A 48 year old man presents 30 minutes after losing consciousness and falling down. His wife witnessed the episode, and relates that he was unconscious for around 5 minutes. There were no abnormal movements; nor was there frothing at the mouth or incontinence. He has had 2 similar episodes during the past 10 months, with complete recovery afterwards. The most recent episode was 6 months ago. He also lost 12 kg of weight during this period, while his personality has subtly changed over time. A recent check up was negative for diabetes, hypertension and dyslipidemia. His surgical and family histories are unremarkable.
There are hypodense opacities suggestive of old infarcts in the right parietal and left occipital lobes. There are no features suggestive of intracranial hemorrhage, or space occupying lesions.
The ECG is in sinus rhythm. A left anterior fascicular block is noted. No other abnormalities are seen.
Both the capillary blood glucose and serum electrolytes are within normal parameters.
The transesophageal echocardiogram reveals a 4 x 2.5 x 2.5 cm mass in the left atrium, which prolapses through the mitral valve in diastole.