Failure to improve cardiopulmonary fitness in cardiac rehabilitation

A standardized approach to evaluate effectiveness of aerobic exercise training interventions in cardiovascular disease at the individual level

BACKGROUND

Reliable change indices can determine pre-post intervention changes at an individual level that are greater than chance or practice effect. We applied previously developed minimal meaningful change (MMCRCI) scores for oxygen uptake (V̇O2) values associated with estimated lactate threshold (θLT), respiratory compensation point (RCP), and peak oxygen uptake (V̇O2peak) to evaluate the effectiveness of exercise training in cardiovascular disease patients.

METHODS

303 patients (65 ± 11 yrs.; 27% female) that completed a symptom-limited cardiopulmonary exercise test (CPET) before and after 6-months of guideline-recommended exercise training were assessed to determine absolute and relative V̇O2 at θLT, RCP, and V̇O2peak. Using MMCRCI ∆V̇O2 scores of ±3.9 mL·kg-1·min-1, ±4.0 mL·kg-1·min-1, and ± 3.6 mL·kg-1·min-1 for θLT, RCP, and V̇O2peak, respectively, patients were classified as "positive" (ΔθLT, ΔRCP, and/or ΔV̇O2peak ≥ +MMCRCI), "non-" (between ±MMCRCI), or "negative" responders (≤ -MMCRCI).

RESULTS

Mean RCP (n = 86) and V̇O2peak (n = 303) increased (p < 0.05) from 19.4 ± 3.6 mL·kg-1·min-1 and 18.0 ± 6.3 mL·kg-1·min-1 to 20.1 ± 3.8 mL·kg-1·min-1 and 19.2 ± 7.0 mL·kg-1·min-1 at exit, respectively, whereas θLT (n = 140) did not change (15.5 ± 3.4 mL·kg-1·min-1 versus 15.7 ± 3.8 mL·kg-1·min-1, p = 0.324). For changes in θLT, 6% were classified as "positive" responders, 90% as "non-responders", and 4% as "negative" responders. For RCP, 10% exhibited "positive" changes, 87% were "non-responders", and 2% were "negative" responders. For ΔV̇O2peak, 57 patients (19%) were classified as "positive" responders, 229 (76%) as "non-responders", and 17 (6%) as "negative" responders.

CONCLUSION

Most patients that completed the exercise training program did not achieve reliable improvements greater than that of chance or practice at an individual level in θLT, RCP and V̇O2peak.

Effect of Cardiac Rehabilitation on Cardiorespiratory Fitness in Patients With Acute Myocardial Infarction: Role of Diabetes Mellitus and Glycated Hemoglobin Level

PURPOSE

Following acute myocardial infarction (AMI), patients with diabetes mellitus (DM) have a poorer prognosis than those without DM. This study aimed to investigate the benefit of cardiac rehabilitation on cardiorespiratory fitness in patients with AMI, examining whether this effect varied depending on DM and glycated hemoglobin (HbA1c) levels.

METHODS

Data were collected from the medical records of 324 patients diagnosed with AMI who were subsequently referred to participate in a supervised exercise-based cardiac rehabilitation program. Cardiorespiratory fitness was assessed using cardiopulmonary exercise testing before and at 3 and 6 mo after the start of cardiac rehabilitation. Linear mixed models were used to evaluate changes in cardiorespiratory fitness between patients with and without DM during the follow-up period.

RESULTS

In total, 106 patients (33%) had DM. Both patients with and without DM showed a significant improvement in cardiorespiratory fitness from baseline to the 6-mo follow-up. However, the improvement was significantly lower in patients with DM than in those without DM (1.9 ± 1.5 vs. 3.7 ± 3.2 mL/kg/min, P < .001). Among patients with DM, those with HbA1c levels < 7% showed a greater improvement in cardiorespiratory fitness than those with HbA1c ≥ 7% (2.7 ± 1.5 vs. 1.1 ± 1.8 mL/kg/min, P < .001) during the follow-up period.

CONCLUSIONS

Improvements in cardiorespiratory fitness following cardiac rehabilitation were significantly lower in patients with AMI and DM. The response to cardiac rehabilitation in patients is influenced by HbA1c levels. These findings suggest potential implications for individualizing cardiac rehabilitation programming and ensuring optimal glycemic control in patients with AMI and DM.

Heavy-, Severe-, and Extreme-, but Not Moderate-Intensity Exercise Increase V̇o 2max and Thresholds after 6 wk of Training

INTRODUCTION

This study assessed the effect of individualized, domain-based exercise intensity prescription on changes in maximal oxygen uptake (V̇O 2max ) and submaximal thresholds.

METHODS

Eighty-four young healthy participants (42 females, 42 males) were randomly assigned to six age, sex, and V̇O 2max -matched groups (14 participants each). Groups performed continuous cycling in the 1) moderate (MOD), 2) lower heavy (HVY1), and 3) upper heavy-intensity (HVY2) domain; interval cycling in the form of 4) high-intensity interval training (HIIT) in the severe-intensity domain, or 5) sprint-interval training (SIT) in the extreme-intensity domain; or no exercise for 6) control (CON). All training groups, except SIT, were work-matched. Training participants completed three sessions per week for 6 wk with physiological evaluations performed at PRE, MID, and POST intervention.

RESULTS

Compared with the change in V̇O 2max (∆V̇O 2max ) in CON (0.1 ± 1.2 mL·kg -1 ·min -1 ), all training groups, except MOD (1.8 ± 2.7 mL·kg -1 ·min -1 ), demonstrated a significant increase ( P < 0.05). HIIT produced the highest increase (6.2 ± 2.8 mL·kg -1 ·min -1 ) followed by HVY2 (5.4 ± 2.3 mL·kg -1 ·min -1 ), SIT (4.7 ± 2.3 mL·kg -1 ·min -1 ), and HVY1 (3.3 ± 2.4 mL·kg -1 ·min -1 ), respectively. The ΔPO at the estimated lactate threshold ( θLT ) was similar across HVY1, HVY2, HIIT, and SIT, which were all greater than CON ( P < 0.05). The ΔV̇O 2 and ΔPO at θLT for MOD was not different from CON ( P > 0.05). HIIT produced the highest ΔPO at maximal metabolic steady state, which was greater than CON, MOD, and SIT ( P < 0.05).

CONCLUSIONS

This study demonstrated that i) exercise intensity is a key component determining changes in V̇O 2max and submaximal thresholds and ii) exercise intensity domain-based prescription allows for a homogenous metabolic stimulus across individuals.

Neurofilament Light Chain as a Biomarker of Global Cognition in Individuals With Possible Vascular Mild Cognitive Impairment

BACKGROUND

Neurofilament Light Chain (NfL) is a biomarker of axonal injury elevated in mild cognitive impairment (MCI) and Alzheimer's disease dementia. Blood NfL also inversely correlates with cognitive performance in those conditions. However, few studies have assessed NfL as a biomarker of global cognition in individuals demonstrating mild cognitive deficits who are at risk for vascular-related cognitive decline.

OBJECTIVE

To assess the relationship between blood NfL and global cognition in individuals with possible vascular MCI (vMCI) throughout cardiac rehabilitation (CR). Additionally, NfL levels were compared to age/sex-matched cognitively unimpaired (CU) controls.

METHOD

Participants with coronary artery disease (vMCI or CU) were recruited at entry to a 24-week CR program. Global cognition was measured using the Montreal Cognitive Assessment (MoCA) and plasma NfL level (pg/ml) was quantified using a highly sensitive enzyme-linked immunosorbent assay.

RESULTS

Higher plasma NfL was correlated with worse MoCA scores at baseline (β = -.352, P = .029) in 43 individuals with vMCI after adjusting for age, sex, and education. An increase in NfL was associated with worse global cognition (b[SE] = -4.81[2.06], P = .023) over time, however baseline NfL did not predict a decline in global cognition. NfL levels did not differ between the vMCI (n = 39) and CU (n = 39) groups (F(1, 76) = 1.37, P = .245).

CONCLUSION

Plasma NfL correlates with global cognition at baseline in individuals with vMCI, and is associated with decline in global cognition during CR. Our findings increase understanding of NfL and neurobiological mechanisms associated with cognitive decline in vMCI.

Cardiac hemodynamics phenotypes and individual responses to training in coronary heart disease patients

BACKGROUND

In patients with coronary heart disease (CHD), individualized exercise training (ET) programs are strongly recommended to optimize peak oxygen uptake (V ̇ $$ \dot{\mathrm{V}} $$ O2peak) improvement and prognosis. However, the cardiac hemodynamic factors responsible for a positive response to training remain unclear. The aim of this study was to compare cardiac hemodynamic changes after an ET program in responder (R) versus non-responder (NR) CHD patients.

METHODS

A total of 72 CHD patients completed a 3-month ET program and were assessed by cycle ergometer cardiopulmonary exercise test (CPET:V ̇ $$ \dot{\mathrm{V}} $$ O2peak assessment) with impedance cardiography (ICG) for hemodynamic measurements before and after training. Cardiac hemodynamics (e.g., CO, CI, SV, ESV, EDV, and SVR) were measured by ICG during CPET. The R and NR groups were classified using the median change inV ̇ $$ \dot{\mathrm{V}} $$ O2peak (>the median for R and ≤the median for NR).

RESULTS

In the R group,V ̇ $$ \dot{\mathrm{V}} $$ O2peak (+17%, p < 0.001), CO, CI, SV, and HR increased by 17%, 17%, 13%, and 5%, respectively (p < 0.05) after the training program. In the NR group,V ̇ $$ \dot{\mathrm{V}} $$ O2peak, CO, CI, and SV increased by 0.5%, 5%, 8%, and 6%, respectively (p < 0.01). The SVR decreased in both groups (-19% in R and -11% in NR, p < 0.001).

CONCLUSION

Among CHD patients, the R group showed a better improvement in peak cardiac output via an increase in peak stroke volume and heart rate and a reduced systemic vascular resistance than the NR group. Different cardiac phenotype adaptations and clinical individual responses were identified in CHD patients according to the aerobic fitness responder's status.

Quantifying Improvement in V˙ o2peak and Exercise Thresholds in Cardiovascular Disease Using Reliable Change Indices

PURPOSE

Improving aerobic fitness through exercise training is recommended for the treatment of cardiovascular disease (CVD). However, strong justifications for the criteria of assessing improvement in key parameters of aerobic function including estimated lactate threshold (θ LT ), respiratory compensation point (RCP), and peak oxygen uptake (V˙ o2peak ) at the individual level are not established. We applied reliable change index (RCI) statistics to determine minimal meaningful change (MMC RCI ) cutoffs of θ LT , RCP, and V˙ o2peak for individual patients with CVD.

METHODS

Sixty-six stable patients post-cardiac event performed three exhaustive treadmill-based incremental exercise tests (modified Bruce) ∼1 wk apart (T1-T3). Breath-by-breath gas exchange and ventilatory variables were measured by metabolic cart and used to identify θ LT , RCP, and V˙ o2peak . Using test-retest reliability and mean difference scores to estimate error and test practice/exposure, respectively, MMC RCI values were calculated for V˙ o2 (mL·min -1. kg -1 ) at θ LT , RCP, and V˙ o2peak .

RESULTS

There were no significant between-trial differences in V˙ o2 at θ LT ( P = .78), RCP ( P = .08), or V˙ o2peak ( P = .74) and each variable exhibited excellent test-retest variability (intraclass correlation: 0.97, 0.98, and 0.99; coefficient of variation: 6.5, 5.4, and 4.9% for θ LT , RCP, and V˙ o2peak , respectively). Derived from comparing T1-T2, T1-T3, and T2-T3, the MMC RCI for θ LT were 3.91, 3.56, and 2.64 mL·min -1. kg -1 ; 4.01, 2.80, and 2.79 mL·min -1. kg -1 for RCP; and 3.61, 3.83, and 2.81 mL·min -1. kg -1 for V˙ o2peak . For each variable, MMC RCI scores were lowest for T2-T3 comparisons.

CONCLUSION

These MMC RCI scores may be used to establish cutoff criteria for determining meaningful changes for interventions designed to improve aerobic function in individuals with CVD.

Low serum brain-derived neurotrophic factor may predict poor response to cardiac rehabilitation in patients with cardiovascular disease

BACKGROUND

It has been shown that serum brain-derived neurotrophic factor (BDNF) is associated with skeletal muscle energy metabolism and that BDNF is a predictor of mortality in heart failure patients. However, little is known about the relationship between BDNF and cardiac rehabilitation (CR). Therefore, this study retrospectively investigated the effects of baseline serum BDNF levels on the CR-induced exercise capacity improvement in patients with cardiovascular disease (CVD).

METHODS

We assigned 99 CVD patients (mean age 71±12 years, male = 60) to Low, Middle, and High groups based on the tertiles of baseline BDNF levels. Cardiopulmonary exercise testing was done using supervised bicycle ergometer twice before and after 3 weeks of CR. Analysis of covariance (ANCOVA) followed by post-hoc analysis using Tukey's HSD test was conducted to assess the multivariate associations between baseline BDNF levels categorized by BDNF tertiles (as independent variable) and %increases in AT and peak VO2 after 3-week CR (as dependent variables) after adjustment for age and gender (as covariates), as a main statistical analysis of the present study.

RESULTS

The higher the baseline BDNF levels, the better nutritional status evaluated by the CONUT score (p<0.0001). Baseline anaerobic threshold (AT) and peak oxygen uptake (peak VO2) were similar among the three groups. ANCOVA followed by post-hoc analysis revealed that age- and gender-adjusted %increases in peak VO2 after 3-week CR were positively associated with baseline BDNF levels (p = 0.0239) and Low BDNF group showed significantly lower %increase in peak VO2 than High BDNF group (p = 0.0197). Significant association was not found between baseline BDNF and %increase in AT (p = 0.1379).

CONCLUSIONS

Low baseline BDNF levels were associated with malnutrition in CVD patients. A positive association between baseline BDNF levels and CR-induced increases in peak VO2 was found. It was suggested that CVD patients with low baseline BDNF levels may be poor responders to CR.

Cardiac rehabilitation: the gateway for secondary prevention

Cardiac rehabilitation (CR) is a multidisciplinary supervised programme which typically consists of tailored exercise and education on lifestyle management and risk factor modification in cardiac patients. Participation in CR reduces morbidity and mortality, while improving quality of life following major cardiovascular events. Despite the benefits of CR, it is underutilised, generally in the 20%-30% range for eligible patients. Participation and adherence rates are particularly suboptimal in vulnerable populations, such as those of lower socioeconomic status and women. Interventions such as automated referral to CR or hybrid/virtual programmes can increase enrolment to CR. This review summarises the components of CR and provides recommendations for providers regarding participation and adherence. To better engage a larger proportion of CR-eligible patients, CR programmes may need to expand or adjust ways to deliver secondary prevention.

Hemodynamic Response to Exercise Training in Heart Failure With Reduced Ejection Fraction Patients

Background

Supervised exercise training decreases total and cardiac mortality and increases quality of life of heart failure with reduced ejection fraction (HFrEF) patients. However, response to training is variable from one patient to another and factors responsible for a positive response to training remain unclear. The aims of the study were to compare cardiac hemodynamic changes after an exercise training program in responders (R) versus non-responders (NR) HFrEF patients, and to compare different discriminators used to assess response to training.

Methods

Seventy-six HFrEF patients (86% males, 57 ± 12 years) completed an exercise training program for 4 weeks. Patients underwent cardiopulmonary exercise testing (CPET) on a cycle ergometer before and after training. Cardiac hemodynamics were measured by impedance cardiography during CPET. The R and NR groups were classified using the median change in peak oxygen uptake (V̇O2peak).

Results

There were statistically significant differences in V̇O2peak (+35% vs. -1%, P < 0.0001) and in peaks of ventilation (+30% vs. +2%, P < 0.0001), cardiac output (COpeak) (+25% vs. +4%, P < 0.01), systolic blood pressure (+12% vs. +2%, P < 0.05), diastolic blood pressure (+9% vs. +4%, P < 0.05) and heart rate (+8% vs. +1%, P < 0.01) between R and NR after the training program. V̇O2peak was the best discriminator between R and NR (receiver operating characteristic (ROC) area under the curve (AUC) = 0.83, P < 0.0001), followed by COpeak (ROC AUC = 0.77, P < 0.0001).

Conclusion

V̇O2peak is the best discriminator between HFrEF R and NR patients after the training program. Responders showed improvements in peak hemodynamic parameters. These results pave the way for other studies to determine how the individualization of exercise training programs and peak hemodynamic parameters potentially linked to a better positive response status.

Factors Affecting Recovery of 6-Minute Walk Distance After Coronary Artery Bypass Grafting

Background: This single-center retrospective analysis investigated the number of days required for postoperative 6-minute walk distance (6MWD) to recover to preoperative values after coronary artery bypass grafting (CABG) and the factors influencing this recovery. Methods and Results: The 6MWD was measured in 101 patients (median age 69 years; 18 women) before and every day after CABG. Univariate and multivariate analyses were performed to identify factors affecting 6MWD recovery to preoperative values after CABG. The median number of days required for recovery of 6MWD after CABG was 9 (interquartile range 7-11 days). Patients were divided into 2 groups based on the median number of days required for recovery of 6MWD; there were 60 patients in the early recovery group (<9 days) and 41 in the "non-early" recovery group (38 who recovered after the median 9 days, and 3 who did not recover during hospitalization). Using univariate logistic regression analysis, diabetes (P=0.01), stroke (P=0.26), left ventricular ejection fraction (P=0.27), and grip strength (P=0.13) were selected for multivariate analysis. Multivariate logistic regression analysis revealed that diabetes (odds ratio 2.955; 95% confidence interval 1.208-7.229; P=0.02) was the only independent predictor of 6MWD recovery. Conclusions: Diabetes was the single factor influencing the recovery of postoperative 6MWD in patients undergoing CABG.

Predictors of Changes in Peak Oxygen Uptake After Outpatient Cardiac Rehabilitation: Importance of Cardiac Rehabilitation Attendance

Objective

To determine whether the number of cardiac rehabilitation (CR) sessions attended and selected clinical characteristics were predictive of patients who exhibited improvement in peak oxygen uptake (VO₂peak) after CR.

Patients and Methods

Using the Rochester Epidemiology Project records-linkage system, we identified all consecutive patients aged 18 years or older from Olmsted County, Minnesota, who underwent cardiopulmonary exercise testing before and after CR from 1999 to 2017. Regression models were created to assess the clinical predictors of VO₂peak improvement (>0% baseline) after CR.

Results

The analysis included 671 patients, of which 524 (78%) patients exhibited VO₂peak improvement after CR. The significant univariate predictors of VO₂peak improvement included younger age (odds ratio [OR], 0.98; 95% CI, 0.96-0.99), lower pre-CR VO₂peak (OR, 0.96; 95% CI, 0.94-0.99), and no history of peripheral artery disease (OR, 0.50; 95% CI, 0.31-0.81) (all, P<.005). The significant independent predictors of VO₂peak improvement from the multivariable analysis included the number of CR sessions (OR, 1.04; 95% CI, 1.02-1.05), younger age (OR, 0.96; 95% CI, 0.94-0.98), lower pre-CR VO₂peak (OR, 0.92; 95% CI, 0.89-0.95), and no history of peripheral artery disease (OR, 0.47; 95% CI, 0.28-0.78) (all, P<.005).

Conclusion

These findings highlight the importance of patient participation in CR sessions and individual clinical characteristics in influencing VO₂peak improvement after CR in patients with cardiovascular disease.

Relation of a Maximal Exercise Test to Change in Exercise Tolerance During Cardiac Rehabilitation

The purpose of this study was to test the hypothesis that an individualized exercise training target heart rate (HR) based on a maximal graded exercise test (GXT) is associated with greater improvements in exercise tolerance during cardiac rehabilitation (CR) compared with no GXT. In this retrospective study, we identified patients who completed 9 to 36 visits of CR between 2001 and 2016, with a length of stay ≤18 weeks and a visit frequency of 1 to 3 days per week. Patients were grouped based on whether their exercise was guided by a target HR determined from a GXT. To assess the relation between GXT and change in exercise training metabolic equivalents of task (METs), we used generalized linear models adjusted for age, gender, race, referral reason, CR visits, CR frequency, METs at start, CR location, and year of participation. Out of 4,455 patients (37% female, 48% White, median age = 62 years), 53% were prescribed a target HR based on a GXT. Compared with no GXT, a GXT was associated with a significantly greater increase in covariate-adjusted METs during CR and percentage change from start (+0.44 METs [95% confidence interval [CI] 0.38 to 0.51] and +17% [95% CI 14% to 19%], respectively). In a sensitivity analysis limited to patients with 24 to 36 visits at ≥2 days per week (n = 1,319), a GXT was associated with a significantly greater increase in covariate-adjusted exercise training METs (+0.51 [95% CI 0.36 to 0.66]; +19% [95% CI 13% to 24%]). In conclusion, to maximize the potential increase in exercise capacity during CR, patients should undergo a GXT to determine an individualized exercise training target HR.

The effects of early rehabilitation on functional exercise tolerance in decompensated heart failure patients: Results of a multicenter randomized controlled trial (ERIC-HF study)

Objective

To analyze (1) the effect of an aerobic training program on functional exercise tolerance in decompensated heart failure (DHF) patients; (2) to assess the effects of an aerobic training program on functional independence; and (3) dyspnea during activities of daily living.

Design

A randomized controlled clinical trial with follow-up at discharge.

Settings

Eight hospitals. Recruitment took place between 9/ 2017 and 3/2019.

Group Assignments

Patients with DHF who were admitted to the hospital, were randomly assigned to usual rehabilitation care guideline recommended (control group) or aerobic training program (exercise group).

Main outcome

Functional exercise tolerance was measured with a 6-min walking test at discharge.

Results

In total 257 patients with DHF were included, with a mean age of 67 ± 11 years, 84% (n = 205) had a reduced ejection fraction and the hospital stay was 16 ± 10 days. At discharge, patients in the intervention group walked further compared to the control group (278 ± 117m vs 219 ± 115m, p < 0.01) and this difference stayed significant after correcting for confounders (p < 0.01). A significant difference was found favoring the exercise group in functional independence (96 ± 7 vs 93 ± 12, p = 0.02) and dyspnea associated to ADL (13 ± 5 vs 17 ± 7, p < 0.01) and these differences persisted after correcting for baseline values and confounders (functional independence p < 0.01; dyspnea associated with ADL p = 0.02).

Conclusion

The ERIC-HF program is safe, feasible, and effective in increasing functional exercise tolerance and functional independence in hospitalized patients admitted due to DHF.

Sex Differences in Cardiac Rehabilitation Outcomes

Cardiovascular disease is a leading cause of morbidity and mortality in males and females in the United States and globally. Cardiac rehabilitation (CR) is recommended by the American Heart Association/American College of Cardiology for secondary prevention for patients with cardiovascular disease. CR participation is associated with improved cardiovascular disease risk factor management, quality of life, and exercise capacity as well as reductions in hospital admissions and mortality. Despite these advantageous clinical outcomes, significant sex disparities exist in outpatient phase II CR programming. This article reviews sex differences that are present in the spectrum of care provided by outpatient phase II CR programming (ie, from referral to clinical management). We first review CR participation by detailing the sex disparities in the rates of CR referral, enrollment, and completion. In doing so, we discuss patient, health care provider, and social/environmental level barriers to CR participation with a particular emphasis on those barriers that majorly impact females. We also evaluate sex differences in the core components incorporated into CR programming (eg, patient assessment, exercise training, hypertension management). Next, we review strategies to mitigate these sex differences in CR participation with a focus on automatic CR referral, female-only CR programming, and hybrid CR. Finally, we outline knowledge gaps and areas of future research to minimize and prevent sex differences in CR programming.

Exercise training in cardiac rehabilitation: Setting the right intensity for optimal benefit

Cardiac rehabilitation (CR) programs are recommended standard-of-care by all major cardiovascular medicine professional organizations. Exercise training is the cornerstone for CR, with aerobic training being the primary form of training. The benefits of exercise training are multiple; however, improved cardiorespiratory fitness is of utmost importance. Moderate-intensity continuous training, supplemented with resistance training, has traditionally been the most common form of exercise training in CR. This review discusses the role of aerobic exercise training in CR and the importance of effective and personalized exercise prescription for optimized results. We also focus on the benefits and utility of high-intensity interval training across different clinical populations commonly seen in the CR setting.

Cardiorespiratory Responses During High-Intensity Interval Training Prescribed by Rating of Perceived Exertion in Patients After Myocardial Infarction Enrolled in Early Outpatient Cardiac Rehabilitation

Objective: We aimed to determine the cardiorespiratory responses during, and adaptations to, high-intensity interval training (HIIT) prescribed using ratings of perceived exertion (RPE) in patients after myocardial infarction (MI) during early outpatient cardiac rehabilitation (CR).

Methods: We prospectively recruited 29 MI patients after percutaneous coronary intervention who began CR within 2 weeks after hospital discharge. Eleven patients (seven men; four women; age: 61 ± 11 yrs) who completed ≥24 supervised HIIT sessions with metabolic gas exchange measured during HIIT once weekly for 8 weeks and performed pre- and post- CR cardiopulmonary exercise tests were included in the study. Each HIIT session consisted of 5–8 high-intensity intervals [HIIs, 1-min RPE 14–17 (Borg 6–20 scale)] and low-intensity intervals (LIIs, 4-min RPE < 12). Metabolic gas exchange, heart rate (HR), and blood pressure during HIIT were measured.

Results: The mean oxygen uptake (V˙O₂) during HIIs across 88 sessions of HIITs [91 (14)% of V˙O_2peak, median (interquartile range, IQR)] was significantly higher than the lower limit of target V˙O₂ zone (75% of V˙O_2peak) recommended for the HII (p < 0.001). Exercise intensity during RPE-prescribed HIITs, determined as %V˙O_2peak, was highly repeatable with intra-class correlations of 0.95 (95% CI 0.86– 0.99, p < 0.001). For cardiorespiratory adaptations from the first to the last session of HIIT, treadmill speed, treadmill grade, treadmill power, V˙O_2HII, %V˙O_2peak, and V_E during HIIs were increased (all p < 0.05), while no difference was found for HR, %HR_peak and systolic blood pressure (all p > 0.05). V˙O_2peak increased by an average of 9% from pre-CR to post-CR. No adverse events occurred.

Conclusion: Our results demonstrate that HIIT can be effectively prescribed using RPE in MI patients during early outpatient CR. Participation in RPE-prescribed HIIT increases exercise workload and V˙O₂ during exercise training without increased perception of effort or excessive increases in heart rate or blood pressure.

Mechanisms of Exercise Capacity Improvement after Cardiac Rehabilitation Following Myocardial Infarction Assessed with Combined Stress Echocardiography and Cardiopulmonary Exercise Testing

Cardiac rehabilitation (CR) is indicated in all patients after acute myocardial infarction (AMI) to improve prognosis and exercise capacity (EC). Previous studies reported that up to a third of patients did not improve their EC after CR (non-responders). Our aim was to assess the cardiac and peripheral mechanisms of EC improvement after CR using combined exercise echocardiography and cardiopulmonary exercise testing (CPET-SE). The responders included patients with an improved EC assessed as a rise in peak oxygen uptake (VO₂) ≥ 1 mL/kg/min. Peripheral oxygen extraction was calculated as arteriovenous oxygen difference (A-VO₂Diff). Out of 41 patients (67% male, mean age 57.5 ± 10 years) after AMI with left ventricular ejection fraction (LVEF) ≥ 40%, 73% improved their EC. In responders, peak VO₂ improved by 27% from 17.9 ± 5.2 mL/kg/min to 22.7 ± 5.1 mL/kg/min, p < 0.001, while non-responders had a non-significant 5% decrease in peak VO₂. In the responder group, the peak exercise heart rate, early diastolic myocardial velocity at peak exercise, LVEF at rest and at peak exercise, and A-VO₂Diff at peak exercise increased, the minute ventilation to carbon dioxide production slope decreased, but the stroke volume and cardiac index were unchanged after CR. Non-responders had no changes in assessed parameters. EC improvement after CR of patients with preserved LVEF after AMI is associated with an increased heart rate response and better peripheral oxygen extraction during exercise.

Sex differences in physical and mental health following high-intensity interval training in adults with cardiovascular disease who completed cardiac rehabilitation

This pre-post study examined sex-differences in peak aerobic power (V̇O2peak) and physical- and mental-health outcomes in adults with cardiovascular disease who completed high-intensity interval training (HIIT)-based cardiac rehabilitation. HIIT consisted of 25 minutes of alternating higher- (4×4 minutes 85-95% heart rate peak (HRpeak)) and lower- (3×3 minutes 60-70% HRpeak) intensity intervals twice weekly for 10 weeks. V̇O2peak estimated from a graded exercise test using the American College of Sports Medicine equation, body mass index (BMI), waist circumference, blood pressure, blood biomarkers and anxiety and depression were assessed at baseline and follow-up. Linear mixed-effects models for repeated measures were performed to examine differences over time between sexes. Of 140 participants (mean ± standard deviation: 58 ± 9 years), 40 were female. Improvements in V̇O2peak did not differ between sexes (interaction: p = 0.273, females: 28.4 ± 6.4 to 30.9 ± 7.6; males: 34.3 ± 6.3 to 37.4 ± 6.0 mL/kg/min). None of the time by sex interactions were significant. Significant main effects of time showed reductions in waist circumference, triglycerides, low-density lipoprotein (LDL), total cholesterol (TC)/high-density lipoprotein (HDL) and anxiety, and increases in V̇O2peak and HDL from baseline to follow-up. Significant main effects of sex revealed smaller V̇O2peak, BMI and waist circumference, and higher LDL, TC and HDL in females than males. HIIT led to similar improvements in estimated V̇O2peak (females: 8.8%, males: 9.0%) and additional health outcomes between sexes. Novelty: HIIT-based cardiac rehabilitation led to similar improvements in estimated V̇O2peak and other physical and mental health outcomes between sexes. The number of sessions attended was high (>70%) and did not differ by sex. Both sexes showed good compliance with the exercise protocol (HR target).

Underutilization of Cardiac Rehabilitation in Women: BARRIERS AND SOLUTIONS

PURPOSE

Despite the known benefits of cardiac rehabilitation (CR), it remains underutilized particularly among women. The aim of this review was to provide an overview regarding women in CR, addressing barriers that may affect enrollment and attendance as well as to discuss the training response and methods to optimize exercise-related benefits of CR.

REVIEW METHODS

The review examines original studies and meta-analyses regarding women in CR.

SUMMARY

Women are less likely to engage in CR compared with men, and this may be attributed to lack of referral or psychosocial barriers on the part of the patient. Furthermore, despite having lower levels of fitness, women do not improve their fitness as much as men in CR. This review summarizes the current literature and provides recommendations for providers regarding participation and adherence as well as optimal methods for exercise training for women in CR.

Sex Differences in Cardiometabolic Health Indicators after HIIT in Patients with Coronary Artery Disease

PURPOSE

Cardiorespiratory fitness (CRF) is an independent predictor of mortality, and females typically achieve smaller improvements in CRF than males after exercise-based cardiac rehabilitation. High-intensity interval training (HIIT) has been shown to produce superior improvements in CRF than traditional cardiac rehabilitation, but the sex differences are unknown. The purpose of this systematic review and meta-analysis was to evaluate sex differences for changes in CRF and cardiometabolic health indicators after HIIT in adults with coronary artery disease (CAD).

METHODS AND RESULTS

A systemic search of five electronic databases for studies examining the effect of HIIT on measured CRF and cardiometabolic health indicators in adults with CAD was performed. Data (published and unpublished) from 14 studies were included in the meta-analyses with approximately eightfold greater male than female participation (n = 836 vs n = 103). Males with CAD achieved a near-significant absolute improvement in CRF (mean difference [MD] = 1.07, 95% confidence interval [CI] = -0.08 to 2.23 mL·kg-1⋅min-1, P = 0.07) after HIIT when compared with control; there were insufficient data to conduct such an analysis in females. Significantly smaller improvements in CRF were experienced by females than males (MD = -1.10, 95% CI = -2.08 to -0.12 mL·kg-1⋅min-1, P = 0.03); there was no sex difference for the relative (percentage) change in CRF after HIIT. Females achieved significantly smaller reductions in body mass index (MD = -0.25, 95% CI = -0.03 to -0.47 kg·m-2, P = 0.02) and fasting blood glucose (MD = -0.38, 95% CI = -0.05 to -0.72, P = 0.03); no sex differences were observed for other cardiometabolic health indicators.

CONCLUSION

There are no sex differences for relative improvements in CRF after HIIT; however, females are greatly underrepresented in trials. Future studies should increase female participation and perform sex-based analyses to determine sex-specific outcomes following HIIT.

UK cardiac rehabilitation fit for purpose? A community-based observational cohort study

OBJECTIVES

This study aimed to characterise the exercise performed in UK cardiac rehabilitation (CR) and explore relationships between exercise dose and changes in physiological variables.

DESIGN

Observational cohort study.

SETTING

Outpatient community-based CR in Leeds, UK. Rehabilitation sessions were provided twice per week for 6 weeks.

PARTICIPANTS

Sixty patients (45 male/15 female 33-86 years) were recruited following referral to local outpatient CR.

OUTCOME MEASURES

The primary outcome was heart rate achieved during exercise sessions. Secondary outcomes were measured before and after CR and included incremental shuttle walk test (ISWT) distance and speed, blood pressure, brachial artery flow-mediated dilatation, carotid arterial stiffness and accelerometer-derived habitual physical activity behaviours.

RESULTS

The mean % of heart rate reserve patients exercised at was low and variable at the start of CR (42%±16 %) and did not progress by the middle (48%±17 %) or end (48%±16 %) of the programme. ISWT performance increased following CR (440±150 m vs 633±217 m, p<0.001); however, blood pressure, body weight, endothelial function, arterial stiffness and habitual physical activity behaviours were unchanged following 6 weeks of CR (p>0.05).

CONCLUSION

Patients in a UK CR cohort exercise at intensities that are variable but generally low. The exercise dose achieved using this CR format appears inadequate to impact markers of health. Attending CR had no effect on physical activity behaviours. Strategies to increase the dose of exercise patients achieve during CR and influence habitual physical activity behaviours may enhance the effectiveness of UK CR.

Response to Exercise Training During Cardiac Rehabilitation Differs by Sex

PURPOSE

Directly measured peak aerobic capacity or oxygen uptake is a powerful predictor of prognosis in individuals with cardiovascular disease. Women enter phase 2 cardiac rehabilitation (CR) with lower and their response to training, compared with men, is equivocal. We analyzed at entry and exit in patients participating in CR and improvements by diagnosis to assess training response. We also identified sex differences that may influence change in .

METHODS

The cohort included consecutive patients enrolled in CR between January 1996 and December 2015 who performed entry exercise tolerance tests. Data collected included demographics, index diagnosis, , and exercise training response.

RESULTS

The cohort consisted of 3925 patients (24% female). There was a significant interaction between baseline and diagnosis (P < .001), with percutaneous coronary intervention and myocardial infarction greater than other diagnoses. Surgical patients demonstrated greater improvement in than nonsurgical diagnoses (n = 1789; P < .001). Women had lower than men for all diagnoses (P < .02) and demonstrated less improvement (13 vs 17%, P < .001). Percent improvement using estimated metabolic equivalents of task (METs) were similar for women and men (33 vs 31%, P = NS). Despite overall increases in , 18% of patients (24% women, 16% men) failed to demonstrate any improvement (exit ≤ entry ).

CONCLUSIONS

While there were no differences in training effect estimated by METs, directly measured showed a significantly lower training response for women despite adjusting for covariates. In addition, 18% of patients did not see any improvement in . Alternatives to traditional CR exercise programming need to be considered.

Moderate-intensity continuous exercise is superior to high-intensity interval training in the proportion of VO2peak responders after ACS

INTRODUCTION AND OBJECTIVES

We compared the effects of 12 weeks of low-volume high-intensity interval training (LV-HIIT) vs moderate-intensity continuous exercise training (MICET) on cardiopulmonary exercise test parameters and the proportion of non/low responders (NLR) to exercise training in post-acute coronary syndrome (ACS) patients.

METHODS

Patients with a recent ACS were randomized to LV-HIIT, MICET, or a usual care group. LV-HIIT consisted of 2 to 3 sets of 6 to 10minutes with repeated bouts of 15 to 30seconds at 100% of peak workload alternating with 15 to 30seconds of passive recovery. Cardiopulmonary exercise test parameters were assessed, and key exercise variables were calculated. Training response was assessed according to the median VO_2peak change post vs pretraining in the whole cohort (stratification NLR vs high response).

RESULTS

Fifty patients were included in the analysis (LV-HIIT, n=23; MICET, n=18; usual care, n=9) and 74% were male. The proportion of NLR was higher in the LV-HIIT group than in the MICET group (LV-HIIT 61%, MICET 21%, and usual care 80%; P=.0040). VO_2peak-dependent variables (VO_2peak, percent-predicted VO_2peak) improved in both training groups (P=.002 and P <.0001 for time with LV-HIIT and MICET, respectively), but the improvement was more pronounced with MICET (P=.004 and P=.001 for interaction, respectively). The ΔVO₂/Δworkload slope improved only with MICET (P=.021).

CONCLUSIONS

In patients with a recent ACS, several prognostic VO_2peak-dependent variables were improved after LV-HIIT, but the improvement was more pronounced or only found after MICET. Low-volume HIIT resulted in a higher proportion of NLR than isocaloric MICET. Clinical trialsregistered at ClinicalTrials.gov (Identifiers: NCT03414996 and NCT02048696).

Non-linear is not superior to linear aerobic training periodization in coronary heart disease patients

Background

We aimed to compare: (1) two different periodized aerobic training protocols (linear (LP) versus non-linear (NLP)) on the cardiopulmonary exercise response in patients with coronary heart disease; (2) the proportion of responders between both training protocols.

Design

A randomized controlled trial.

Methods

A total of 39 coronary heart disease patients completed either LP ( n = 20, 65 ± 10 years) or NLP ( n = 19, 66 ± 5 years). All patients completed a cardiopulmonary exercise testing with gas exchange measurements. Patients underwent a 12-week supervised exercise program including an isoenergetic aerobic periodized training and a similar resistance training program, 3 times/week. Weekly energy expenditure was constantly increased in the LP group for the aerobic training, while it was deeply increased and intercepted with a recovery week each fourth week in the NLP group. Peak oxygen uptake (peak V̇O2), oxygen uptake efficiency slope, ventilatory efficiency slope (V̇E/V̇CO2 slope), V̇O2 at the first (VT1) and second (VT2) ventilatory thresholds, and oxygen pulse (O2 pulse) were measured. Responders were determined according the median value of the Δpeak V̇O2 (mL.min−1.kg−1).

Results

We found similar improvement for peak V̇O2 (LP: +8.1%, NLP: +5.3%, interaction: p = 0.37; time: p < 0.001) and for oxygen uptake efficiency slope, VT1, VT2 and O2 pulse in both groups (interaction: p > 0.05; time: p < 0.05) with a greater effect size in the LP group. The proportion of non-, low and high responders was similar between groups ( p = 0.29).

Conclusion

In contrast to the athletes, more variation (NLP) does not seem necessary for greater cardiopulmonary adaptations in coronary heart disease patients.

Progression of Exercise Training in Early Outpatient Cardiac Rehabilitation: AN OFFICIAL STATEMENT FROM THE AMERICAN ASSOCIATION OF CARDIOVASCULAR AND PULMONARY REHABILITATION

Aerobic and resistance exercise training is a cornerstone of early outpatient cardiac rehabilitation (CR) and provides impressive benefits for patients. The components of the exercise prescription for patients with cardiovascular diseases are provided in guideline documents from several professional organizations and include frequency (how many sessions per week); intensity (how hard to exercise); time (duration of the exercise training session); type (modalities of exercise training); volume (the total amount or dose of exercise); and progression (the rate of increasing the dose of exercise). The least discussed, least appreciated, and most challenging component of the exercise prescription for CR health care professionals is the rate of progression of the dose of exercise. One reason for this observation is the heterogeneity of patients who participate in CR. All components of the exercise prescription should be developed specifically for each individual patient. This statement provides an overview of the principles of exercise prescription for patients in CR with special emphasis on the rate of progression. General recommendations for progression are given and patient case examples are provided to illustrate the principles of progression in exercise training.

Cardiac rehabilitation fitness changes and subsequent survival

Aims

Assessments of cardiac rehabilitation (CR) in coronary heart disease (CHD) cohorts usually examine mortality in aggregate. This study examines the prognosis and characteristics of patients who enrolled and completed CR, stratified by their level of improvement in cardiorespiratory fitness (CRF) by examining the characteristics, outcomes and predictors of non-response in CRF (NonRes) compared with low-responders (LowRes) and high-responders (HighRes) after CR.

Methods and results

A total of 1171 CHD patients were referred for a phase II CR programme after therapy for an acute coronary syndrome, coronary artery bypass graft procedure or a percutaneous coronary intervention between 1 January 2000 and 30 June 2013 underwent cardiopulmonary exercise testing before and after CR. This cohort was divided according to absolute improvements in CRF (i.e. change in peak oxygen consumption expressed in mL⋅kg-1⋅min-1). Mortality was analysed after 0.5-13.4 years of follow-up (mean 6.4 years). A total of 266 (23%) subjects were NonRes. After adjustment for body mass index, age, gender, left ventricular ejection fraction and baseline CRF, NonRes, and LowRes had a statistically significant three-fold and two-fold higher mortality, respectively, when compared with HighRes (HighRes 8% vs. LowRes 17% vs. NonRes 22%; P < 0.001). Age, female gender, baseline CRF, hostility, and presence of diabetes were significant predictors of NonRes and LowRes. In addition, higher waist circumference was a predictor of NonRes.

Conclusion

Significant proportions of subjects referred to CR have no/low improvement in CRF and higher associated mortality risks. Greater attention is required to increase improvements in CRF following CR and avoid NonRes.

Improvements in fitness are not obligatory for exercise training-induced improvements in CV risk factors

The purpose of this study was to assess whether changes in physical fitness relate to changes in cardiovascular risk factors following standardized, center-based and supervised exercise training programs in subjects with increased cardiovascular risk. We pooled data from exercise training studies of subjects with increased cardiovascular risk (n = 166) who underwent 8-52 weeks endurance training. We determined fitness (i.e., peak oxygen uptake) and traditional cardiovascular risk factors (body mass index, blood pressure, total cholesterol, high-density lipoprotein cholesterol), before and after training. We divided subjects into quartiles based on improvement in fitness, and examined whether these groups differed in terms of risk factors. Associations between changes in fitness and in cardiovascular risk factors were further tested using Pearson correlations. Significant heterogeneity was apparent in the improvement of fitness and individual risk factors, with nonresponder rates of 17% for fitness, 44% for body mass index, 33% for mean arterial pressure, 49% for total cholesterol, and 49% for high-density lipoprotein cholesterol. Neither the number, nor the magnitude, of change in cardiovascular risk factors differed significantly between quartiles of fitness change. Changes in fitness were not correlated with changes in cardiovascular risk factors (all P > 0.05). Our data suggest that significant heterogeneity exists in changes in peak oxygen uptake after training, while improvement in fitness did not relate to improvement in cardiovascular risk factors. In subjects with increased cardiovascular risk, improvements in fitness are not obligatory for training-induced improvements in cardiovascular risk factors.

Strategies for supporting intervention fidelity in the rehabilitation therapy in older acute heart failure patients (REHAB-HF) trial

INTRODUCTION

Acute decompensated heart failure (ADHF) is the leading cause of hospitalization in older adults. Rehabilitation Therapy in Older Acute Heart Failure Patients (REHAB-HF) trial is a multi-site clinical trial to determine if physical rehabilitation intervention in older patients with ADHF improves physical function and reduces rehospitalizations. The REHAB-HF intervention aims to improve functional performance utilizing reproducible and progressive exercises that are individually tailored to the patient's physiological and physical capabilities. Fidelity of the intervention is essential to the trial's integrity and success. Maintaining fidelity is challenged by the complex, multi-domain design of the intervention implemented across multiple sites and delivered to an older, heterogeneous participant pool with severe underlying disease and multi-morbidity.

METHODS/DESIGN

Given the dynamic nature of the REHAB-HF intervention, rigorous fidelity strategies were formulated. In this paper we summarize the specific strategies that REHAB-HF is using to meet the National Institutes of Health (NIH) Behavior Change Consortium Treatment Fidelity Workgroup recommendations in 5 key areas: 1) ensuring the intervention dose is consistent across participants, 2) standardizing interventionist training, 3) monitoring intervention delivery, 4) evaluating participants' understanding of information provided, and 5) ensuring that participants use the skills taught in the intervention.

DISCUSSION

Effective intervention fidelity strategies are essential to the reliability and validity of physical function intervention trials. The REHAB-HF trial has developed comprehensive, specific strategies to ensure intervention fidelity despite a challenging study population and a complex intervention to meet NIH recommendations. This experience provides a strong working model for future physical function intervention trials.

CHA2DS2-VASc score and exercise capacity of patients with coronary artery disease participating in cardiac rehabilitation programs

BACKGROUND

Exercise based cardiac rehabilitation improves prognosis and quality of life in patients with coronary artery disease. We aimed to investigate whether the CHA2DS2-VASc score may be a predictor of improvement in exercise capacity in acute coronary syndrome (ACS) patients participating in a cardiac rehabilitation program.

METHODS

Included were patients following a hospital admission due to ACS and were subsequently referred for an exercise based cardiac rehabilitation during 2010-2015. Participants were divided into three groups of low (1-2), intermediate (3) and high (4≤) CHA2DS2-VASc score. Exercise capacity was evaluated by a treadmill stress test at baseline and following 9 months. The primary endpoint was the percent of patients who achieved at least 25% improvement in exercise capacity.

RESULTS

The 597 patients included in the study had a mean age of 65.5±9.3 years and consisted of 22.5% women. The primary endpoint of at least 25% improvement in exercise capacity following 9 months of cardiac rehabilitation occurred more frequently in patients in the high CHA2DS2-VASc group compared to the intermediate and low CHA2DS2-VASc score groups (47.3, 29.9 and 36.1% in the high, intermediate and low CHA2DS2-VASc score groups respectively, P=0.002).

CONCLUSION

The CHA2DS2-VASc score may serve as a predictor of exercise capacity improvement. Its use for tailoring specific cardiac rehabilitation programs for ACS patients may yield further improvement in functional capacity and better utilization of resources.

Rehabilitation Therapy in Older Acute Heart Failure Patients (REHAB-HF) trial: Design and rationale

BACKGROUND

Acute decompensated heart failure (ADHF) is a leading cause of hospitalization in older persons in the United States. Reduced physical function and frailty are major determinants of adverse outcomes in older patients with hospitalized ADHF. However, these are not addressed by current heart failure (HF) management strategies and there has been little study of exercise training in older, frail HF patients with recent ADHF.

HYPOTHESIS

Targeting physical frailty with a multi-domain structured physical rehabilitation intervention will improve physical function and reduce adverse outcomes among older patients experiencing a HF hospitalization.

STUDY DESIGN

REHAB-HF is a multi-center clinical trial in which 360 patients ≥60 years hospitalized with ADHF will be randomized either to a novel 12-week multi-domain physical rehabilitation intervention or to attention control. The goal of the intervention is to improve balance, mobility, strength and endurance utilizing reproducible, targeted exercises administered by a multi-disciplinary team with specific milestones for progression. The primary study aim is to assess the efficacy of the REHAB-HF intervention on physical function measured by total Short Physical Performance Battery score. The secondary outcome is 6-month all-cause rehospitalization. Additional outcome measures include quality of life and costs.

CONCLUSIONS

REHAB-HF is the first randomized trial of a physical function intervention in older patients with hospitalized ADHF designed to determine if addressing deficits in balance, mobility, strength and endurance improves physical function and reduces rehospitalizations. It will address key evidence gaps concerning the role of physical rehabilitation in the care of older patients, those with ADHF, frailty, and multiple comorbidities.

Very short/short-term benefit of inpatient/outpatient cardiac rehabilitation programs after coronary artery bypass grafting surgery

BACKGROUND

Exercise-based rehabilitation is an important part of treatment patients following coronary artery bypass graft (CABG) surgery.

HYPOTHESIS

To evaluate effect of very short/short-term exercise training on cardiopulmonary exercise testing (CPET) parameters.

METHODS

We studied 54 consecutive patients with myocardial infarction (MI) treated with CABG surgery referred for rehabilitation. The study population consisted of 50 men and 4 women (age 57.72 ± 7.61 years, left ventricular ejection fraction 55% ± 5.81%), who participated in a 3-week clinical and 6-month outpatient cardiac rehabilitation program. The Inpatient program consisted of cycling 7 times/week and daily walking for 45 minutes. The outpatient program consisted mainly of walking 5 times/week for 45 minutes and cycling 3 times/week. All patients performed symptom-limited CPET on a bicycle ergometer with a ramp protocol of 10 W/minute at the start, for 3 weeks, and for 6 months.

RESULTS

After 3 weeks of an exercise-based cardiac rehabilitation program, exercise tolerance improved as compared to baseline, as well as peak respiratory exchange ratio. Most importantly, peak VO₂ (16.35 ± 3.83 vs 17.88 ± 4.25 mL/kg/min, respectively, P < 0.05), peak VCO₂ (1.48 ± 0.40 vs 1.68 ± 0.43, respectively, P < 0.05), peak ventilatory exchange (44.52 ± 11.32 vs 52.56 ± 12.37 L/min, respectively, P < 0.05), and peak breathing reserve (52.00% ± 13.73% vs 45.75% ± 14.84%, respectively, P < 0.05) were also improved. The same improvement trend continued after 6 months (respectively, P < 0.001 and P < 0.0001). No major adverse cardiac events were noted during the rehabilitation program.

CONCLUSIONS

Very short/short-term exercise training in patients with MI treated with CABG surgery is safe and improves functional capacity.

History of erectile dysfunction as a predictor of poor physical performance after an acute myocardial infarction

Background Erectile dysfunction may predict future cardiovascular events and indicate the severity of coronary artery disease in middle-aged men. The aim of this study was to evaluate whether erectile dysfunction (expression of generalized macro- and micro-vascular pathology) could predict reduced effort tolerance in patients after an acute myocardial infarction. Patients and methods One hundred and thirty-nine male patients (60 ± 12 years old), admitted to intensive cardiac rehabilitation 13 days after a complicated acute myocardial infarction, were evaluated for history of erectile dysfunction using the International Index of Erectile Function questionnaire. Their physical performance was assessed by means of two six-minute walk tests (performed two weeks apart) and by a symptom limited cardiopulmonary exercise test (CPET). Results Patients with erectile dysfunction (57% of cases) demonstrated poorer physical performance, significantly correlated to the degree of erectile dysfunction. After cardiac rehabilitation, they walked shorter distances at the final six-minute walk test (490 ± 119 vs. 564 ± 94 m; p < 0.001); at CPET they sustained lower workload (79 ± 28 vs. 109 ± 34 W; p < 0.001) and reached lower oxygen uptake at peak effort (18 ± 5 vs. 21 ± 5 ml/kg per min; p = 0.003) and at anaerobic threshold (13 ± 3 vs.16 ± 4 ml/kg per min; p = 0.001). The positive predictive value of presence of erectile dysfunction was 0.71 for low peak oxygen uptake (<20 ml/kg per min) and 0.69 for reduced effort capacity (W-max <100 W). Conclusions As indicators of generalized underlying vascular pathology, presence and degree of erectile dysfunction may predict the severity of deterioration of effort tolerance in post-acute myocardial infarction patients. In the attempt to reduce the possibly associated long-term risk, an optimization of type, intensity and duration of cardiac rehabilitation should be considered.

Financial incentives to promote cardiac rehabilitation participation and adherence among Medicaid patients

PURPOSE

Cardiac rehabilitation (CR) improves medical outcomes after myocardial infarction or coronary revascularization. Lower socioeconomic status (SES) patients are less likely to participate in and complete CR. The aim of this study was to test whether financial incentives may increase participation and adherence to CR among lower-SES patients.

METHODS

Patients eligible to participate in CR with Medicaid insurance coverage were approached for inclusion. Patients were placed on an escalating incentive schedule of financial incentives contingent upon CR attendance. CR participation was compared to a usual care group of 101 Medicaid patients eligible for CR in the 18months prior to the study. Attendance (participating in ≥one CR sessions) and adherence (sessions completed out of 36) were compared between groups. The study was conducted in Vermont, USA, 2013-2015.

RESULTS

Of 13 patients approached to be in the study and receive incentives, 10 (77%) agreed to participate. All 10 patients completed at least one session of CR, significantly greater than the 25/101 (25%) in the control condition (p<0.001). Of patients in both groups who attended at least one session of CR, adherence was higher in the intervention group (average of 31.1 sessions completed vs. 13.6 in the control group, p<0.001). CR completion rates were also higher during the intervention with 8 of 10 (80%) intervention patients completing all 36 sessions compared to only 2 of 25 (8%) control patients (p<0.001).

CONCLUSIONS

Financial incentives may be an efficacious strategy for increasing CR participation and adherence among Medicaid patients.

Cardiac Rehabilitation After Heart Valve Surgery: COMPARISON WITH CORONARY ARTERY BYPASS GRAFT PATIENTS

PURPOSE

Coronary artery bypass graft (CABG) surgery patients participating in cardiac rehabilitation (CR) experience improvements in aerobic fitness, but there has been little study of outcomes for heart valve (HV) surgical patients. The primary aims of this study were to evaluate baseline peak aerobic capacity for HV patients participating in CR and to compare outcomes between HV and CABG patients.

METHODS

Five hundred seventy-six consecutive patients who underwent HV surgery (n = 125), HV plus CABG surgery (n = 57), or CABG surgery (n = 394), all with classic sternotomy and enrolled in CR, were prospectively studied. Changes in outcomes were assessed for individuals who completed CR (n = 313).

RESULTS

HV patients were significantly older and had a greater percentage of females than the CABG-only group. Combining HV and HV + CABG groups, valvular disorders included 134 mitral, 39 aortic, and 8 combined abnormalities (mitral and aortic). For the entire cohort, the mean number of CR exercise sessions attended was 23.6 ± 11.7. Peak oxygen uptake ((Equation is included in full-text article.)) increased 19.5% from 17.4 ± 4.4 to 20.8 ± 5.5 mLO2·kg(-1)·min(-1) (P < .0001). Improvement in peak (Equation is included in full-text article.)with CR exercise training was similar between the 3 groups of patients. Within the group of patients who had HV surgery, percentage change in peak (Equation is included in full-text article.)was not significantly different between the 3 types of valvular abnormalities (ie, mitral [19.2%], aortic [24.4%], and mitral + aortic [21.9%]).

CONCLUSIONS

HV surgery patients achieve similar improvement in aerobic fitness from participating in CR exercise training as individuals who had CABG. The observed improvements in aerobic fitness are similar, regardless of the type of valve abnormality or whether CABG was performed concurrently.

Influence of glycemic control on gain in VO2 peak, in patients with type 2 diabetes enrolled in cardiac rehabilitation after an acute coronary syndrome. The prospective DARE study

Background

Gain in VO2 peak after cardiac rehabilitation (CR) following an acute coronary syndrome (ACS), is associated with reduced mortality and morbidity. We have previously shown in CR, that gain in VO2 peak is reduced in Type 2 diabetic patients and that response to CR is impaired by hyperglycemia.

Methods

We set up a prospective multicenter study (DARE) whose primary objective was to determine whether good glycemic control during CR may improve the gain in VO2 peak. Sixty four type 2 diabetic patients, referred to CR after a recent ACS, were randomized to insulin intensive therapy or a control group with continuation of the pre-CR antidiabetic treatment. The primary objective was to study the effect of glycemic control during CR on the improvement of peak VO2 by comparing first the 2 treatment groups (insulin intensive vs. control) and second, 2 pre-specified glycemic control groups according to the final fructosamine level (below and above the median).

Results

At the end of the CR program, the gain in VO2 peak and the final fructosamine level (assessing glycemic level during CR) were not different between the 2 treatment groups. However, patients who had final fructosamine level below the median value, assessing good glycemic control during CR, showed significantly higher gain in VO2 peak (3.5 ± 2.4 vs. 1.7 ± 2.4 ml/kg/min,p = 0.014) and ventilatory threshold (2.7 ± 2.5 vs. 1.2 ± 1.9 ml/kg/min,p = 0.04) and a higher proportion of good CR-responders (relative gain in VO2 peak ≥ 16 %): 66 % vs. 36 %, p = 0.011. In multivariate analysis, gain in VO2 peak was associated with final fructosamine level (p = 0.010) but not with age, gender, duration of diabetes, type of ACS, insulin treatment or basal fructosamine.

Conclusions

The DARE study shows that, in type 2 diabetes, good glycemic control during CR is an independent factor associated with gain in VO2 peak. This emphasizes the need for good glycemic control in CR for type 2 diabetic patients.

Trial registration

Trial registered as NCT00354237 (19 July 2006).

Cardiac rehabilitation is associated with lasting improvements in cognitive function in older adults with heart failure

OBJECTIVE

Heart failure (HF) is a known risk factor for cognitive impairment. Cardiac rehabilitation (CR) may attenuate poor neurocognitive outcomes in HF via improved physical fitness--a significant promoter of cognitive function. However, no study has examined the possible acute and lasting benefits of CR on cognitive function in persons with HF.

METHODS AND RESULTS

Fifty-two patients with HF completed a 12-week Phase II CR program. All participants were administered neuropsychological testing and completed a brief physical fitness assessment at baseline, completion of CR (i.e. 12 weeks), and 12-month follow-up. Repeated measures analyses showed a significant time effect for both attention/executive function and memory (P < 0.05). Attention/executive function performance increased from baseline to 12 weeks and these gains remained up to 12 months; memory was unchanged from baseline to 12 weeks, but then improved between the 12-week and 12-month time points. Physical fitness improved from baseline to 12 weeks and these benefits were maintained 12 months later. Changes in physical fitness and cognitive function over time did not reach a statistically significant association, though poorer physical fitness was associated with decreased cognitive performance at the baseline and 12-month time points.

CONCLUSIONS

CR is associated with both acute and lasting cognitive benefits in patients with HF. Prospective studies with extended follow-ups are needed to clarify the mechanisms that underpin cognitive improvements following CR (e.g., improved cerebral perfusion) and whether CR can ultimately reduce risk for cognitive decline and conditions like Alzheimer's disease in HF.

Benefits of exercise training and the correlation between aerobic capacity and functional outcomes and quality of life in elderly patients with coronary artery disease

Cardiopulmonary exercise training is beneficial to people with coronary artery disease (CAD). Nevertheless, the correlation between aerobic capacity, and functional mobility and quality of life in elderly CAD patients is less addressed. The purpose of the current study is to investigate the beneficial effects of exercise training in elderly people with CAD, integrating exercise stress testing, functional mobility, handgrip strength, and health-related quality of life. Elderly people with CAD were enrolled from the outpatient clinic of a cardiac rehabilitation unit in a medical center. Participants were assigned to the exercise training group (N = 21) or the usual care group (N = 15). A total of 36 sessions of exercise training, completed in 12 weeks, was prescribed. Echocardiography, exercise stress testing, the 6-minute walking test, Timed Up and Go test, and handgrip strength testing were performed, and the Short-Form 36 questionnaire (SF-36) was administered at baseline and at 12-week follow-up. Peak oxygen consumption improved significantly after training. The heart rate recovery improved from 13.90/minute to 16.62/minute after exercise training. Functional mobility and handgrip strength also improved after training. Significant improvements were found in SF-36 physical function, social function, role limitation due to emotional problems, and mental health domains. A significant correlation between dynamic cardiopulmonary exercise testing parameters, the 6-minute walking test, Timed Up and Go test, handgrip strength, and SF-36 physical function and general health domains was also detected. Twelve-week, 36-session exercise training, including moderate-intensity cardiopulmonary exercise training, strengthening exercise, and balance training, is beneficial to elderly patients with CAD, and cardiopulmonary exercise testing parameters correlate well with balance and quality of life.

Physiological and exercise capacity improvements in women completing cardiac rehabilitation

PURPOSE

The objective of this study was to examine the improvements in physiological outcomes, including exercise capacity, in women completing a 12-week gender-specific (tailored) compared with a traditional cardiac rehabilitation (CR) program.

METHODS

A 2-group randomized clinical trial compared symptom limited graded exercise test (SL-GXT), lipid, and anthropometric parameters among 99 women completing a traditional 12-week CR program with 137 women completing a tailored CR program.

RESULTS

Compared with baseline, improvement in estimated peak metabolic equivalents (METs) was similar (P = .159) between the tailored (6.0 ± 2.7-7.6 ± 2.8) and the traditional CR programs (5.6 ± 2.3-7.1 ± 2.8). The amount of change in SL-GXT, anthropometric parameters, lipid profiles, and peak treadmill time from baseline to post-CR were also similar between the 2 groups. Given comparable improvements of the 2 CR programs, in the full cohort, factors independently associated with post-CR METs, in rank order, included baseline METs (part correlation = 0.44, P < .001), perceived physical functioning (0.24, P < .001), waist circumference (-0.10, P = .006), and age (-0.11, P = .004). Factors independently associated with post-CR treadmill time included baseline treadmill time (part correlation = 0.42, P < .001), perceived physical functioning (0.30, P < .001), waist circumference (-0.12, P = .002), and age (-0.10, P 5.006).

CONCLUSIONS

Exercise capacity was significantly improved among women completing both CR programs. In the context of CR, modifiable factors positively associated with post-CR exercise capacity included reduced waist circumference and improved physical functioning. Future research on strategies for reducing abdominal obesity and improving perceived physical functioning and exercise capacity among women attending CR is warranted.

Effect of cardiac rehabilitation on muscle mass, muscle strength, and exercise tolerance in diabetic patients after coronary artery bypass grafting

BACKGROUND

The effects of cardiac rehabilitation (CR) on muscle mass, muscle strength, and exercise tolerance in patients with diabetes mellitus (DM) who received CR after coronary artery bypass grafting (CABG) have not been fully elucidated.

METHODS

We enrolled 78 consecutive patients who completed a supervised CR for 6 months after CABG (DM group, n=37; non-DM group, n=41). We measured mid-upper arm muscle area (MAMA), handgrip power (HGP), muscle strength of the knee extensor (Ext) and flexor (Flex), and exercise tolerance at the beginning and end of CR.

RESULTS

No significant differences in confounding factors, including age, gender, ejection fraction, or number of CR sessions, were observed between the two groups. At the beginning of CR, the levels of Ext muscle strength and peak VO2 were significantly lower in the DM group than in the non-DM group. At the end of CR, significant improvement in the levels of muscle strength, HGP, and exercise tolerance was observed in both groups. However, the levels of Ext muscle strength, HGP, peak VO2, thigh circumference, and MAMA were significantly lower in the DM group than in the non-DM group. In addition, no significant improvement in thigh circumference and MAMA was observed in the DM group. At the end of CR, the levels of thigh circumference and MAMA correlated with Ext and Flex muscle strength as well as with HGP. Percent changes in the levels of Ext muscle strength were significantly correlated with those of MAMA and hemoglobin A1c.

CONCLUSIONS

These data suggest that improvement in muscle strength may be influenced by changes in muscle mass and high glucose levels in DM patients undergoing CR after CABG. A CR program, including muscle mass intervention and blood glucose control, may improve deterioration in exercise tolerance in DM patients after CABG.

Impact of diabetes on muscle mass, muscle strength, and exercise tolerance in patients after coronary artery bypass grafting

BACKGROUND

The impact of diabetes mellitus (DM) on muscle mass, muscle strength, and exercise tolerance in patients who had undergone coronary artery bypass grafting (CABG) has not been fully elucidated.

METHODS

We enrolled 329 consecutive patients who received cardiac rehabilitation (CR) after CABG (DM group, n=178; non-DM group, n=151) and measured lean body weight, mid-upper arm muscle area (MAMA), and handgrip power (HGP) at the beginning of CR. We also performed an isokinetic strength test of the knee extensor (Ext) and flexor (Flex) muscles and a cardiopulmonary exercise testing at the same time.

RESULTS

No significant differences in risk factors, including age, gender, number of diseased vessels, or ejection fraction were observed between the 2 groups. The levels of Ext muscle strength, peak oxygen uptake, and anaerobic threshold were significantly lower in the DM group than in the non-DM group (all p<0.05). Both peak oxygen uptake and MAMA correlated with Ext and Flex muscle strength as well as HGP (all p<0.005). The MAMA, HGP, and Ext muscle strength were lower in patients who received insulin therapy than in those who did not. Interestingly, fasting glucose levels significantly and negatively correlated with Ext muscle strength.

CONCLUSIONS

These data suggest that DM patients had a lower muscle strength and exercise tolerance than non-DM patients. Moreover, a high glucose level may affect these deteriorations in DM patients after CABG.