A left ventricular (LV) thrombus may develop as a complication of acute myocardial infarction, ventricular aneurysm, dilated cardiomyopathy, tako-tsubo transient apical ballooning, and myocarditis. Giant LV thrombi are extremely rare and have not been previously described following radiofrequency catheter ablation (RFCA). We present a case of a giant LV thrombus developing late after an RFCA procedure for ventricular tachycardia in a patient with a post-infarction LV aneurysm. An echocardiogram performed one month after discharge showed a large, homogenously dense, and slightly oscillating mass (28 × 21 mm), partially attached to the dyskinetic LV apex. With the diagnosis of giant LV thrombus, the patient began full anticoagulation treatment. Two dimensional echocardiography is an accurate non-invasive technique for the detection and follow up of LV thrombi. Factors such as the shape, size, mobility, and attachment of the thrombus to the subjacent LV myocardium influence the risk of embolic complications. One month later, on a repeat echocardiogram, the mass had slightly reduced its size (23 × 14 mm) showing ample oscillations. Oral anticoagulation treatment was intensified but two weeks later the thrombus was completely dislodged, occluding both iliac arteries. Anticoagulation treatment is not routinely recommended after LV RFCA procedures. Patients undergoing complex ablation interventions of left ventricular tachycardias associated with an aneurysm or severe left ventricular dysfunction might benefit from temporary oral anticoagulation to prevent thrombus formation. More importantly, an LV thrombus that on repeat transthoracic echocardiographic examinations becomes protruding and mobile should prompt us to consider intensive intravenous heparin, thrombolysis, or surgical thrombectomy.

Panel A: demonstration of a giant thrombus filling the left ventricular apical aneurysm. Panel B: after one month of full oral anticoagulation treatment the thrombus was reduced in size, particularly at its attachment to the apex of the left ventricle, becoming more mobile than before. Panel C: echocardiogram obtained immediately after the embolic episode in the lower extremities showing the absence of thrombus in the left ventricle.