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.