ICC, 0.95; 95% CI, 0.92-0.97) demonstrated excellent reliability. Of the submaximal exercise variables, oxygen uptake efficiency slope (OUES) was as reliable as peak O2 (ICC, 0.97; 95% CI, 0.95-0.98). The ventilation/carbon dioxide production ( E/ CO2) slope showed very good test-retest reliability (ICC, 0.87; 95% CI, 0.80-0.91) and the O2/work rate slope showed good reliability (ICC, 0.76; 95% CI, 0.64-0.85). CONCLUSIONS: Both peak O2 and OUES show excellent test-retest reliability. Accordingly, in the case of no or unreliable peak O2 data, we suggest using OUES to evaluate cardiorespiratory fitness in patients with CAD.