Immediate disappearance of large thrombus in left atrium without evidence of systemic embolization after heparin treatment.

We report an unusual case with giant left atrial thrombus which disappeared soon after starting anticoagulation without evidence of further systemic embolism. A 75-year-old female with non-valvular atrial fibrillation suddenly complained of pain of her right arm and left leg. Contrast-enhanced computed tomography showed occlusion of right brachial and left popliteal arteries. Transesophageal echocardiography (TEE) revealed a low echoic thrombus attached to the left atrial appendage. She was administered sufficient heparin to maintain activated partial thromboplastin time for 70-90 s. Forty-eight hours later when she was subject to surgical thrombectomy, the thrombus was found to have completely disappeared by TEE without further systemic embolization. This case provides information regarding variability of time for anticoagulation-related resolution of left atrial thrombus associated with atrial fibrillation.