CASE PRESENTATION
Our patient is 69 years old gentleman known to have non-insulin dependent diabetes mellitus, essential hypertension, dyslipidaemia and mild renal impairment. He had atypical angina 7 years back with normal epicardial coronaries on coronary angiogram (CAG). He again had atypical chest pain one year back and underwent bike stress echo, which was negative for inducible ischemia at high workload. His echo till then showed preserved biventricular size and systolic function. He had mild LA dilatation with diastolic dysfunction.
He presented this time with 5 days history of variable threshold angina and progressive shortness of breath. He had associated upper back pain of similar intensity. His electrocardiogram (EKG) showed diffuse concave ST elevation in precordial leads and PR segment depression with highest highly sensitive troponin-I leak of 0.77ng/ml (normal value 0.02-0.06). He had pulmonary congestion on chest X-ray. In light of refractory angina and heart failure despite optimal medical management, He was taken up for urgent CAG, which again revealed normal epicardial coronaries. Subsequent labs were unremarkable. Later he underwent transthoracic echo (TTE) which showed a large mass occupying the whole of Left atrium (LA) and attached to the posterior wall and interatrial septum. The mass appeared inhomogeneous and cystic with multiple septations (Figure 1a and 1b). There was no colour flow observed through the mass. There was underlying moderate LA dilatation with interatrial septum (IAS) bulging into right atrium suggestive of high LA pressure. Left ventricular size and systolic function were normal. We went ahead with contrast echocardiography, which showed complete non-opacification of LA mass suggestive of avascular nature (Figure 2 and supplementary video 1). Computed tomography (CT) with contrast was primarily performed to rule out aortic dissection because of his presentation. But it as well was suggestive of large mass in the LA (Figure 3). To further characterise the mass, we performed transoesophageal echo (TEE) showing large well encapsulated mass with echo-density lower than underlying LA wall. There were multiple irregular sized cystic spaces with loosely bound septations (supplementary video 2). The mass was attached to IAS and extending till the base of posterior mitral leaflet and whole of posterior LA wall (Figures 4a, 4b and supplementary video 3 to 6). There was mild inflow obstruction with mean gradient across mitral valve of 5mmhg. There was no pulmonary venous obstruction noted. Our differential diagnosis at this point was cardiac hydatidosis, polycystic LA myxoma, LA dissection and LA hematoma.
Finally, cardiac magnetic resonance (CMR) imaging was performed which showed a large smoothly marginated LA mass measuring 5.1*6.3 centimetres related to posterior wall and IAS (Figures 5a and 5b) . It was not attached to Mitral valve with no extension beyond the confines of LA. The mass had slightly heterogenous signal intensity being moderately hypertense on spin echo sequences (black blood imaging, T2 weighted) and moderately hypointense on gradient echo (white blood imaging, T1 weighted cine). There was a suggestion that this mass could be thrombus.