The blood tests showed mild leukocytosis and an increased C-reactive protein level. The O₂ saturation was 98 % whilst breathing room air. The electrocardiogram demonstrated sinus tachycardia. The chest radiograph showed a moderate cardiomegaly, right lobe infiltrates, and blunting of the both costophrenic sulcus suggesting a small pleural effusion. Three days after admission, the symptoms became slightly aggravated despite being treated with empirical antibiotics for presumed community-acquired pneumonia. Transthoracic color Doppler echocardiography indicated an ejection fraction of 48 %, mild left ventricular enlargement, and moderate left atrial enlargement resulting in severe mitral regurgitation. The clinical symptoms and right pulmonary edema resolved quickly with intravenous furosemide treatment.