Hypetrophic cardiomyopathy is a genetically and phenotypically heterogeneous disease that manifests itself as left ventricular hypertrophy not solely explained by abnormal loading conditions. Related pathology involves the left ventricular outflow tract, the mitral valve apparatus, the left atrium, the right chambers and the diastolic function. In the present paper we describe a rare case report of hypertrophic cardiomyopathy that is accompanied by severe mitral valve abnormalities resulting in eccentric mitral regurgitation that may have transformed a preexisting patent foramen ovale to secundum type atrial septal defect complicated by pulmonary hypertension.