Eccentric Exercise Rehabilitation After Myocardial Infarction

This clinical trial will evaluate a two-week eccentric exercise program conducted as part of comprehensive cardiac rehabilitation in patients after a heart attack (myocardial infarction). Eccentric exercise involves muscle contractions while the muscles are lengthening and may allow the muscles to work at a relatively high load with a lower cardiovascular and metabolic demand than traditional exercise. The main aim of the study is to determine whether eccentric exercise affects blood levels of proteins released or regulated in response to physical activity, including musclin, interleukin-6, and myostatin. The study will also evaluate whether the program improves physical performance and functional capacity. Participants will complete eccentric cycling exercise on a semi-recumbent cycle ergometer during a two-week cardiac rehabilitation program. Blood samples and physical-function measurements will be collected before and after the intervention.

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.