Feasibility, Acceptability, and Clinical Effectiveness of a Technology-Enabled Cardiac Rehabilitation Platform (Physical Activity Toward Health-I): Randomized Controlled Trial.

BACKGROUND: Cardiac rehabilitation (CR) is highly effective as secondary prevention for cardiovascular diseases (CVDs). Uptake of CR remains suboptimal (30% of eligible patients), and long-term adherence to a physically active lifestyle is even lower. Innovative strategies are needed to counteract this phenomenon. OBJECTIVE: The Physical Activity Toward Health (PATHway) system was developed to provide a comprehensive, remotely monitored, home-based CR program for CVD patients. The PATHway-I study aimed to investigate its feasibility and clinical efficacy during phase III CR. METHODS: Participants were randomized on a 1:1 basis to the PATHway (PW) intervention group or usual care (UC) control group in a single-blind, multicenter, randomized controlled pilot trial. Outcomes were assessed at completion of phase II CR and 6-month follow-up. The primary outcome was physical activity (PA; Actigraph GT9X link). Secondary outcomes included measures of physical fitness, modifiable cardiovascular risk factors, endothelial function, intima-media thickness of the common carotid artery, and quality of life. System usability and patients' experiences were evaluated only in PW. A mixed-model analysis of variance with Bonferroni adjustment was used to analyze between-group effects over time. Missing values were handled by means of an intention-to-treat analysis. Statistical significance was set at a 2-sided alpha level of .05. Data are reported as mean (SD). RESULTS: A convenience sample of 120 CVD patients (mean 61.4 years, SD 13.5 years; 22 women) was included. The PATHway system was deployed in the homes of 60 participants. System use decreased over time and system usability was average with a score of 65.7 (SD 19.7; range 5-100). Moderate-to-vigorous intensity PA increased in PW (PW: 127 [SD 58] min to 141 [SD 69] min, UC: 146 [SD 66] min to 143 [SD 71] min; Pinteraction=.04; effect size of 0.42), while diastolic blood pressure (PW: 79 [SD 11] mmHg to 79 [SD 10] mmHg, UC: 78 [SD 9] mmHg to 83 [SD 10] mmHg; Pinteraction=.004; effect size of -0.49) and cardiovascular risk score (PW: 15.9% [SD 10.4%] to 15.5% [SD 10.5%], UC: 14.5 [SD 9.7%] to 15.7% [SD 10.9%]; Pinteraction=.004; effect size of -0.36) remained constant, but deteriorated in UC. CONCLUSIONS: This pilot study demonstrated the feasibility and acceptability of a technology-enabled, remotely monitored, home-based CR program. Although clinical effectiveness was demonstrated, several challenges were identified that could influence the adoption of PATHway. TRIAL REGISTRATION: ClinicalTrials.gov NCT02717806; https://clinicaltrials.gov/ct2/show/NCT02717806. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1136/bmjopen-2017-016781.

A Multi-Center Comparison of O2peak Trainability Between Interval Training and Moderate Intensity Continuous Training.

There is heterogeneity in the observed O2peak response to similar exercise training, and different exercise approaches produce variable degrees of exercise response (trainability). The aim of this study was to combine data from different laboratories to compare O2peak trainability between various volumes of interval training and Moderate Intensity Continuous Training (MICT). For interval training, volumes were classified by the duration of total interval time. High-volume High Intensity Interval Training (HIIT) included studies that had participants complete more than 15 min of high intensity efforts per session. Low-volume HIIT/Sprint Interval Training (SIT) included studies using less than 15 min of high intensity efforts per session. In total, 677 participants across 18 aerobic exercise training interventions from eight different universities in five countries were included in the analysis. Participants had completed 3 weeks or more of either high-volume HIIT (n = 299), low-volume HIIT/SIT (n = 116), or MICT (n = 262) and were predominately men (n = 495) with a mix of healthy, elderly and clinical populations. Each training intervention improved mean O2peak at the group level (P < 0.001). After adjusting for covariates, high-volume HIIT had a significantly greater (P < 0.05) absolute O2peak increase (0.29 L/min) compared to MICT (0.20 L/min) and low-volume HIIT/SIT (0.18 L/min). Adjusted relative O2peak increase was also significantly greater (P < 0.01) in high-volume HIIT (3.3 ml/kg/min) than MICT (2.4 ml/kg/min) and insignificantly greater (P = 0.09) than low-volume HIIT/SIT (2.5 mL/kg/min). Based on a high threshold for a likely response (technical error of measurement plus the minimal clinically important difference), high-volume HIIT had significantly more (P < 0.01) likely responders (31%) compared to low-volume HIIT/SIT (16%) and MICT (21%). Covariates such as age, sex, the individual study, population group, sessions per week, study duration and the average between pre and post O2peak explained only 17.3% of the variance in O2peak trainability. In conclusion, high-volume HIIT had more likely responders to improvements in O2peak compared to low-volume HIIT/SIT and MICT.

Predictors of response to exercise training in patients with coronary artery disease - a subanalysis of the SAINTEX-CAD study.

Exercise training improves peak oxygen uptake, an important predictor of mortality in coronary artery disease patients. The influence of clinical and disease characteristics on training response is not well established in coronary artery disease. Therefore, we aimed to evaluate whether baseline cardiovascular disease variables and training intensity can predict the maximal aerobic response to exercise training. The Study on Aerobic INTerval EXercise training in coronary artery disease patients (SAINTEX-CAD) previously showed that 12 weeks of aerobic interval training and continuous training equally improved peak oxygen uptake in coronary artery disease patients. We identified 24 exercise non-responders (change peak oxygen uptake <1 ml/kg/min) among 167 participants in SAINTEX-CAD. In a between-group comparison, exercise non-responders were older, their baseline peak oxygen uptake and oxygen uptake efficiency slope were higher, and exercise non-responders were more frequently included after elective percutaneous coronary intervention (all p < 0.05). In multiple logistic regression analysis, age (odds ratio = 1.11 (1.04-1.18), p = 0.001), history of elective percutaneous coronary intervention (odds ratio = 3.31 (1.12-9.76), p = 0.030) and higher baseline peak oxygen uptake (odds ratio = 1.16 (1.06-1.27), p = 0.001) were independent predictors of exercise non-response. In multiple linear regression analysis, age (ß = -0.605, p = 0.001), history of elective percutaneous coronary intervention (ß = -15.401, p = 0.010), training intensity (ß=0.447, p = 0.008), baseline physical activity (ß=0.014, p = 0.003) and oxygen uptake efficiency slope (ß = -0.014, p < 0.001) predicted percentage change in peak oxygen uptake and explained 41% of the variability in percentage change in peak oxygen uptake. To summarize, 14% of coronary artery disease patients were exercise non-responders. Higher baseline peak oxygen uptake and oxygen uptake efficiency slope, history of elective percutaneous coronary intervention, older age, lower training intensity and lower baseline physical activity were predictors of training non-response. Identification of patients with a large likelihood of non-response is a first step towards patient tailored exercise programmes.

C-reactive protein during and after myocardial infarction in relation to cardiac injury and left ventricular function at follow-up.

BACKGROUND: Acute myocardial infarction (MI) invokes a large inflammatory response, which contributes to myocardial repair. HYPOTHESIS: We investigated whether C-reactive protein (CRP) measured during MI vs at 1 month follow-up improves the prediction of left ventricular (LV) function. METHODS: We prospectively enrolled 131 consecutive patients with acute MI and without non-cardiovascular causes of inflammation. We correlated admission and peak levels of CRP during hospitalization and high-sensitivity (hs) CRP at 1 month follow-up with markers of cardiac injury. Clinical follow-up and echocardiography for LV function were performed at a mean of 17 months. RESULTS: Median CRP levels were 1.89 mg/L on admission with MI, peaked to 12.10 mg/L during hospitalization and dropped to 1.24 mg/L at 1 month. Although admission CRP levels only weakly correlated with ejection fraction in the acute phase of MI (coefficient -0.164, P = 0.094), peak CRP was significantly related to ejection fraction (coefficient -0.4, P < 0.001), hsTroponin T (0.389, P < 0.001), and white blood cell count (0.389, P < 0.001). hsCRP at 1 month was not related to the extent of acute cardiac injury. These findings were replicated in an independent cohort of 57 patients. Peak CRP predicted LV dysfunction at follow-up (OR 11.0, 3.1-39.5 per log CRP, P < 0.001), persisting after adjustment for infarct size (OR 5.1, 1.1-23.6, P = 0.037), while hsCRP at 1 month was unrelated to LV function at follow-up. CONCLUSIONS: hsCRP 1 month post-MI does not relate to acute cardiac injury or LV function at follow-up, but we confirm that peak CRP is an independent predictor of LV dysfunction at follow-up.

Impact of aerobic interval training and continuous training on left ventricular geometry and function: a SAINTEX-CAD substudy.

BACKGROUND: Increase of exercise capacity (peak VO2) after cardiac rehabilitation improves outcome in patients with coronary artery disease (CAD). Systolic and diastolic function have been associated with peak VO2, but their role towards improvement of exercise capacity remains unclear. It is unknown which exercise intensity has the most beneficial impact on left ventricular (LV) geometry and function in CAD patients without heart failure. METHODS: 200 stable CAD patients without heart failure were randomized to 3months of aerobic interval training (AIT) or aerobic continuous training (ACT). Cardiopulmonary exercise test and transthoracic echocardiography were scheduled before and after 3months of training. RESULTS: At baseline, a higher peak VO2 correlated with lower LV posterior wall thickness (p=0.002), higher LV ejection fraction (p=0.008), better LV global longitudinal strain (p=0.043) and lower E/e' (0=0.001). After multivariate stepwise regression analysis only E/é remained an independent predictor of peak VO2 (p=0.042). Improvement of peak VO2 after 3months of training correlated with reverse remodeling of the interventricular septum (p=0.005), enlargement of LV diastolic volume (p=0.007) and increase of LV stroke volume (p=0.018) but not with other indices of systolic or diastolic function. Significant reduction of the interventricular septum thickness after cardiac rehabilitation was observed (p=0.012), with a trend towards more reverse remodeling after ACT compared to AIT (p=0.054). In contrast, there were no changes in other parameters of LV geometry, diastolic or systolic function. CONCLUSION: Systolic and diastolic function are determinants of baseline exercise capacity in CAD patients without heart failure, but do not seem to mediate improvement of peak VO2 after either AIT or ACT.

Aerobic Interval vs. Continuous Training in Patients with Coronary Artery Disease or Heart Failure: An Updated Systematic Review and Meta-Analysis with a Focus on Secondary Outcomes.

BACKGROUND: In a previous meta-analysis including nine trials comparing aerobic interval training with aerobic continuous training in patients with coronary artery disease, we found a significant difference in peak oxygen uptake favoring aerobic interval training. OBJECTIVE: The objective of this study was to (1) update the original meta-analysis focussing on peak oxygen uptake and (2) evaluate the effect on secondary outcomes. METHODS: We conducted a systematic review with a meta-analysis by searching PubMed and SPORTDiscus databases up to March 2017. We included randomized trials comparing aerobic interval training and aerobic continuous training in patients with coronary artery disease or chronic heart failure. The primary outcome was change in peak oxygen uptake. Secondary outcomes included cardiorespiratory parameters, cardiovascular risk factors, cardiac and vascular function, and quality of life. RESULTS: Twenty-four papers were identified (n = 1080; mean age 60.7 ± 10.7 years). Aerobic interval training resulted in a higher increase in peak oxygen uptake compared with aerobic continuous training in all patients (1.40 mL/kg/min; p < 0.001), and in the subgroups of patients with coronary artery disease (1.25 mL/kg/min; p = 0.001) and patients with chronic heart failure with reduced ejection fraction (1.46 mL/kg/min; p = 0.03). Moreover, a larger increase of the first ventilatory threshold and peak heart rate was observed after aerobic interval training in all patients. Other cardiorespiratory parameters, cardiovascular risk factors, and quality of life were equally affected. CONCLUSION: This meta-analysis adds further evidence to the clinically significant larger increase in peak oxygen uptake following aerobic interval training vs. aerobic continuous training in patients with coronary artery disease and chronic heart failure. More well-designed randomized controlled trials are needed to establish the safety of aerobic interval training and the sustainability of the training response over longer periods.

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.

Predictive value of Type D personality for impaired endothelial function in patients with coronary artery disease.

BACKGROUND: Type D personality (high negative affectivity and social inhibition) is associated with cardiovascular events and coronary plaque severity. Whether Type D is also related to functional vasomotion abnormalities is unknown. We examined concurrent and predictive associations of Type D with endothelial dysfunction in patients with coronary artery disease (CAD). METHODS: At baseline, 180 CAD patients (90% men; M = 58.0 years) completed Type D (DS14) and depression scales, and entered a 12-week exercise program. Flow-mediated dilation (FMD) of the brachial artery and circulating CD34+/KDR+/CD45+dim endothelial progenitor cells (EPCs) were assessed at baseline, 3 months, and 12 months. Logistic regression and linear mixed models were used to analyze endothelial function. RESULTS: Type D personality was associated with decreased FMD across baseline, 3 months, and 12 months (mixed model analysis, p = 0.04), after adjustment for clinical characteristics, exercise training and depression. There was no significant association between Type D and decreased EPCs (p = 0.07). Age and smoking were other significant correlates of FMD and EPCs. Using a FMD <5.5% cut-off, Type D patients more often had endothelial dysfunction at baseline (24/37 = 65%) than non-Type Ds (63/143 = 44%); OR = 3.03, 95% CI 1.04-8.80. This significant Type D effect was confirmed in prospective analyses of endothelial dysfunction at 12 months (OR = 3.43, 95% CI 1.01-11.64), and in subgroup analyses of male patients. CONCLUSIONS: Type D personality was associated with impaired endothelial function in men with CAD. This association was robust across time, independent from depressive symptoms, and supports the notion that Type D has an adverse effect on cardiovascular health in patients with CAD.

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.

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.

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.

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 ((Equation is included in full-text article.)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 (Equation is included in full-text article.)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 (Equation is included in full-text article.)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 (Equation is included in full-text article.)O2 (ICC, 0.97; 95% CI, 0.95-0.98). The ventilation/carbon dioxide production ((Equation is included in full-text article.)E/(Equation is included in full-text article.)CO2) slope showed very good test-retest reliability (ICC, 0.87; 95% CI, 0.80-0.91) and the (Equation is included in full-text article.)O2/work rate slope showed good reliability (ICC, 0.76; 95% CI, 0.64-0.85). CONCLUSIONS: Both peak (Equation is included in full-text article.)O2 and OUES show excellent test-retest reliability. Accordingly, in the case of no or unreliable peak (Equation is included in full-text article.)O2 data, we suggest using OUES to evaluate cardiorespiratory fitness in patients with CAD.

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.

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.

Aerobic interval training vs. moderate continuous training in coronary artery disease patients: a systematic review and meta-analysis.

BACKGROUND: Exercise training improves exercise capacity (peakVO2), which is closely related to long-term survival in cardiac patients. However, it remains unclear which type and intensity of exercise is most effective for improving exercise tolerance and body weight. Individual studies suggest that aerobic interval training (AIT) might increase peakVO2 more in this population. OBJECTIVE: We conducted a meta-analysis to summarize the effects of AIT compared with moderate continuous training (MCT) on peakVO2, submaximal exercise capacity, and body weight in patients with coronary artery disease (CAD) with preserved and/or reduced left ventricular ejection fraction (LVEF). DATA SOURCES AND STUDY SELECTION: A systematic search was conducted and we included randomized trials comparing AIT and MCT in CAD patients lasting at least 4 weeks, reporting peakVO2 results, and published in a peer-reviewed journal up to May 2013. The primary outcome measure was peakVO2. Secondary outcomes were submaximal exercise capacity parameters and body weight. SYNTHESIS METHODS: Random- and fixed-effects models were used and data were reported as weighted means and 95% confidence intervals (CIs). RESULTS: Nine study groups were included, involving 206 patients (100 AIT, 106 MCT). Overall, AIT resulted in a significantly larger increase in peakVO2 [+1.60 mL/kg/min (95% CI 0.18-3.02; p = 0.03)] compared with MCT. MCT seemed to be more effective in reducing body weight (-0.78 kg; 95% CI -0.01 to 1.58; p = 0.05). LIMITATIONS: The small number of studies might have affected the power to reach significance for the secondary outcomes. CONCLUSION: In CAD patients with preserved and/or reduced LVEF, AIT is superior to MCT for improving peakVO2, while MCT seems to be more effective in reducing body weight. However, large, well-designed, randomized controlled trials are warranted to confirm these findings.

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 effect of exercise on the cardiovascular risk factors constituting the metabolic syndrome: a meta-analysis of controlled trials.

BACKGROUND: Numerous meta-analyses have investigated the effect of exercise in different populations and for single cardiovascular risk factors, but none have specifically focused on the metabolic syndrome (MetS) patients and the concomitant effect of exercise on all associated cardiovascular risk factors. OBJECTIVE: The aim of this article was to perform a systematic review with a meta-analysis of randomized and clinical controlled trials (RCTs, CTs) investigating the effect of exercise on cardiovascular risk factors in patients with the MetS. METHODS: RCTs and CTs ≥4 weeks investigating the effect of exercise in healthy adults with the MetS and published in a peer-reviewed journal up to November 2011 were included. Primary outcome measures were changes in waist circumference (WC), systolic and diastolic blood pressure, high-density lipoprotein cholesterol (HDL-C), triglycerides and fasting plasma glucose. Peak oxygen uptake ([Formula: see text]) was a secondary outcome. Random and fixed-effect models were used for analyses and data are reported as means and 95% confidence intervals (CIs). RESULTS: Seven trials were included, involving nine study groups and 206 participants (128 in exercise group and 78 in control group). Significant mean reductions in WC -3.4 (95% CI -4.9, -1.8) cm, blood pressure -7.1 (95% CI -9.03, -5.2)/-5.2 (95% CI -6.2, -4.1) mmHg and a significant mean increase in HDL-C +0.06 (95% CI +0.03, +0.09) mmol/L were observed after dynamic endurance training. Mean plasma glucose levels -0.31 (95% CI -0.64, 0.01; p = 0.06) mmol/L and triglycerides -0.05 (95% CI -0.20, 0.09; p = 0.47) mmol/L remained statistically unaltered. In addition, a significant mean improvement in [Formula: see text] of +5.9 (95% CI +3.03, +8.7) mL/kg/min or 19.3% was found. CONCLUSIONS: Our results suggest that dynamic endurance training has a favourable effect on most of the cardiovascular risk factors associated with the MetS. However, in the search for training programmes that optimally improve total cardiovascular risk, further research is warranted, including studies on the effects of resistance training and combined resistance and endurance training.

Cardiac MRI: 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.