Background. Most cases of RV failure follow existing or new-onset cardiac or pulmonary diseases or a combination of both, which may increase RV afterload, reduce RV contractility, alter RV preload or ventricular interdependence. Case report. A 71-year-old man was noted to be having shortness of breath. The electrocardiogram shows – sinus rhythm, heart rate 90 bpm, vertical heart axis, tall P wave and incomplete right bundle branch block. At Echocardiographic examination of the heart: severe dilatation of the right heart chambers, right ventricular systolic dysfunction, abnormal septal motion with D-shaped left ventricle, severe tricuspid regurgitation and severe pulmonary hypertention. All these ECG and EchoCG features are suggestive of right ventricular overload. Having elevated 5 times elevated D-dimers, first we have suspected a pulmonary embolism. Pulmonary angioCT reflect a subsegmental pulmonary embolism complicated with infarctionpneumonia. Also the spirometry indicates severe obstruction with hyperinflation. A further EchoCG investigation from an intermediate Echo window denotes an atrial septal defect “sinus venosus”~ 10 mm. The patient has been discharged with recommendation to visit a cardiac surgeon and to follow prescribed treatment with bisoprolol, spironolactone, losartan, torasemide, isosorbide mononitrate, warfarin, inhalator corticosteroids and antibiotics. Conclusions. Our patient has two important diseases that can cause the right heart failure: first is the atrial septal defect with bidirectional shunt, wich leads to chronic volume overload and RV dilation and the the second is chronic obstructive pulmonary disease (COPD) wich is the most prevalent cause of respiratory insufficiency and cor pulmonale. At this patient, also an additive effect to right heart failure has the subsegmental pulmonary embolism.