Relationship between exercise tolerance and muscle strength following cardiac rehabilitation: Comparison of patients after cardiac surgery and patients with myocardial infarction

Investigation of Skeletal Muscle Indices Affecting Anaerobic Thresholds after Acute Myocardial Infarction

OBJECTIVE

To investigate skeletal muscle indices influencing the anaerobic threshold (AT) measured by cardiopulmonary exercise testing (CPX).

METHODS

This study included 125 consecutive men (median age: 66.0 years) diagnosed with acute myocardial infarction who underwent CPX before discharge. Participants were categorized into two groups based on their AT: the AT-lowering and AT-maintaining groups, comprising those with AT <11 and ≥11 ml/min/kg, respectively. Skeletal muscle indices that influenced AT, strengths of such influences, and respective cutoff values were investigated using multiple logistic regression analysis, decision-tree analysis, and the random-forest method. Skeletal muscle indices included grip strength, knee extension strength, lower-limb skeletal muscle index, phase angle (PhA), lower-limb PhA, arm circumference (AC), and calf circumference.

RESULTS

Lower-limb PhA, AC, age, and body mass index (BMI) influenced AT (model X2 test: p <0.05; Hosmer-Lemeshow test: p = 0.98). Among the skeletal muscle indices, Gini impurity reduction was the highest in the lower-limb PhA. The cutoff values for AT were ≥4.0° for BMI <24 kg/m2 and ≥6.4° for BMI ≥24 kg/m2.

CONCLUSION

Lower-limb PhA was the most influential skeletal muscle index affecting AT. PhA measured using body composition analyzers is useful to identify exercise-limiting factors and determine the effectiveness of exercise because it can be easily performed shortly.

Cardiorespiratory Fitness Benefits of Long-Term Maintenance-Phase Cardiac Rehabilitation in Males and Females: A Retrospective Cohort Study

Purpose

This study investigated if associations exist between enrolment delay and VO2peak over five years of maintenance-phase cardiac rehabilitation (CR) in males and females.

Method

Data were extracted from the records of participants who had enrolled for ≥ 1 year in CR and completed ≥ 2 cardiopulmonary exercise tests. Mixed model analyses examined VO2peak trajectories for up to five years of enrolment. Interactions between enrolment delay × enrolment duration, baseline age × enrolment duration, and baseline VO2peak × enrolment duration were explored for inclusion in the model.

Results

The charts of 151 males (aged 63.9 ± 9.4 y) and 32 females (aged 65.3 ± 9.0 y) were included in the analyses. The enrolment delay following a cardiovascular event was 1.8 ± 3.0 years for males and 1.3 ± 1.7 years for females. No associations were found between enrolment delay × enrolment duration on VO2peak in males (β[SEj, 0.07[0.05]; 95% CI -0.02, 0.16, p = 0.12) or in females (β[SE], 0.07[0.13j; 95% CI -0.18, 0.33, p = 0.57), but predicted trajectories suggest clinically significantly improvements in VO2 peak (range, 1.3 to 1.6 mL/kg/min).

Conclusions

Early enrolment in CR is recommended and encouraged, but the benefits of long-term CR are possible despite delays.

Brown adipose tissue prevents glucose intolerance and cardiac remodeling in high-fat-fed mice after a mild myocardial infarction

BACKGROUND

Obesity increases the risk of developing impaired glucose tolerance (IGT) and type 2 diabetes (T2D) after myocardial infarction (MI). Brown adipose tissue (BAT) is important to combat obesity and T2D, and increasing BAT mass by transplantation improves glucose metabolism and cardiac function. The objective of this study was to determine if BAT had a protective effect on glucose tolerance and cardiac function in high-fat diet (HFD) fed mice subjected to a mild MI.

METHODS

Male C57BL/6 mice were fed a HFD for eight weeks and then divided into Sham (Sham-operated) and +BAT (mice receiving 0.1 g BAT into their visceral cavity). Sixteen weeks post-transplantation, mice were further subdivided into ±MI (Sham; Sham-MI; +BAT; +BAT-MI) and maintained on a HFD. Cardiac (echocardiography) and metabolic function (glucose and insulin tolerance tests, body composition and exercise tolerance) were assessed throughout 22 weeks post-MI. Quantitative PCR (qPCR) was performed to determine the expression of genes related to metabolic function of perigonadal adipose tissue (pgWAT), subcutaneous white adipose tissue (scWAT), liver, heart, tibialis anterior skeletal muscle (TA); and BAT.

RESULTS

+BAT prevented the increase in left ventricle mass (LVM) and exercise intolerance in response to MI. Similar to what is observed in humans, Sham-MI mice developed IGT post-MI, but this was negated in +BAT-MI mice. IGT was independent of changes in body composition. Genes involved in inflammation, insulin resistance, and metabolism were significantly altered in pgWAT, scWAT, and liver in Sham-MI mice compared to all other groups.

CONCLUSIONS

BAT transplantation prevents IGT, the increase in LVM, and exercise intolerance following MI. MI alters the expression of several metabolic-related genes in WAT and liver in Sham-MI mice, suggesting that these tissues may contribute to the impaired metabolic response. Increasing BAT may be an important intervention to prevent the development of IGT or T2D and cardiac remodeling in obese patients post-MI.

Long-Term Enrollment in Cardiac Rehabilitation Benefits of Cardiorespiratory Fitness and Skeletal Muscle Strength in Females with Cardiovascular Disease

Background: The benefits of short-term cardiac rehabilitation (CR) for improving fitness are well known, but the effects of long-term maintenance-phase CR are less well established. Moreover, changes in cardiorespiratory fitness (CRF) and muscle strength with long-term CR have never been examined specifically in females, a population that is under-researched and under-represented in cardiovascular research. The objective of this retrospective pilot study was to estimate changes in CRF and muscle strength in females enrolled in a long-term CR program. Methods: Data from 39 females (mean ± standard deviation age 65 ± 9 years) enrolled for at least 1 year in a maintenance-phase CR program were analyzed. The program consisted of aerobic and resistance training, and data were collected annually for CRF (peak oxygen consumption [VO₂peak, mL/kg/min]) and skeletal muscle strength (one-repetition maximum tests for chest press, seated row, and knee extension, kg). Mixed-model analyses were used to determine changes in CRF over the 5-year follow-up (203 observations) and muscle strength over 6 years (108 observations). Results: The CRF increased in females by 1.8%/year over 5 years of CR enrollment, and muscle strength increased by 0.6%-2.1%/year over 6 years. These findings are in contrast to the expected age-related declines in fitness over time. Conclusion: The positive long-term benefits on CRF and muscle strength in females provide initial preliminary support for maintenance-based CR, especially given that this population is commonly under-researched and under-represented in the CR literature.

Is the Clinical Delivery of Cardiac Rehabilitation in an Australian Setting Associated with Changes in Physical Capacity and Cardiovascular Risk and Are Any Changes Maintained for 12 Months?

Long-term maintenance of changes in cardiovascular risk factors and physical capacity once patients leave the supervised program environment have not previously been reported. This study investigated the changes in physical capacity outcomes and cardiovascular risk factors in an Australian cardiac rehabilitation setting, and the maintenance of changes in these outcomes in the 12 months following cardiac rehabilitation attendance. Improvements in mean (95% CI) cardiorespiratory fitness (16.4% (13.2–19.6%), p < 0.001) and handgrip strength (8.0% (5.4–10.6%), p < 0.001) were observed over the course of the cardiac rehabilitation program, and these improvements were maintained in the 12 months following completion. Waist circumference (p = 0.003) and high-density lipoprotein cholesterol (p < 0.001) were the only traditional cardiovascular risk factors to improve during the cardiac rehabilitation program. Vigorous-intensity aerobic exercise was associated with significantly greater improvements in cardiorespiratory fitness, Framingham risk score, and waist circumference in comparison to moderate-intensity exercise. An increase in the intensity of the exercise prescribed during cardiac rehabilitation in Australia is recommended to induce larger improvements in physical capacity outcomes and cardiovascular risk. A standardized exercise test at the beginning of the rehabilitation program is recommended to facilitate appropriate prescription of exercise intensity.

Exercise-based cardiac rehabilitation for adults after heart valve surgery

BACKGROUND

The impact of exercise-based cardiac rehabilitation (CR) following heart valve surgery is uncertain. We conducted an update of this systematic review and a meta-analysis to assess randomised controlled trial evidence for the use of exercise-based CR following heart valve surgery.

OBJECTIVES

To assess the benefits and harms of exercise-based CR compared with no exercise training in adults following heart valve surgery or repair, including both percutaneous and surgical procedures. We considered CR programmes consisting of exercise training with or without another intervention (such as an intervention with a psycho-educational component).

SEARCH METHODS

We searched the Cochrane Central Register of Clinical Trials (CENTRAL), in the Cochrane Library; MEDLINE (Ovid); Embase (Ovid); the Cumulative Index to Nursing and Allied Health Literature (CINAHL; EBSCO); PsycINFO (Ovid); Latin American Caribbean Health Sciences Literature (LILACS; Bireme); and Conference Proceedings Citation Index-Science (CPCI-S) on the Web of Science (Clarivate Analytics) on 10 January 2020. We searched for ongoing trials from ClinicalTrials.gov, Clinical-trials.com, and the World Health Organization International Clinical Trials Registry Platform on 15 May 2020.

SELECTION CRITERIA

We included randomised controlled trials that compared exercise-based CR interventions with no exercise training. Trial participants comprised adults aged 18 years or older who had undergone heart valve surgery for heart valve disease (from any cause) and had received heart valve replacement or heart valve repair. Both percutaneous and surgical procedures were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. We assessed the risk of systematic errors ('bias') by evaluating risk domains using the 'Risk of bias' (RoB2) tool. We assessed clinical and statistical heterogeneity. We performed meta-analyses using both fixed-effect and random-effects models. We used the GRADE approach to assess the quality of evidence for primary outcomes (all-cause mortality, all-cause hospitalisation, and health-related quality of life).

MAIN RESULTS

We included six trials with a total of 364 participants who have had open or percutaneous heart valve surgery. For this updated review, we identified four additional trials (216 participants). One trial had an overall low risk of bias, and we classified the remaining five trials as having some concerns. Follow-up ranged across included trials from 3 to 24 months. Based on data at longest follow-up, a total of nine participants died: 4 CR versus 5 control (relative risk (RR) 0.83, 95% confidence interval (CI) 0.26 to 2.68; 2 trials, 131 participants; GRADE quality of evidence very low). No trials reported on cardiovascular mortality. One trial reported one cardiac-related hospitalisation in the CR group and none in the control group (RR 2.72, 95% CI 0.11 to 65.56; 1 trial, 122 participants; GRADE quality of evidence very low). We are uncertain about health-related quality of life at completion of the intervention in CR compared to control (Short Form (SF)-12/36 mental component: mean difference (MD) 1.28, 95% CI -1.60 to 4.16; 2 trials, 150 participants; GRADE quality of evidence very low; and SF-12/36 physical component: MD 2.99, 95% CI -5.24 to 11.21; 2 trials, 150 participants; GRADE quality of evidence very low), or at longest follow-up (SF-12/36 mental component: MD -1.45, 95% CI -4.70 to 1.80; 2 trials, 139 participants; GRADE quality of evidence very low; and SF-12/36 physical component: MD -0.87, 95% CI -3.57 to 1.83; 2 trials, 139 participants; GRADE quality of evidence very low).  AUTHORS' CONCLUSIONS: Due to lack of evidence and the very low quality of available evidence, this updated review is uncertain about the impact of exercise-CR in this population in terms of mortality, hospitalisation, and health-related quality of life. High-quality (low risk of bias) evidence on the impact of CR is needed to inform clinical guidelines and routine practice.

Improvements in exercise tolerance with an exercise intensity above the anaerobic threshold in patients with acute myocardial infarction

Anaerobic threshold (AT) from cardiopulmonary exercise tests (CPX) is the standard for measuring exercise intensity among patients with cardiovascular disease in Japan. However, it remains controversial whether AT represents the safety limit for exercise intensity in patients with cardiovascular disease. The purpose of this study was to investigate cardiac rehabilitation (CR) efficacy and safety with exercise intensities above the AT and at a traditional AT in a randomized trial. The participants included 57 patients who were admitted to the outpatient CR unit with a diagnosis of acute myocardial infarction. The participants were randomly divided as follows: 25 patients in the AT group, who performed aerobic exercises with an intensity at the AT; and 32 patients in the "Over AT" group, who performed exercises at an intensity higher than the AT. The following components were measured: maximum oxygen uptake (peak VO₂), oxygen uptake at the AT (AT VO₂), increase in oxygen uptake during exercise (ΔVO₂/ΔWR) during the CPX, vascular endothelial function test (%FMD: the percentage of flow-mediated dilation), and isometric knee extension strength. The measurements were obtained at the start of the exercise therapy and after 2, 3, and 4 months. They were compared within and between groups, and the correlation between the rates of improvement was investigated. Peak VO₂, AT VO₂, ΔVO₂/ΔWR, and %FMD had significantly improved after 3 months in both groups. The isometric knee extension strength had improved in the "Over AT" group after 2 months. Interactions were observed with peak VO₂, ΔVO₂/ΔWR, and isometric knee extension strength. However, %FMD was not significantly different between the groups. In the "Over AT" group, the rate of improvement in peak VO₂ was positively correlated with the improvement in the isometric knee extension strength (r = 0.61, p < 0.001), but not with %FMD. These data suggest that exercise at an intensity above the AT improved exercise tolerance faster than that at the AT, and this improvement rate was associated with changes in isometric knee extension strength.

Is Physical Therapy the Early Solution for Post-Acute Myocardial Infarction Patients? A Meta-Analysis

Background: Physical rehabilitation is essential to improve the quality of life of patients with acute myocardial infarction (AMI).

Study aim: The study intended to demonstrate the benefits of early rehabilitation in patients with AMI.

Material and method: We performed a meta-analysis to document the benefits of physical treatment in patients who suffered an AMI. Studies were searched in the following databases: PubMed, PlosOne, Mendeley, and clinicaltrials.gov. The terms used in our research were “rehabilitation”, “physical exercise”, “physical training” “quality of life”, “early”, and “post MI”. The inclusion criteria consisted in the assessment of the following parameters: heart rate, maximal/submaximal capacity, and characteristics of the left ventricle – end-diastolic volume, ejection fraction, and left ventricle hypertrophy included in the study design.

Results: The database search identified 710 studies, of which only 10 passed the inclusion criteria. Out of 1,515 patients who underwent early physical therapy, 960 reported improvement in the quality of their life (p <0.001). A number of 2,703 patients out of a total of 3,595 underwent a complete physical treatment and medication program. From the ten studies included in the meta-analysis, six had a positive feedback to the multimodal treatment within 1 month post-AMI. Patients who performed physical exercises within a month after the cardiac arrest (1,103 post-AMI patients from a total of 1,278) demonstrated a high heterogeneity represented by the coefficient I2 = 84% but with a significant statistical value of p <0.00001.

Conclusion: Early physical therapy initiation significantly improves the quality of life of patients with AMI.

Does CABG with Saphenous Vein Grafting and Standard Cardiac Rehabilitation Affect Lower Limb Function? A Clinical Study

BACKGROUND

The aim of the study was to assess lower limb function in response to two cardiac rehabilitation (CR) protocols after coronary artery bypass surgery with saphenous vein grafting.

METHODS

Clinically-stable male patients aged 50-70 years were recruited 4 weeks post-surgery in which to group. Group I (n = 47) receive standard CR in a hospital setting for 3 weeks and Group II (n = 14) receive CR with a resistance training component in an outpatient setting for 8 weeks. Measures included body mass and composition, lower limb temperature distribution, lower limb hemodynamics, and dorsal and plantar flexor muscle strength.

RESULTS

Average temperature of the operated limb decreased only in Group II after cardiac rehabilitation. Venous blood flow improved in both groups as evidenced by increased blood refilling time. Isokinetic strength was greater in Group I.

CONCLUSIONS

The results suggest a 3-week intensive CR protocol to be most effective in restoring lower limb function in CABG patients after saphenectomy.

Is Exercise Prescription in Cardiac Rehabilitation Influenced by Physical Capacity or Cardiac Intervention?

This study investigated the influence of cardiac intervention and physical capacity of individuals attending an Australian outpatient cardiac rehabilitation program on the initial exercise prescription. A total of 85 patients commencing outpatient cardiac rehabilitation at a major metropolitan hospital had their physical capacity assessed by an incremental shuttle walk test, and the initial aerobic exercise intensity and resistance training load prescribed were recorded. Physical capacity was lower in surgical patients than nonsurgical patients. While physical capacity was higher in younger compared with older surgical patients, there was no difference between younger and older nonsurgical patients. The initial exercise intensity did not differ between surgical and nonsurgical patients. This study highlights the importance of preprogram exercise testing to enable exercise prescription to be individualized according to actual physical capacity, rather than symptoms, comorbidities and age, in order to maximize the benefit of cardiac rehabilitation.

Home-Based Rehabilitation With Telemonitoring Guidance for Patients With Coronary Artery Disease (Short-Term Results of the TRiCH Study): Randomized Controlled Trial

Background

Cardiac rehabilitation (CR) is an essential part of contemporary coronary heart disease management. However, patients exiting a center-based CR program have difficulty retaining its benefits.

Objective

We aimed to evaluate the added benefit of a home-based CR program with telemonitoring guidance on physical fitness in patients with coronary artery disease (CAD) completing a phase II ambulatory CR program and to compare the effectiveness of this program in a prolonged center-based CR intervention by means of a randomized controlled trial.

Methods

Between February 2014 and August 2016, 90 CAD patients (unblinded, mean age 61.2 years, SD 7.6; 80/90, 89.0% males; mean height 1.73 m, SD 0.7; mean weight 82.9 kg, SD 13; mean body mass index 27.5 kg/m², SD 3.4) who successfully completed a 3-month ambulatory CR program were randomly allocated to one of three groups: home-based (30), center-based (30), or control group (30) on a 1:1:1 basis. Home-based patients received a home-based exercise intervention with telemonitoring guidance consisting of weekly emails or phone calls; center-based patients continued the standard in-hospital CR, and control group patients received the usual care including the advice to remain physically active. All the patients underwent cardiopulmonary exercise testing for assessment of their peak oxygen uptake (VO₂ P) at baseline and after a 12-week intervention period. Secondary outcomes included physical activity behavior, anthropometric characteristics, traditional cardiovascular risk factors, and quality of life.

Results

Following 12 weeks of intervention, the increase in VO₂ P was larger in the center-based (P=.03) and home-based (P=.04) groups than in the control group. In addition, oxygen uptake at the first (P-interaction=.03) and second (P-interaction=.03) ventilatory thresholds increased significantly more in the home-based group than in the center-based group. No significant changes were observed in the secondary outcomes.

Conclusions

Adding a home-based exercise program with telemonitoring guidance following completion of a phase II ambulatory CR program results in further improvement of physical fitness and is equally as effective as prolonging a center-based CR in patients with CAD.

Trial Registration

ClinicalTrials.gov NCT02047942; https://clinicaltrials.gov/ct2/show/NCT02047942 (Archived by WebCite at http://www.webcitation.org/70CBkSURj)

Multimedia Exercise Training Program Improves Distance Walked, Heart Rate Recovery, and Self-efficacy in Cardiac Surgery Patients

BACKGROUND

Patient education has been shown to be more effective when delivered using multimedia than written materials. However, the effects of using multimedia to assist patients in cardiac rehabilitation have not been investigated.

OBJECTIVE

The purpose of this study is to examine the effect of an inpatient multimedia exercise training program on distance walked in the 6-minute walking test (6MWT), heart rate recovery, and walking self-efficacy of patients who had undergone heart surgery.

METHODS

For this longitudinal quasi-experimental study, 60 consecutive patients were assigned to an experimental (n = 20; inpatient multimedia exercise training program) or control (n = 40; routine care) group. Data were collected at 3 times (before surgery, 1 to 2 days before hospital discharge, and 1 month after hospital discharge) and analyzed with the generalized estimating equation approach.

RESULTS

Most subjects were men (66.7%), had a mean age of 61.32 ± 13.4 years and left ventricular ejection fraction of 56.96% ± 13.28%, and underwent coronary artery bypass graft surgery (n = 34, 56.7%). Subjects receiving the exercise training program showed significantly greater improvement than those in the control group in the 6MWT walking distance (P < .001), heart rate recovery (P = .04), and self-efficacy (P = .002) at hospital discharge. Furthermore, the intervention effects on 6MWT distance (P < .001) and self-efficacy (P < .001) were sustained at 1 month after hospital discharge.

CONCLUSION

Our inpatient multimedia exercise training program safely improved distance walked in the 6MWT, heart rate recovery, and self-efficacy at hospital discharge in patients after heart surgery and maintained their improvement in 6MWT and self-efficacy 1 month later.

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.

Inpatient cardiac rehabilitation programs' exercise therapy for patients undergoing cardiac surgery: National Korean Questionnaire Survey

Inpatient cardiac rehabilitation (ICR) has been commonly conducted after cardiac surgery in many countries, and has been reported a lots of results. However, until now, there is inadequacy of data on the status of ICR in Korea. This study described the current status of exercise therapy in ICR that is performed after cardiac surgery in Korean hospitals. Questionnaires modified by previous studies were sent to the departments of thoracic surgery of 10 hospitals in Korea. Nine replies (response rate 90%) were received. Eight nurses and one physiotherapist completed the questionnaire. Most of the education on wards after cardiac surgery was conducted by nurses. On postoperative day 1, four sites performed sitting on the edge of bed, sit to stand, up to chair, and walking in the ward. Only one site performed that exercise on postoperative day 2. One activity (stairs up and down) was performed on different days at only two sites. Patients received education preoperatively and predischarge for preventing complications and reducing muscle weakness through physical inactivity. The results of the study demonstrate that there are small variations in the general care provided by nurses after cardiac surgery. Based on the results of this research, we recommended that exercise therapy programs have to conduct by exercise specialists like exercise physiologists or physiotherapists for patients in hospitalization period.

Exercise-based cardiac rehabilitation for adults after heart valve surgery

BACKGROUND

Exercise-based cardiac rehabilitation may benefit heart valve surgery patients. We conducted a systematic review to assess the evidence for the use of exercise-based intervention programmes following heart valve surgery.

OBJECTIVES

To assess the benefits and harms of exercise-based cardiac rehabilitation compared with no exercise training intervention, or treatment as usual, in adults following heart valve surgery. We considered programmes including exercise training with or without another intervention (such as a psycho-educational component).

SEARCH METHODS

We searched: the Cochrane Central Register of Controlled Trials (CENTRAL); the Database of Abstracts of Reviews of Effects (DARE); MEDLINE (Ovid); EMBASE (Ovid); CINAHL (EBSCO); PsycINFO (Ovid); LILACS (Bireme); and Conference Proceedings Citation Index-S (CPCI-S) on Web of Science (Thomson Reuters) on 23 March 2015. We handsearched Web of Science, bibliographies of systematic reviews and trial registers (ClinicalTrials.gov, Controlled-trials.com, and The World Health Organization International Clinical Trials Registry Platform).

SELECTION CRITERIA

We included randomised clinical trials that investigated exercise-based interventions compared with no exercise intervention control. The trial participants comprised adults aged 18 years or older who had undergone heart valve surgery for heart valve disease (from any cause) and received either heart valve replacement, or heart valve repair.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. We assessed the risk of systematic errors ('bias') by evaluation of bias risk domains. Clinical and statistical heterogeneity were assessed. Meta-analyses were undertaken using both fixed-effect and random-effects models. We used the GRADE approach to assess the quality of evidence. We sought to assess the risk of random errors with trial sequential analysis.

MAIN RESULTS

We included two trials from 1987 and 2004 with a total 148 participants who have had heart valve surgery. Both trials had a high risk of bias.There was insufficient evidence at 3 to 6 months follow-up to judge the effect of exercise-based cardiac rehabilitation compared to no exercise on mortality (RR 4.46 (95% confidence interval (CI) 0.22 to 90.78); participants = 104; studies = 1; quality of evidence: very low) and on serious adverse events (RR 1.15 (95% CI 0.37 to 3.62); participants = 148; studies = 2; quality of evidence: very low). Included trials did not report on health-related quality of life (HRQoL), and the secondary outcomes of New York Heart Association class, left ventricular ejection fraction and cost. We did find that, compared with control (no exercise), exercise-based rehabilitation may increase exercise capacity (SMD -0.47, 95% CI -0.81 to -0.13; participants = 140; studies = 2, quality of evidence: moderate). There was insufficient evidence at 12 months follow-up for the return to work outcome (RR 0.55 (95% CI 0.19 to 1.56); participants = 44; studies = 1; quality of evidence: low). Due to limited information, trial sequential analysis could not be performed as planned.

AUTHORS' CONCLUSIONS

Our findings suggest that exercise-based rehabilitation for adults after heart valve surgery, compared with no exercise, may improve exercise capacity. Due to a lack of evidence, we cannot evaluate the impact on other outcomes. Further high-quality randomised clinical trials are needed in order to assess the impact of exercise-based rehabilitation on patient-relevant outcomes, including mortality and quality of life.

Short-term inspiratory muscle training potentiates the benefits of aerobic and resistance training in patients undergoing CABG in phase II cardiac rehabilitation program

OBJECTIVE

To investigate the efficiency of short-term inspiratory muscle training program associated with combined aerobic and resistance exercise on respiratory muscle strength, functional capacity and quality of life in patients who underwent coronary artery bypass and are in the phase II cardiac rehabilitation program.

METHODS

A prospective, quasi-experimental study with 24 patients who underwent coronary artery bypass and were randomly assigned to two groups in the Phase II cardiac rehabilitation program: inspiratory muscle training program associated with combined training (aerobic and resistance) group (GCR + IMT, n=12) and combined training with respiratory exercises group (GCR, n=12), over a period of 12 weeks, with two sessions per week. Before and after intervention, the following measurements were obtained: maximal inspiratory and expiratory pressures (PImax and PEmax), peak oxygen consumption (peak VO2) and quality of life scores. Data were compared between pre- and post-intervention at baseline and the variation between the pre- and post-phase II cardiac rehabilitation program using the Student's t-test, except the categorical variables, which were compared using the Chi-square test. Values of P<0.05 were considered statistically significant.

RESULTS

Compared to GCR, the GCR + IMT group showed larger increments in PImax (P<0.001), PEmax (P<0.001), peak VO2 (P<0.001) and quality of life scores (P<0.001).

CONCLUSION

The present study demonstrated that the addition of inspiratory muscle training, even when applied for a short period, may potentiate the effects of combined aerobic and resistance training, becoming a simple and inexpensive strategy for patients who underwent coronary artery bypass and are in phase II cardiac rehabilitation.

Robot-Assisted Training Early After Cardiac Surgery

BACKGROUND

To assess feasibility and safety of a robot-assisted gait therapy with the Lokomat® system in patients early after open heart surgery.

METHODS

Within days after open heart surgery 10 patients were subjected to postoperative Lokomat® training (Intervention group, IG) whereas 20 patients served as controls undergoing standard postoperative physiotherapy (Control group, CG). All patients underwent six-minute walk test and evaluation of the muscular strength of the lower limbs by measuring quadriceps peak force. The primary safety end-point was freedom from any device-related wound healing disturbance. Patients underwent clinical follow-up after one month.

RESULTS

Both training methods resulted in an improvement of walking distance (IG [median, interquartile range, p-value]: +119 m, 70-201 m, p = 0.005; CG: 105 m, 57-152.5m, p < 0.001) and quadriceps peak force (IG left: +5 N, 3.8 7 N, p = 0.005; IG right: +3.5 N, 1.5-8.8 N, p = 0.011; CG left: +5.5 N, 4-9 N, p < 0.001; CG right: +6 N, 4.3-9.8 N, p < 0.001) in all participants. Results with robot-assisted training were comparable to early postoperative standard in hospital training (median changes in walking distance in percent, p = 0.81; median changes in quadriceps peak force in percent, left: p = 0.97, right p = 0.61). No deep sternal wound infection or any adverse event occurred in the robot-assisted training group.

CONCLUSIONS

Robot-assisted gait therapy with the Lokomat® system is feasible and safe in patients early after median sternotomy. Results with robot-assisted training were comparable to standard in hospital training. An adapted and combined aerobic and resistance training intervention with augmented feedback may result in benefits in walking distance and lower limb muscle strength (ClinicalTrials.gov number, NCT 02146196).

Morning and evening exercise

A growing body of evidence suggests that exercise may contribute to preventing pathological changes, treating multiple chronic diseases, and reducing mortality and morbidity ratios. Scientific evidence moreover shows that exercise plays a key role in improving health-related physical fitness components and hormone function. Regular exercise training is one of the few strategies that has been strictly adapted in healthy individuals and in athletes. However, time-dependent exercise has different outcomes, based on the exercise type, duration, and hormone adaptation. In the present review, we therefore briefly describe the type, duration, and adaptation of exercise performed in the morning and evening. In addition, we discuss the clinical considerations and indications for exercise training.

Effects of community-based cardiac rehabilitation on body composition and physical function in individuals with stable coronary artery disease: 1.6-year followup

Objective. To examine long-term changes in physical function and body composition in coronary artery disease (CAD) patients participating in ongoing community-based cardiac rehabilitation (CR). Design. Thirty-four individuals (69.7 ± 8.2 years; 79% men) participated in this longitudinal observational study. Baseline and follow-up assessments included incremental shuttle walk, short physical performance battery, handgrip strength, chair stands, body composition, last year physical activity, and CR attendance. Results. Participants attended 38.5 ± 30.3% sessions during 1.6 ± 0.2 year followup. A significant increase in 30-second chair stands (17.0 ± 4.7 to 19.6 ± 6.4, P < 0.001), body weight (75.8 ± 11.1 to 77.2 ± 12.1 kg, P = 0.001), and body fat (27.0 ± 9.5 to 29.1 ± 9.6%, P < 0.001) and a decline in handgrip strength (36.4 ± 9.4 to 33.0 ± 10.6 kg·f, P < 0.001) and muscle mass (40.8 ± 5.6 to 39.3 ± 5.8%, P < 0.001) were observed during followup. There was no significant change in shuttle walk duration. CR attendance was not correlated to observed changes. Conclusions. Elderly CAD patients participating in a maintenance CR program improve lower-body muscle strength but experience a decline in handgrip strength and unfavourable changes in body composition, irrespective of CR attendance.

Effect of comprehensive cardiac rehabilitation after heart valve surgery (CopenHeartVR): study protocol for a randomised clinical trial

Background

Heart valve diseases are common with an estimated prevalence of 2.5% in the Western world. The number is rising due to an ageing population. Once symptomatic, heart valve diseases are potentially lethal, and heavily influence daily living and quality of life. Surgical treatment, either valve replacement or repair, remains the treatment of choice. However, post surgery, the transition to daily living may become a physical, mental and social challenge. We hypothesise that a comprehensive cardiac rehabilitation programme can improve physical capacity and self-assessed mental health and reduce hospitalisation and healthcare costs after heart valve surgery.

Methods

A randomised clinical trial, CopenHeart_VR, aims to investigate whether cardiac rehabilitation in addition to usual care is superior to treatment as usual after heart valve surgery. The trial will randomly allocate 210 patients, 1:1 intervention to control group, using central randomisation, and blinded outcome assessment and statistical analyses. The intervention consists of 12 weeks of physical exercise, and a psycho-educational intervention comprising five consultations. Primary outcome is peak oxygen uptake (VO₂ peak) measured by cardiopulmonary exercise testing with ventilatory gas analysis. Secondary outcome is self-assessed mental health measured by the standardised questionnaire Short Form 36. Also, long-term healthcare utilisation and mortality as well as biochemistry, echocardiography and cost-benefit will be assessed. A mixed-method design is used to evaluate qualitative and quantitative findings encompassing a survey-based study before the trial and a qualitative pre- and post-intervention study.

Discussion

The study is approved by the local regional Research Ethics Committee (H-1-2011-157), and the Danish Data Protection Agency (j.nr. 2007-58-0015).

Trial registration

ClinicalTrials.gov (http://NCT01558765).

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.

Reliability and validity of the ultrasound technique to measure the rectus femoris muscle diameter in older CAD-patients

BACKGROUND

The increasing age of coronary artery disease (CAD) patients and the occurrence of sarcopenia in the elderly population accompanied by 'fear of moving' and hospitalization in these patients often results in a substantial loss of skeletal muscle mass and muscle strength. Cardiac rehabilitation can improve exercise tolerance and muscle strength in CAD patients but less data describe eventual morphological muscular changes possibly by more difficult access to imaging techniques. Therefore the aim of this study is to assess and quantify the reliability and validity of an easy applicable method, the ultrasound (US) technique, to measure the diameter of rectus femoris muscle in comparison to the muscle dimensions measured with CT scans.

METHODS

45 older CAD patients without cardiac event during the last 9 months were included in this study. 25 patients were tested twice with ultrasound with a two day interval to assess test-retest reliability and 20 patients were tested twice (once with US and once with CT) on the same day to assess the validity of the US technique compared to CT as the gold standard. Isometric and isokinetic muscle testing was performed to test potential zero-order correlations between muscle diameter, muscle volume and muscle force.

RESULTS

An intraclass correlation coefficient (ICC) of 0.97 ((95%CL: 0.92 - 0.99) was found for the test-retest reliability of US and the ICC computed between US and CT was 0.92 (95%CL: 0.81 - 0.97). The absolute difference between both techniques was 0.01 ± 0.12 cm (p = 0.66) resulting in a typical percentage error of 4.4%. Significant zero-order correlations were found between local muscle volume and muscle diameter assessed with CT (r = 0.67, p = 0.001) and assessed with US (r = 0.49, p < 0.05). Muscle strength parameters were also significantly correlated with muscle diameter assessed with both techniques (range r = 0.45-r = 0.61, p < 0.05).

CONCLUSIONS

Ultrasound imaging can be used as a valid and reliable measurement tool to assess the rectus femoris muscle diameter in older CAD patients.

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.