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

Determinants of V̇+O2peak Changes After Aerobic Training in Coronary Heart Disease Patients

This study aimed to highlight the ventilatory and circulatory determinants of changes in ˙VO2peak after exercise-based cardiac rehabilitation (ECR) in patients with coronary heart disease (CHD). Eighty-two CHD patients performed, before and after a 3-month ECR, a cardiopulmonary exercise testing (CPET) on a bike with gas exchanges measurements (˙VO2peak, minute ventilation, i. e., ˙VE), and cardiac output (Q˙c). The arteriovenous difference in O2 (C(a-v¯)O2) and the alveolar capillary gradient in O2 (PAi-aO2) were calculated using Fick's laws. Oxygen uptake efficiency slope (OUES) was calculated. A 5.0% cut off was applied for differentiating non- (NR: ˙VO2<0.0%), low (LR: 0.0≤ ∆˙VO2<5.0%), moderate (MR: 5.0≤∆˙VO2 < 10.0%), and high responders (HR: ∆˙VO2≥10.0%) to ECR. A total of 44% of patients were HR (n=36), 20% MR (n=16), 23% LR (n=19), and 13% NR (n=11). For HR, the ˙VO2peak increase (p<0.01) was associated with increases in ˙VE (+12.8±13.0 L/min, p<0.01), (+1.0±0.9 L/min, p<0.01), and C(a-v¯)O2 (+2.3±2.5 mLO2/100 mL, p<0.01). MR patients were characterized by+6.7±19.7 L/min increase in ˙VE (p=0.04) and+0.7±1.0 L/min of Q˙c (p<0.01). ECR induced decreases in ˙VE (p=0.04) and C(a-v¯)O2 (p<0.01) and a Q˙c increase in LR and NR patients (p<0.01). Peripheral and ventilatory responses more than central adaptations could be responsible for the ˙VO2peak change with ECR in CHD patients.

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.

Cardiac Rehabilitation Using the Family-Centered Empowerment Model is Effective in Improving Long-term Mortality in Patients with Myocardial Infarction: A 10-year Follow-Up Randomized Clinical Trial

INTRODUCTION

Cardiac rehabilitation (CR) play a critical role in reducing the risk of future cardiovascular events and enhancing the quality of life for individuals who have survived a heart attack.

AIM

To assess the mortality rates and stability of the effects in myocardial infarction (MI) survivors after implementing a Family-Centered Empowerment Model (FCEM)-focused hybrid cardiac rehabilitation program.

METHODS

This double-blind randomized controlled clinical trial, conducted at Shariati Hospital, an academic teaching hospital in Tehran, Iran (2012-2023), involved 70 MI patients and their families. Participants were randomly assigned to an FCEM intervention group or standard CR control group. The intervention commenced after the MI patient's safe discharge from the CCU and continued for the entire 10-year follow-up period. Various questionnaires were utilized to collect data on mortality rates and health-related quality of life (HRQoL).

RESULTS

The 10-year follow-up period revealed lower mortality rates in the intervention group (5.7%, 11.4%, and 17.1% at 5, 7, and 10 years, respectively) compared to the control group (20%, 37.1%, and 48.9%). After adjusting for age, gender, and BMI, the control group had a four times higher mortality risk (HR: 4.346, 95% CI 1.671-7.307, P = 0.003). The FCEM-focused program demonstrated a significant and sustained positive impact on participants' quality of life for 48 months, with greater improvement compared to the control group.

CONCLUSION

This study highlights the effectiveness of FCEM-based hybrid CR programs in enhancing long-term patient outcomes and reducing mortality rates among MI survivors. Further research is needed to explore the potential benefits in larger samples and diverse populations.

TRIAL REGISTRATION

This study (Identifier: NCT02402582) was registered in the ClinicalTrials.gov on 03/30/2015.

An Index for Evaluating Exercise Capacity Improvement After Cardiac Rehabilitation in Patients After Myocardial Infarction

OBJECTIVE

We investigated relationships among predictors of improvement in exercise capacity after cardiac rehabilitation programs in patients after acute myocardial infarction.

METHODS

We carried out a secondary analysis of data from 41 patients with a left ventricular ejection fraction ≥ 40% who underwent cardiac rehabilitation after the first myocardial infarction. Participants were assessed using a cardiopulmonary exercise test and stress echocardiography. A cluster analysis was performed, and the principal components were analyzed.

RESULTS

Two distinct clusters with significantly different ( P = .005) proportions of response to treatment (peak VO 2 ≥ 1 mL/kg/min) were identified among patients. The first principal component explained 28.6% of the variance. We proposed an index composed of the top 5 variables from the first component to represent the improvement in exercise capacity. The index was the average of scaled O 2 uptake and CO 2 output at peak exercise, minute ventilation at peak, load achieved at peak exercise, and exercise time. The optimal cutoff for the improvement index was 0.12, which outperformed the peak VO 2 ≥ 1 mL/kg/min criterion in recognizing the clusters, with a C-statistic of 91.7% and 72.3%, respectively.

CONCLUSION

The assessment of change in exercise capacity after cardiac rehabilitation could be improved using the composite index.

Impact of training on combined cardiopulmonary exercise test with stress echocardiography parameters in HFrEF patients

BACKGROUND

Exercise-based cardiac rehabilitation is recognized to improve quality of life in heart failure patients. However, the effects on the cardiac function are understudied. The main objective was to assess the impact of a 4-week cardiac rehabilitation program on cardiopulmonary exercise testing (CPET) combined with simultaneous echocardiography parameters in chronic heart failure (CHF) patients. The secondary aim was to investigate patients' responses to training.

METHODS

Forty-one CHF patients with reduced ejection fraction (29.3 ± 0.1%) underwent CPET and stress echocardiography before and after a 4-week of exercise-training program. Blood parameters, echocardiography and cardiopulmonary parameters were assessed before and after training. Potential echocardiography derived predictive parameters like left and right contractile reserves, left ventricle elastance, end systolic volume and right ventricle S wave response to exercise were also assessed.

RESULTS

The training program increased the peak oxygen consumption (VO₂) (P < 0.001), the peak systolic blood pressure, the left ventricular outflow tract velocity time integral (P < 0.05) and the circulatory (P < 0.001) and ventilatory (P < 0.01) powers. It also decreased the VE/VCO₂ slope (P < 0.001). As the median value of peak VO₂ gain was 17%, patients above this value were considered as responders and patients below as non-responders to training. The responders presented a higher left ventricle contractile reserve compared to non-responder patients. The peak left ventricle elastance and peak right ventricle S wave response tended to be higher in responders.

CONCLUSION

Combination of CPET and stress echocardiography may contribute to establish the disease severity stratification and to predict response to training in CHF patients with reduced ejection fraction.

Serial Changes in Exercise Capacity, NT-proBNP, and Adiponectin in Patients with Acute Coronary Syndrome before and after Phase II Rehabilitation as well as at the 12-Month Follow-Up

Background. Acute coronary syndrome (ACS) causes pathophysiological changes in exercise capacity, N-terminal part of pro-brain natriuretic peptide (NT-proBNP), and adiponectin that impact the course of coronary artery disease and clinical outcomes after cardiac rehabilitation (CR). However, the serial changes and the relationship between the changes in these parameters for a prolonged term remain uninvestigated. Methods. Eighty-one patients with ACS underwent a three- or four-week CR program after acute care and were followed up for 12 months. Exercise capacity on a cycle ergometer and blood levels of NT-proBNP and adiponectin were determined before and after CR as well as at the 12-month follow-up. Results. Exercise capacity increased from 100 watts (in median) before CR to 138 watts after CR and 150 watts at 12 months. The NT-proBNP level (526 pg/ml before CR) remained almost unchanged after CR (557 pg/ml) and then decreased at 12 months (173 pg/ml). The adiponectin level (14.5 µg/ml before CR) increased after CR (16.0 µg/ml) and at 12 months (17.2 µg/ml). There was no significant correlation among the changes in these parameters at each observation time point. Conclusion. During the observation period from before CR to the 12-month follow-up, exercise capacity, NT-proBNP, and adiponectin underwent significant changes; however, these changes were independent from each other and not correlated linearly, and they provide complementary information in clinical practice. Thus, all these parameters should be included and determined at different time points for a prolonged period of time.