Comparison of Two Exercise Training Modes on Left Myocardial Regional Function After Myocardial Infarction Evaluated by 2D Strain Ultrasound

Comparison of Two Exercise Training Modalities on Left Myocardial Regional Function After MI (Myocardial Infarction) Evaluated by 2D Strain Ultrasound - a Randomized Controlled Bicentric Study

Ischemic cardiomyopathy, defined by a deficiency in oxygenation of the myocardium due to a narrowing of the coronary arteries, is a major problem for public health. Medicinally-treated or re-vascularized cardiovascular rehabilitation following myocardial infarction has shown undeniable benefits in decreasing the overall mortality rate (13-26%), cardiovascular mortality (26-36%) and morbidity, by controlling cardiovascular risk factors and improving tolerance to effort and consequently improving the quality of life. Since the integration of physical exercise into the rehabilitation programs of patients suffering from coronary disease in the mid-90s, and throughout the following decade, the exercise training program has mainly relied on moderately intense continuous exercises (CONT) the aim of which is to improve the aerobic capacity. These efforts typically consist of performing a submaximal exercise with an intensity of 50 to 80% of the maximum capacity for effort (established according to studies depending on the maximum or reserve heart rate or even peak power, measured when performing a first test, then a progressive and maximum test), and a constant duration (about 20 to 60 minutes). In the 2000s, under the aegis of Scandinavian teams, the intermittent mode (IT) appeared, characterized by alternating high intensity efforts of a short duration with active recuperation phases (Rognmo et al., 2004). Superiority of the IT mode over the CONT mode is generally observed on aerobic capacity for effort, usually gauged via the maximal oxygen consumption peak measured during a graded and maximum effort test. An important methodological bias in the comparison of the two modalities, within meta-analyses or even in the same randomized controlled trial, is the absence of control/pairing on the overall volume of training. At the present time, and to the best of our knowledge, there have been no studies to compare the effects of CONT versus IT modes on the systolic or diastolic function of the myocardial region by 2D-strain following myocardial infarction. The aim of our study was to compare the outcomes of 2D strain scans upon inclusion and after 8 weeks of cardiovascular physiotherapy for 2 groups of patients benefiting from a CONT or IT program.

This is a bi-centric randomised comparative superiority trial, blinded to the evaluator for 2 parallel groups (interventional intermittent training group "IT" vs a continuous training control group "CONT") with a 1:1 ratio.

Patients admitted for care at the cardiology departments of Nîmes University Hospital and the cardiology department of Avignon hospital for a first myocardial infarction dating back to less than 6 weeks will be pre-selected. The patients will receive both written and oral information about the study.

Patients are then referred to the Physical Medicine and Cardiac Rehabilitation departments at Nîmes University Hospital for the Nîmes site and the Lavarin Cardio Rehabilitation Center for the Avignon site for the inclusion visit at which the information about the study is given. Patients will be included in the study after signing a consent form.

The investigators then proceed with a maximal aerobic exercise test to evaluate cardiovascular endurance capacities and the suitability of the cardiovascular training program. Cardiac ultrasound is also performed, questionnaires about the quality of life are administered and biological doses are measured.

Then a stratified randomisation on the patient's age and sex will be performed to assign the subject either to the "IT intermittent training group" group, the experimental group, or to the "CONT continuous training" group, the control group which corresponds to the general care usually given.

Comparison of these two groups constitutes the methodological framework for this research. In the "IT intermittent training group (the experimental group), the patient benefits from a retraining program according to intermittent mode for 8 weeks, with three 45-minute sessions per week.

In the "CONT continuous training" group (the control group), the patient benefits from a retraining program according to the continuous mode for 8 weeks, with three 40-minute sessions per week.

At the end of the retraining program, at 8 weeks, an exercise test and a 2D Strain scan are performed, biological doses are taken and quality of life questionnaires are handed out.

Each patient will be followed 2 months after inclusion. The duration of inclusion period will be 18 months. The total duration of the test will be 24 months.

Inclusion Criteria:

• patient must have given free informed consent and signed the consent form
• patient must be affiliated to or be covered by a health insurance scheme.
• patient must be an adult aged ≥ 18 to ≤ 75 years old.
• Patient must have had a first episode of myocardial infarction treated via medical treatment or by revascularization like a percutaneous transluminal angioplasty (only if the patient has had complete revascularization) at least 6 weeks previously.

Exclusion Criteria:

• The patient is participating in another intervention study or has taken part in another interventional study in the past 3 months
• The patient is in an exclusion period determined by a previous study
• The patient is often under curatorship, tutorship or advisorship.
• It is impossible to give the patient clear information
• The patient refuses to sign the consent form
• The patient is pregnant, about to give birth or breastfeeding
• The patient has a contraindication for retraining
• The patient has a prosthetic heart valve
• The patient has severe valve disorder
• The patient requires cardiac stimulation
• The patient has an automatic implantable defibrillator
• The patient has sinus tachycardia, sinus bradycardia or sinus arrhythmia
• The patient has non-controlled high blood pressure
• The patient has a ventricular ejection fraction < 45%
• The patient has already participated in a cardiac rehabilitation program less than a year before
• The patient has a relapse of myocardial ischaemia during the study