Effect of exercise training on left ventricular mechanics after acute myocardial infarction-an exploratory study

Influence of Physical Training after a Myocardial Infarction on Left Ventricular Contraction Mechanics

BACKGROUND

Exercise plays a positive role in the course of the ischemic heart disease, enhancing functional capacity and preventing ventricular remodeling.

OBJECTIVE

To investigate the impact of exercise on left ventricular (LV) contraction mechanics after an uncomplicated acute myocardial infarction (AMI).

METHODS

A total of 53 patients was included, 27 of whom were randomized to a supervised training program (TRAINING group), and 26 to a CONTROL group, who received usual recommendations on physical exercise after AMI. All patients underwent cardiopulmonary stress testing and a speckle tracking echocardiography to measure several parameters of LV contraction mechanics at one month and five months after AMI. A p value < 0.05 was considered statistically significant for the comparisons of the variables.

RESULTS

No significant difference were found in the analysis of LV longitudinal, radial and circumferential strain parameters between groups after the training period. After the training program, analysis of torsional mechanics demonstrated a reduction in the LV basal rotation in the TRAINING group in comparison to the CONTROL group (5.9±2.3 vs. 7.5±2.9o; p=0.03), and in the basal rotational velocity (53.6±18.4 vs.68.8±22.1 º/s; p=0.01), twist velocity (127.4±32.2 vs. 149.9±35.9 º/s; p=0.02) and torsion (2.4±0.4 vs. 2.8±0.8 º/cm; p=0.02).

CONCLUSIONS

Physical activity did not cause a significant improvement in LV longitudinal, radial and circumferential deformation parameters. However, the exercise had a significant impact on the LV torsional mechanics, consisting of a reduction in basal rotation, twist velocity, torsion and torsional velocity which can be interpreted as a ventricular "torsion reserve" in this population.

The effect of exercise on left ventricular global longitudinal strain

Exercise improves measures of cardiovascular (CV) health and function. But as traditional measures improve gradually, it can be difficult to identify the effectiveness of an exercise intervention in the short-term. Left ventricular global longitudinal strain (LVGLS) is a highly sensitive CV imaging measure that detects signs of myocardial dysfunction prior to more traditional measures, with reductions in LVGLS a strong prognostic indicator of future CV dysfunction and mortality. Due to its sensitivity, LVGLS may offer useful method of tracking the effectiveness of an exercise intervention on CV function in the short-term, providing practitioners useful information to improve patient care in exercise settings. However, the effect of exercise on LVGLS is unclear. This systematic review and meta-analysis aimed to determine the effect exercise has on LVGLS across a range of populations. Included studies assessed LVGLS pre-post an exercise intervention (minimum 2 weeks) in adults 18 years and over, and were published in English from 2000 onwards. Study-level random-effects meta-analyses were performed using Stata (v16.1) to calculate summary standardized mean differences (SMD) and 95% confidence intervals (CI). 39 studies met selection criteria, with 35 included in meta-analyses (1765 participants). In primary analyses, a significant improvement in LVGLS was observed in populations with CV disease (SMD = 0.59; 95% CI 0.16-1.02; p = 0.01), however, no significant effect of exercise was observed in CV risk factor and healthy populations. In populations with CV disease, LVGLS could be used as an early biomarker to determine the effectiveness of an exercise regime before changes in other clinical measures are observed.

Cardiovascular responses to high-intensity stair climbing in individuals with coronary artery disease

Exercise-based cardiac rehabilitation leads to improvements in cardiovascular function in individuals with coronary artery disease. The cardiac effects of coronary artery disease (CAD) can be quantified using clinical echocardiographic measures, such as ejection fraction (EF). Measures of cardiovascular function typically only used in research settings can provide additional information and maybe more sensitive indices to assess changes after exercise-based cardiac rehabilitation. These additional measures include endothelial function (measured by flow-mediated dilation), left ventricular twist, myocardial performance index, and global longitudinal strain. To investigate the cardiovascular response to 12 week of either traditional moderate-intensity (TRAD) or stair climbing-based high-intensity interval (STAIR) exercise-based cardiac rehabilitation using both clinical and additional measures of cardiovascular function in individuals with CAD. Measurements were made at baseline (BL) and after supervised (4wk) and unsupervised (12 week) of training. This study was registered as a clinical trial at clinicaltrials.gov (NCT03235674). Participants were randomized into either TRAD (n = 9, 8M/1F) and STAIR (n = 9, 8M/1F). There was a training-associated increase in one component of left ventricular twist: Cardiac apical rotation (TRAD: BL: 5.6 ± 3.3º, 4 week: 8.0 ± 3.9º, 12 week: 6.2 ± 5.1º and STAIR: BL: 5.1 ± 3.6º, 4 week: 7.4 ± 3.9º, 12 week: 7.8 ± 2.8º, p (time) = 0.03, η2  = 0.20; main effect) and post-hoc analysis revealed a difference between BL and 4 week (p = 0.02). There were no changes in any other clinical or additional measures of cardiovascular function. The small increase in cardiac apical rotation observed after 4 weeks of training may indicate an early change in cardiac function. A larger overall training stimulus may be needed to elicit other cardiovascular function changes.

Prognostic Impact of Hybrid Comprehensive Telerehabilitation Regarding Diastolic Dysfunction in Patients with Heart Failure with Reduced Ejection Fraction—Subanalysis of the TELEREH-HF Randomized Clinical Trial

Aims: The objective of the study was to evaluate the effects of individually prescribed hybrid comprehensive telerehabilitation (HCTR) implemented at patients’ homes on left ventricular (LV) diastolic function in heart failure (HF) patients. Methods and results: The Telerehabilitation in Heart Failure Patients trial (TELEREH-HF) is a multicenter, prospective, randomized (1:1), open-label, parallel-group, controlled trial involving HF patients assigned either to HCTR involving a remotely monitored home training program in conjunction with usual care (HCTR group) or usual care only (UC group). The patient in the HCTR group underwent a 9-week HCTR program consisting of two stages: an initial stage (1 week) conducted in hospital and the subsequent stage (eight weeks) of home-based HCTR five times weekly. Due to difficulties of proper assessment and differences in the evaluation of diastolic function in patients with atrial fibrillation, we included in our subanalysis only patients with sinus rhythm. Depending on the grade of diastolic dysfunction, patients were assigned to subgroups with mild diastolic (MDD) or severe diastolic dysfunction (SDD), both in HCTR (HCTR-MDD and HCTR-SDD) and UC groups (UC-MDD and UC-SDD). Changes from baseline to 9 weeks in echocardiographic parameters were seen only in A velocities in HCTR-MDD vs. UC-MDD; no significant shifts between groups of different diastolic dysfunction grades were observed after HCTR. All-cause mortality was higher in UC-SDD vs. UC-MDD with no difference between HCTR-SDD and HCTR-MDD. Higher probability of HF hospitalization was observed in HCTR-SDD than HCTR-MDD and in UC-SDD than UC-MDD. No differences in the probability of cardiovascular mortality and hospitalization were found. Conclusions: HCTR did not influence diastolic function in HF patients in a significant manner. The grade of diastolic dysfunction had an impact on mortality only in the UC group and HF hospitalization over a 12–24-month follow-up in HCTR and UC groups.

Effects of High Intensity Interval Training Rehabilitation Protocol after an Acute Coronary Syndrome on Myocardial Work and Atrial Strain

Background andObjectives: Current guidelines on cardiac rehabilitation (CR) suggest moderate-intensity physical activity after acute coronary syndrome (ACS). Recent report have shown that high-intensity interval training (HIIT) could be more effective than moderate-intensity continuous training (MCT) in improving cardiac performance. Our aim was to analyze the effects of HIIT protocol after ACS on advanced echocardiographic parameters of myocardial function. Materials and Methods: In total, 75 patients with recent ACS, with or without ST segment elevation, were enrolled and compared with a control group of 50 age- and sex-comparable healthy subjects. Patients were randomized to perform a MCT training or HIIT-based rehabilitation program. A complete echocardiographic evaluation, including left ventricular (LV) and left atrial (LA) global longitudinal strain (GLS) and myocardial work (MW) through speckle-tracking analysis, was performed for all patients, before and after cardiac rehabilitation training. A cardiopulmonary exercise testing (CPET) was also performed at the end of the rehabilitation program. Results: Patients who followed the HIIT rehabilitation program showed improved LV diastolic function compared to the MCT group (E/e’: 3.4 ± 3.1 vs. 6.4 ± 2.8, respectively, p < 0.01). Similarly, LV systolic function showed significant improvement in the group of patients performing HIIT (ejection fraction: 53.1 ± 6.4 vs. 52.3 ± 5.4%, p < 0.01; GLS: −17.8 ± 3.8 vs. −15.4 ± 4.3, p < 0.01). In addition, LA strain was improved. MW efficiency was also increased in the HIIT group (91.1 ± 3.3 vs. 87.4 ± 4.1%, p < 0.01), and was closely related to peak effort measurements expressed in peak VO2 by CPET. Conclusions: In patients with recent ACS, the HIIT rehabilitation program determined reverse cardiac remodeling, with the improvement of diastolic and systolic function, assessed by standard echocardiography. In addition, cardiac deformation index as GLS, LA strain and MW efficiency improved significantly after HIIT, and were associated with functional capacity during effort.

New Ultrasound Technologies for Ischemic Heart Disease Assessment and Monitoring in Cardiac Rehabilitation

Owing to its ease of application, noninvasive nature, and safety, echocardiography is an essential imaging modality to assess cardiac function in patients affected by ischemic heart disease (IHD). Over the past few decades, we have witnessed a continuous series of evolutions in the ultrasound field that have led to the introduction of innovative echocardiographic modalities which allowed to better understand the morphofunctional abnormalities occurring in cardiovascular diseases. This article offers an overview of some of the newest echocardiographic modalities and their promising application in IHD diagnosis, risk stratification, management, and monitoring after cardiac rehabilitation.

Impact of Ramadan Fasting on Biochemical and Exercise Parameters Among Patients Undergoing Exercise-Based Cardiac Rehabilitation

BACKGROUND

Ramadan fasting is an important worship activity for Muslims. It is not known if fasting could have deleterious effect on cardiac patients joining cardiac rehabilitation (CR) program, especially during summer season.

AIM

To assess the effect of Ramadan fasting on biochemical and exercise parameters among patients undergoing 12-week exercise-based CR program.

PATIENTS AND METHODS

53 patients joining CR program in university hospital were included in the study. The patients were divided into two groups according to their Ramadan fasting status. Fasting group included 32 patients, while non-fasting group included 21 patients. All patients underwent supervised exercise-based CR during the month of Ramadan. Plasma osmolality, blood urea and serum creatinine were assessed before CR and during the last week of Ramadan. Lipid profile, echocardiography and exercise parameters were assessed before and after CR program.

RESULTS

The two groups were similar in baseline characteristics including: risk factors, osmolality, urea, creatinine, lipid profile and hemoglobin values, as well as ejection fraction and exercise parameters. After the program, both groups showed significant improvement in ejection fraction, total cholesterol, LDL and HDL levels. There was also improvement in duration of exercise reached and achieved METs before and after CR program in both groups. An important notice was that fasting did not significantly influence plasma osmolality in either group.

CONCLUSION

Ramadan fasting did not change serum osmolality or negatively affect the results of CR among cardiac patients. It appears to be safe to undergo exercise-based CR during Ramadan even in summer season.

The impact of high-intensity interval training on ventricular remodeling in patients with a recent acute myocardial infarction-A randomized training intervention pilot study

Background

Aerobic exercise training is associated with beneficial ventricular remodeling and an improvement in cardiac biomarkers in chronic stable heart failure. High‐intensity interval training (HIIT) is a time‐efficient method to improve V˙O2peak in stable coronary heart disease patients. This pilot study aimed to compare the effect of HIIT on ventricular remodeling in patients with a recent acute myocardial infarction (AMI).

Methods

Nineteen post‐AMI patients were randomized to either HIIT (n = 9) or usual care (n = 10). A cardiopulmonary exercise test (CPET), transthoracic echocardiography, and cardiac biomarker assessment (ie, N‐terminal pro B‐type natriuretic peptide levels and G protein‐coupled receptor kinase 2 expression) were performed before and after a 12‐week training intervention. CPET parameters including oxygen uptake efficiency slope (OUES) and V˙O2 at the first ventilatory threshold (V˙O2 VT1) were calculated. left ventricular (LV) structural and functional echocardiographic parameters including myocardial strain imaging were assessed.

Results

V˙O2peak and OUES improved solely in the HIIT group (P < .05 for group/time, respectively). There was a significant training effect for the improvement of peak work load in both groups (P < .05). O₂ pulse and V˙O2 at VT1 both improved only in the HIIT group (P < .05 for time, no interaction). HIIT improved radial strain and pulsed‐wave tissue Doppler imaging derived e′ (P < .05 for time, no interaction). Cardiac biomarkers did not change in either group.

Conclusions

In post‐AMI patients, HIIT lead to significant improvements in prognostic CPET parameters compared to usual care. HIIT was associated with favorable ventricular remodeling regarding certain echocardiographic parameters of LV function.

Noninvasive imaging assessment of rehabilitation therapy in heart failure with preserved and reduced left ventricular ejection fraction (IMAGING-REHAB-HF): design and rationale

Background:

Studies have shown significant benefits of exercise therapy in heart failure (HF) with a reduced ejection fraction (HFrEF) and HF with a preserved ejection fraction (HFpEF). The mechanisms responsible for the beneficial effect of exercise in HFrEF and HFpEF are still unclear. We hypothesized that the effect of exercise on myocardial remodeling may explain its beneficial effect.

Methods:

IMAGING-REHAB-HF is a single-center, randomized, controlled clinical trial using cardiac magnetic resonance imaging, vasomotor endothelial function, cardiac sympathetic activity imaging and serum biomarkers to compare the effect of exercise therapy in HFpEF (LVEF ≥ 45%) and HFrEF (LVEF < 45%). Subjects will be assessed at baseline and after 4 months. The exercise program will consist of three 60-min exercise sessions/week. The primary endpoints are the effect of exercise on myocardial extracellular volume (ECV), left ventricular (LV) systolic function, LV mass, LV mass-to-volume and LV cardiomyocyte volume. Secondary endpoints include the effect of exercise on vasomotor endothelial function, cardiac sympathetic activity and plasmatic biomarkers. Patients will be allocated in a 2:1 fashion to supervised exercise program or usual care. A total sample size of 90 patients, divided into two groups according to LVEF:HFpEF group (45 patients:30 in the intervention arm and 15 in the control arm) and HFrEF group (45 patients:30 in the intervention arm and 15 in the control arm) – will be necessary to achieve adequate power.

Conclusion:

This will be the first study to evaluate the benefits of a rehabilitation program on cardiac remodeling in HF patients. The unique design of our study may provide unique data to further elucidate the mechanisms involved in reverse cardiac remodeling after exercise in HFpEF and HFrEF patients.