A "non-rheumatic" giant left atrium.

Abstract

Sir, Giant left atrium (GLA) is a rare condition with a reported incidence of 0.3%. Definition of GLA is varied. Piccoli et al. defined the giant left atrium as a cardio-thoracic ratio on chest X-ray (CXR) of >0.7 combined with a left atrial anterior-posterior diameter of >8 cm on transthoracic echocardiography.[1] According to the definition by Isomura and coworkers, left atria larger than 6 cm in diameter are giant left atria.[2] Giant left atrium is commonly associated with longstanding rheumatic mitral valve regurgitation or mixed mitral disease with predominant regurgitation. The largest ever GLA reported to our knowledge measured 19.3 × 14.7 cm and was due to untreated rheumatic heart disease.[3] However, not many reports of “non-rheumatic” causes of GLA are available. The largest ever “non-rheumatic” GLA reported, measured 12 × 13 cm in a case of mitral valve prolapse.[4] A 22-year-old male was admitted with signs of acute decompensated heart failure. The physical examination revealed anterior precordial bulging with scoliosis, his blood pressure was 100/60 mmHg, his heart rate was 110/min with atrial fibrillation, neck veins were distended, and crepitations were present at the basal regions of his lungs. [Figure 1] A grade 3/6 pansystolic murmur and a diastolic flow murmur were present at the anterior axillary line, and there was peripheral edema. Chest radiography revealed cardiomegaly (cardiothoracic ratio, 0.74) leading to splaying of the carina, an elevated left main bronchus and severe thoracic scoliosis [Figure 2]. Echocardiogram showed massive left atrial enlargement, cleft anterior mitral leaflet, double mitral regurgitation jets, a small ostium primum atrial septal defect, and an (7 mm) inlet ventricular septal defect [Figures 3 and 4] — both with left to right shunts. A diagnosis of “Giant Left Atrium” (GLA) with partial atrioventricular septal defect was confirmed by cardiac computed tomography (CT) scan [Figures 5 and 6]. Maximum diameter of left atrium (LA) recorded by CT was 14.4 × 12.4 cm. [Figure 7] and LA volume was 840 ml. The patient was judged to be in New York Heart Association (NYHA) functional class IV. After initial attempt to stabilize him with infusion of furosemide (6 mg/hour) and isosorbide dinitrate (5 μg/min), he was referred to cardiac surgery department for LA size reduction and corrective surgery for the atrio-ventricular septal defect, as clinical and echo parameters predicted only a moderate pulmonary hypertension. Intra-operative findings confirmed the structural defects.[5] The patient's post-operative recovery was briefly punctuated by surgical wound infection; otherwise, patient has improved, with NYHA status at present class II/IV.Figure 1: Photo of the patient showing precordial bulging and scoliosisFigure 2: Chest radiography shows cardiomegaly, splaying of the carina, an elevated left main bronchus and scoliosisFigure 3: Echocardiogram showing massive left atrial enlargementFigure 4: Echocardiogram showing cleft anterior mitral leaflet with double mitral regurgitation jets; a small osteum primum atrial septal defect and an inlet VSDFigure 5: Cardiac computed tomography (CT) Scan showing dilated LAFigure 6: Cardiac CT Scan with 3D reconstruction showing dilated LAFigure 7: Maximum diameter of LA recorded by CT scan is 14.4 × 12.4 cmThis case probably represents the largest ever “non-rheumatic” GLA reported, demonstrating the extent to which a LA can expand even in a congenital heart disease condition. Although not many reports of “non-rheumatic” GLA are available but its identification is essential because of the complications associated. GLA can be associated with atrial fibrillation, thromboembolic complications, hemodynamic, and respiratory complications. GLA may lead to skeletal changes in the thorax related to direction of enlargement of LA; as in non-structural (postural) scoliosis seen in our case.[6] Surgical options for GLA are divided for either performing mitral valve surgery with left atrial volume reduction or performing mitral valve surgery alone.[7] A giant LA is an indication for the initiation of anti-coagulant therapy.