Giant left atrium: look before you leap into invasive procedures

摘要

A 67-year-old woman with history of mechanical mitral valve replacement for severe rheumatic mitral stenosis and permanent atrial fibrillation on warfarin presented with worsening dyspnoea and bilateral lower extremity swelling over the past 3 weeks. Physical examination revealed hypoxaemia with an oxygen saturation of 85% on room air, jugular venous distension, absent breath sound at right middle and lower lung zones, a crisp prosthetic valve click with a grade 1/6 holosystolic murmur at the apex and 2+ lower extremity oedema. Laboratory showed a brain natriuretic peptide of 799 pg/mL and an international normalized ratio of 2.7. A venous blood gas revealed respiratory acidosis with PaCO of 75 mm Hg. Chest X-ray (CXR) revealed cardiomegaly and complete opacification of right mid-to-lower lung zones ( ). Concerned for massive right-sided pleural effusion or right thoracic mass, a CT of the chest ( ) was performed, which showed massive left atrial dilatation with an enlarged main pulmonary artery and compressive atelectasis at right lung base. A transthoracic echocardiogram (TTE) showed severe left atrial enlargement ( ), left ventricular ejection fraction of 40%, normally functioning prosthetic mitral valve ( ; E velocity of 98 cm/s, mitral valve mean gradient annulus of 2.1 mm Hg and subvalvular velocity time integral of 35.2 cm), severe right ventricular (RV) enlargement with decreased RV function, moderate pulmonary hypertension (pulmonary artery systolic pressure of 59.6 mm Hg) and left ventricular outflow tract velocity time integral (VTI) of 26.7 cm. The normal architecture of the mediastinal structures was severely distorted by the giant left atrium causing restrictive lung physiology, vascular compression and subsequent pulmonary hypertension, RV failure and right-sided volume overload. She was aggressively diuresed with improvement of symptoms and planned for follow-up with cardiothoracic surgery to discuss surgical intervention.