Patient: Female, 29-year-old Final Diagnosis: Restrictive cardiomyopathy with isolated endomyocardial fibrosis of the right ventricle • tricuspid valve insufficiency Symptoms: Reduced exercise tolerance • dyspnea and heart rhythm disorders Medication: — Clinical Procedure: — Specialty: Cardiac Surgery • Cardiology Objective: Rare disease Background: The cardiotoxic effects of chemotherapy in cancer treatment can damage cardiomyocytes. A common link in the pathogenesis is the proliferation of fibroblasts and the increase of collagen synthesis, leading to development of common endomyocardial fibrosis. The walls of ventricles become rigid and their inability to relax prevents them from carrying the required amount of blood. The myocardial contractility gradually decreases and leads to ventricular dysfunction and signs of heart failure. Case Report: A 29-year-old woman with reduced exercise tolerance, dyspnea, and heart rhythm disorders was admitted to our hospital. Lymphoblastic leukemia had been diagnosed at the age of 8 years, and she underwent 8 courses of polychemotherapy. She had normal heart anatomy. At the current admission, the diagnostic protocol included echocardiography, computed tomography, cardiac catheterization, and angiocardiography. She was diagnosed with restrictive cardiomyopathy with isolated endomyocardial fibrosis of the right ventricle, and moderate tricuspid valve insufficiency NYHA class III. The patient underwent a right-sided bidirectional cavopulmonary connection with tricuspid valve repair. The early postoperative period was uneventful, and SVCp decreased to 14 mmHg. At discharge, the patient’s clinical condition had improved and tricuspid regurgitation was minimal. Conclusions: The one-and-a-half ventricular correction, commonly used in patients with Ebstein’s anomaly and RV dysfunction or in patients with congenital heart defects associated with RV hypoplasia, is proposed as the method of choice for cardiomyopathy type RV dysfunction.