Eccentric Exercise Rehabilitation After Myocardial Infarction

Exercise-based cardiac rehabilitation is an important component of secondary prevention after myocardial infarction. However, some patients experience reduced exercise tolerance or fear of physical activity, which may limit participation in rehabilitation and contribute to physical deconditioning, loss of muscle mass, and reduced functional capacity.

Eccentric exercise is characterized by muscle contractions performed while the muscle is lengthening. Compared with traditional concentric exercise, eccentric exercise can provide a relatively high mechanical load to skeletal muscles while requiring lower oxygen consumption and imposing a lower metabolic demand. For this reason, eccentric training may be a useful rehabilitation strategy for patients who have limited exercise tolerance after myocardial infarction.

The intervention will consist of a two-week eccentric cycling program performed on a semi-recumbent cycle ergometer as part of comprehensive cardiac rehabilitation. The training is intended to provide controlled loading of the lower-limb muscles while limiting excessive cardiovascular strain.

The primary scientific objective is to evaluate changes in the molecular response to eccentric exercise, with particular emphasis on circulating myokines and exerkines. Blood concentrations of musclin, interleukin-6, and myostatin will be assessed before and after the rehabilitation period. The study will also evaluate changes in physical performance, muscle function, and functional exercise capacity using the assessments specified in the study protocol.

The findings may help determine whether eccentric exercise produces beneficial molecular and functional adaptations in patients undergoing cardiac rehabilitation after myocardial infarction.

Inclusion criteria

• Documented history of myocardial infarction confirmed by medical records.
• Qualification for stage I comprehensive inpatient cardiac rehabilitation.
• Clinically stable condition allowing participation in exercise-based cardiac rehabilitation.
• New York Heart Association functional class I or II.
• Moderate or good exercise tolerance, defined as an exercise capacity of at least 5 metabolic equivalents, assessed during an exercise test.
• No cardiovascular contraindications to exercise testing or participation in exercise-based cardiac rehabilitation.
• Ability to understand the study procedures and follow the instructions provided by the study personnel.
• Provision of written informed consent to participate in the study.

Exclusion criteria

• Any contraindication to exercise-based cardiac rehabilitation or exercise testing.
• Acute myocardial infarction within the first 4 days before planned initiation of exercise rehabilitation.
• Unstable angina.
• Significant left main coronary artery stenosis considered a contraindication to exercise by the treating cardiologist.
• Symptomatic cardiac arrhythmias.
• Symptomatic severe aortic stenosis.
• Decompensated heart failure.
• Acute pulmonary embolism or pulmonary infarction.
• Deep vein thrombosis.
• Recent or mobile intracardiac thrombus.
• Acute myocarditis, endocarditis, or pericarditis.
• Aortic dissection.
• Symptomatic acquired second- or third-degree atrioventricular block without appropriate cardiac pacing.
• Poorly controlled arterial hypertension.
• Recent stroke or transient cerebral ischemic event.
• Any acute or uncontrolled non-cardiovascular condition that may interfere with exercise testing or worsen during exercise, including febrile illness, clinically significant electrolyte abnormalities, uncontrolled hyperthyroidism, or clinically significant anemia.
• Physical or cognitive impairment preventing safe completion of the study procedures, exercise testing, or training intervention.
• Inability or unwillingness to provide written informed consent.