Life-threatening huge right atrial diverticulum

Abstract

A 66-year-old male patient with chronic obstructive pulmonary disease presenting with exertional dyspnoea was referred to our hospital due to marked cardiomegaly on a chest X-ray at health check (Panel A). Twelve-lead electrocardiogram showed sinus rhythm and no ventricular preexcitation with delta waves (Panel B). The patient did not have a history of palpitation. Transthoracic echocardiography and enhanced computer tomography revealed a huge diverticulum (90 × 42 mm in diameter) protruding from the right atrial free wall, which compressed the right atrium and ventricle (Panels C and D; arrows). Slow contrast but no thrombus was seen within the diverticulum (Panel D). There was no tricuspid valve anomaly/dysfunction. Cardiac catheterization indicated no evidence of coronary artery stenosis, pulmonary hypertension, intracardiac shunt, and other abnormalities of the heart. To avoid an increasing risk of life-threatening rupture of the diverticulum, thrombus formation, paroxysmal arrhythmia, or haemodynamic derangement, we decided surgical resection of the right atrial diverticulum. The diverticulum presented a remarkable thin wall that resembled the amniotic membrane and had web-like communications to the atrium (45 × 55 mm) (Panels E–G). Through a standard mid-sternotomy approach, the right atrium diverticulum was resected and the communications were closed. Pathological examination of the resected specimen showed fibrous connective tissue without muscular layer (haematoxylin and eosin stain) (Panel H). Diverticulum of the right atrium is a rare congenital heart anomaly that can be diagnosed with atrial arrhythmias early in life, during infancy or childhood. However, some cases, in particular those with single diverticulum, may remain asymptomatic until late in life. In these cases, diverticulum may be found incidentally as enlargement of the cardiac silhouette on chest radiographs such as our patient. In view of the risk of life-threatening rupture of the diverticulum, thrombus formation, paroxysmal arrhythmia, or haemodynamic derangement, we recommend surgical resection of huge diverticulum to prevent sudden cardiac death regardless of symptoms. RA, right atrium; RV, right ventricle. Consent: The authors confirm that written consent for submission and publication of this case report including images and associated text has been obtained from the patient in line with COPE guidance. Conflict of interest: none declared.