Lipomatous Hypertrophy of the Interatrial Septum Presenting with Atrial Arrhythmias

A 60-year-old woman with a history of chronic obstructive pulmonary disease and diabetes mellitus presented with a 5-day history of severe shortness of breath and productive cough. Her blood pressure was 86/54 mmHg; her oxygen saturation, 70%; and her heart rate, 110 beats/min. Physical examination revealed an irregularly irregular heart rate and bilateral expiratory wheezing. The patient needed urgent intubation in the intensive care unit because of acute hypoxic respiratory failure. A computed tomographic angiogram of the chest incidentally showed a 5 × 3.5-cm lipomatous mass in the upper two thirds of the interatrial septum (Fig. 1), with clear sparing of the fossa ovalis. Transthoracic and transesophageal echocardiograms (Figs. 2 and ​and3)3) and added color-flow Doppler mode (Fig. 4) confirmed lipomatous hypertrophy of the interatrial septum (LHIS)—about 5 cm at its greatest dimension—and restriction of right atrial filling with obstruction of the superior vena cava. Fig. 1. Computed tomogram of the chest shows the mass at its greatest dimension. Fig. 2. Transthoracic echocardiogram (apical 4-chamber view) shows the large mass in the posterior aspect of the interatrial septum. Fig. 3. Transesophageal echocardiogram (bicaval view) shows obstruction of the superior vena cava. Fig. 4. Transesophageal echocardiogram (bicaval view in color-flow Doppler mode) shows severe obstruction of the superior vena cava in systole and diastole. Most such lesions do not require invasive intervention. However, we thought that our patient's arrhythmias, filling restriction, and hemodynamic instability were secondary to the cardiac mass, and that surgical resection was the best option.1 Her hemodynamic status improved substantially after resection of the lesion.