[A case of left atria subendocardial thrombus with 
sick sinus syndrome].

The clinical data for a patient with sick sinus syndrome was retrospectively analyzed. The patient was treated because of his heart palpitations and the increased chest pain. The patient admitted to the hospital under consideration for the left atrial tumor dependent on the echocardiography findings. After the CT scan and the dynamic ECG examination, the patient successfully underwent the left atrial tumor resection, atrial septal repair and cardiac pacing lead installation. The postoperative pathological diagnosis showed that the infective endocarditis and left atrial thrombus in left atrium was cured. The patient was discharged after postoperative anti-inflammatory therapy. By analyzing the reasons for misdignosis before or during surgery, the possible mechanisms for left atrial subendocardial thrombus have been found. This study suggests that it is necessary to combine imaging diagnosis and clinical observations to distinguish tumor from excrescence.