Severe Right Atrial and Ventricular Compression From a Massive Morgagni Hernia and Paralyzed Right Hemidiaphragm

A 57-year-old woman, with a history of pericardiectomy 20 years before, reported progressive dyspnea and orthopnea. A chest computed tomography scan showed a large anterior diaphragmatic (Morgagni) hernia containing a loop of transverse colon and omentum producing mass effect on the right atrium and ventricle. Significant right ventricular outflow obstruction and a small loculated pericardial effusion were confirmed on cardiac magnetic resonance imaging. A sniff test suggested minimal to no motion of the right hemidiaphragm.<br>Reduction of the herniated transverse colon and omentum was performed via laparotomy, followed by reconstruction of the diaphragmatic defect with Gore-Tex mesh along with drainage of the complex pericardial effusion. This led to resolution of her orthopnea. Due to ongoing exertional dyspnea and continued decline in pulmonary function, she underwent a right hemidiaphragm plication 4 months later. This led to significant improvement in her exercise capacity. At 6-year follow-up, the patient was symptom free with no radiographic recurrence.<br>