A 69 year old male patient with mild non ischemic cardiomyopathy, baseline EF of 47%, received a dual chamber pacemaker with a direct left bundle branch lead for complete heart block. 3830 lead was inserted intraseptally according to published recommendations with a resultant QRS of 103 ms. One month later patient presented with severe heart failure. Echocardiogram showed significant dyssynchrony and EF of 21%. Patient remained highly symptomatic despite aggressive medical therapy and exclusion of other causes of heart failure. An upgrade to a bi-ventricular pacing system was performed. At 1 month follow up, patient was no longer exhibiting heart failure symptoms, EF had improved back to baseline (46%) with improvement in dyssynchrony.

Transesophageal echocardiography (TEE) is the gold standard for diagnosing intracardiac masses (1). Sometimes, its unusual location, size, and patient presentation can pose significant diagnostic challenges. Here we report a rare case of large intra-cardiac vegetation mimicking a cardiac tumor.