A Case of Right Ventricular Dysfunction with Right Ventricular Failure Secondary to Obesity Hypoventilation Syndrome

BACKGROUND Obesity hypoventilation syndrome (OHS) is characterized by a body mass index (BMI) ≥30 kg/m², daytime hypercapnia, an arterial carbon dioxide tension ≥45 mmHg, and obstructive sleep apnea (OSA). OHS can lead to pulmonary hypertension. It has not been clearly demonstrated that OHS with pulmonary hypertension can lead to right ventricular dysfunction and right heart failure. A case is presented of right ventricular dysfunction and right ventricular failure secondary to OHS. CASE REPORT A 53-year-old man, who was morbidly obese with a BMI of 75 kg/m², presented with shortness of breath (SOB) and hypercapnia. He had never smoked but had a history of severe OSA and hypertension. On examination, the patient was obese with normal lung auscultation and mild pitting edema of the lower extremities. A spiral computed tomography (CT) angiogram showed no evidence of pulmonary embolism or interstitial lung disease. Pulmonary function testing showed no obstructive airway disease and a normal diffusion capacity. Two-dimensional transthoracic echocardiogram (TTE) showed normal left ventricular function and a dilated right ventricle (RV) with a flattened septal wall, moderate tricuspid regurgitation, and an estimated right ventricular systolic pressure of 55-60 mmHg. The patient was discharged on continuous positive airway pressure (CPAP) and oxygen at night, and as needed during the day. CONCLUSIONS This report has shown that OHS without underlying causes of alveolar hypoventilation can result in isolated right ventricular dysfunction and right ventricular failure.