Harmonica Exercises for Patients Undergoing Cardiac Rehabilitation.

Inclusion Criteria: patients participating in cardiac rehabilitation program Exclusion Criteria: * Decompensated heart failure, with symptoms in NYHA class II-IV within 3 weeks before admission to the Cardiac Rehabilitation Department * Poorly controlled hypertension (BP in office measurement \>160/100 mmHg) * Severe symptomatic heart disease (including valvular); * Other severe comorbidities, including those significantly limiting physical performance: chronic kidney disease with GFR \<30 ml/min/1.73m2 (according to the CKD-EPI formula), severe form of bronchial asthma/chronic obstructive pulmonary disease (stage C/D ), hypertrophic cardiomyopathy, significant cardiac arrhythmias (persistent/permanent atrial fibrillation, sustained supraventricular/ventricular tachycardia, multiple supraventricular/ventricular extrasystole \> 10,000/day), pulmonary embolism in the last 3 months, acute coronary syndrome in the last 7 days, peripheral arterial disease with claudication distance \<200 m, generalized active neoplastic process; * mental illness/dementia syndrome that prevents full cooperation with the examined person; * diseases of the musculoskeletal system that make it impossible to perform an exercise test; * contraindications to performing an exercise test; * contact allergy to the materials from which the body/cover of the harmonica is made, revealed during exercises * lack of consent to participate in the study