A Contemporary Review of the Effects of Exercise Training on Cardiac Structure and Function and Cardiovascular Risk Profile: Insights From Imaging

Impact of exercise training on myocardial contractile functions assessed by cardiac magnetic resonance in post-myocardial infarction patients

Background

Improvement of functional capacity and mortality reduction in post-MI patients were found to be associated with regular exercise training. The cardiac magnetic resonance (CMR) is considered the most accurate non-invasive modality in quantitative assessment of left ventricular (LV) volumes and systolic functions. Our main objective was to investigate the impact of exercise training on LV systolic functions in patients post anterior MI using CMR. 32 patients on recommended medical treatment 4 week after having a successful primary PCI for an anterior MI were recruited, between May 2018 and May 2019. They were divided into two groups, training group (TG): 16 assigned to a 12 week exercise training program and control group (CG): 16 who received medical treatment without participating in the exercise training program. Treadmill exercise using modified Bruce protocol was done to TG before and after the training program in order to record the resting and maximum HR, metabolic equivalent (MET), and calculate HR reserve. CMR was performed for all patients 4 weeks after PCI and was repeated after completion of the study period to calculate ejection fraction (EF), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume (LVEDV), and wall motion score index (WMSI).

Results

100% were males. 6 patients from CG dropped during follow-up, no statistically significant difference between the two groups regarding age, BMI, smoking status, hypertension, diabetes mellitus and dyslipidemia. Using the CMR, the TG showed significant improvement in EF (36.6 ± 14.2% to 43.1 ± 12.4%; P < 0.001) and WMSI (2.03 ± 0.57 to 1.7 ± 0.49; P < 0.001), without statistically significant change in LV volumes. Regarding CG no significant changes in EF, WMSI, LV volumes were found. There was significant improvement in EF and WMSI change before and after study in TG vs. CG [6.5 (2.3–9.0) vs. − 2.0 (− 6.8 to 1.3), P value < 0.001] and [− 0.3 (− 0.5 to 0.1) vs. 0.1 (− 0.1 to − 0.5), P value 0.001] respectively.

Conclusions

12 weeks of exercise training program in post-MI patients have a favorable impact on LV global and regional systolic functions without adversely affecting LV remodeling (as assessed by CMR).

Left Ventricular Diastolic Response to Isometric Handgrip Exercise in Physically Active and Sedentary Individuals

Aims: This study aims to investigate the diastolic left ventricular (LV) response to isometric handgrip exercise among healthy middle-aged men with high physical activity levels, versus matched sedentary individuals. Methods: Two groups of 10 men aged 41−51 years were studied. Men in the first group had high weekly self-reported physical activity levels (>3000 METs × min/week). In comparison, men in the second group reported low physical activity levels (<300 METs × min/week). An isometric handgrip exercise (IHE) stress echocardiography test was performed in all of them. Results: Both groups showed a similar and statistically significant increase in heart rate, systolic, diastolic, and mean arterial pressure following IHE. The group of active men under study did not show a statistically significant change in the ratio of early diastolic mitral valve inflow velocity to early diastolic lateral wall tissue velocity (E/e’ ratio) in response to IHE. Conversely, the inactive participants’ E/e’ ratio was higher at peak activity in the isometric handgrip exercise. Conclusions: Apparently, healthy middle-aged men with high levels of physical activity seem to have an improved lusitropic cardiac function compared to men with low levels of physical activity, as observed by the different diastolic LV responses induced by isometric handgrip exercise.

Irisin is an Effector Molecule in Exercise Rehabilitation Following Myocardial Infarction (Review)

Background: Regular exercise is an effective non-pharmacological therapy for treatment and prevention of cardiovascular disease (CVD). The therapeutic benefits of exercise are mediated partly through improved vascular and increase in metabolic health. Release of exercise-responsive myokines, including irisin, is associated with beneficial effects of exercise in CVD patients.

Observations: The present review provides an overview of the role of exercise in cardiac rehabilitation of patients with myocardial infarction (MI). Further, the role of irisin as a motion-responsive molecule in improving vascular and metabolic health is explored. Possible mechanism of cardioprotective effect of irisin-mediated exercise on myocardial infarction are also summarized in this review.

Conclusion and significance of the review: Irisin is associated with reduced inflammation, antioxidant properties, and anti-apoptotic effect, implying that it is a potential key mediator of the beneficial effects of exercise on vascular and metabolic health. The findings show that irisin is a promising therapeutic target for treatment of patients with cardiovascular disease, particularly post-MI. Further research should be conducted to elucidate the potential mechanisms of cardioprotective effects of irisin and explored whether irisin induced by exercise exerts rehabilitation effects post-MI.

Effects of a Long-Term Wearable Activity Tracker-Based Exercise Intervention on Cardiac Morphology and Function of Patients with Cystic Fibrosis

Several studies have shown that patients with cystic fibrosis (CF), even at a young age, have pulmonary and cardiac abnormalities. The main complications are cardiac right ventricular (RV) systolic and/or diastolic dysfunction and pulmonary hypertension, which affects their prognosis. Exercise training (ET) is recommended in patients with CF as a therapeutic modality to improve physical fitness and health-related quality of life. However, questions remain regarding its optimal effective and safe dose and its effects on the patients’ cardiac function. The study aimed to provide a wearable activity tracker (WAT)-based ET to promote physical activity in CF patients and assess its effects on cardiac morphology and function. Forty-two stable CF individuals (aged 16.8 ± 3.6 years) were randomly assigned to either the intervention (Group A) or the control group (Group B). Group A participated in a 1-year WAT-based ET program three times per week. All patients underwent a 6-min walking test (6-MWT) and an echocardiographic assessment focused mainly on RV anatomy and function at the baseline and the end of the study. RV systolic function was evaluated by measuring the tricuspid annular plane systolic excursion (TAPSE), the systolic tricuspid annular velocity (TVS’), the RV free-wall longitudinal strain (RVFWSL), and the right ventricular four-chamber longitudinal strain (RV4CSL). RV diastolic function was assessed using early (TVE) and late (TVA) diastolic transtricuspid flow velocity and their ratio TVE/A. Pulmonary artery systolic pressure (PASP) was also estimated. In Group A after ET, the 6MWT distance improved by 20.6% (p < 0.05), TVA decreased by 17% (p < 0.05), and TVE/A increased by 13.2% (p < 0.05). Moreover, TAPSE, TVS’, RVFWSL, and RV4CSL increased by 8.3% (p < 0.05), 9.0% (p < 0.05), 13.7% (p < 0.05), and 26.7% (p < 0.05), respectively, while PASP decreased by 7.6% (p < 0.05). At the end of the study, there was a significant linear correlation between the number of steps and the PASP (r = −0.727, p < 0.01) as well as the indices of RV systolic function in Group A. In conclusion, WAT is a valuable tool for implementing an effective ET program in CF. Furthermore, ET has a positive effect on RV systolic and diastolic function.