Details of patients who developed LA thrombi at repeat ablation
The time to repeat ablation in the three patients who developed thrombi was 1,449, 515, and 224 days after the initial session (Table 4). All patients underwent TEE before the first session. Patient 1 was a 44-year-old man with paroxysmal AF. He had a recurrence 6 months after the first session, but antiarrhythmic drug administration was able to suppress the AF occurrence thereafter. Anticoagulation, warfarin was discontinued with reference to the low-risk profile of this patient (CHADS2 score 0). Three years later, he returned to our hospital because of the frequent occurrence of AF and underwent a repeat session. Apixaban was administered alternatively prior to the procedure. TEE showed a thrombus attached to the LAA wall with a significant grade 2 SEC. Patient 2 was a 38-year-old man with persistent AF. He had a history of heart failure with reduced LVEF 33% before the first session and a history of LA thrombus prior to the initial session. After successful first ablation, sinus rhythm was maintained, with a remarkable improvement in LVEF. However, atrial flutter with a high-rate ventricular response occurred after 1 year, which could not be controlled by anti-arrhythmic drugs, and required repeat ablation. Echocardiography showed a severely impaired LVEF of 19% and dilated LAD of 40.7 mm, which might be suggestive of tachycardia-induced cardiomyopathy. Although the patient continued taking dabigatran from the first session onwards, the TEE performed before the repeat ablation revealed LAA thrombi with SEC grade 3. The patient had already been examined by contrast-enhanced CT prior to the repeat ablation and the absence of LA thrombi was confirmed, but the examination time was 29 days before the procedure. We speculated that the severely decreased LVEF due to atrial flutter and heart failure may be a possible explanation for the development of thrombi in this case. Patient 3 was a 62-year-old man with persistent AF. He underwent extensive LA ablation in addition to PV isolation with administration of apixaban 10 mg at the initial session; however, AF recurred after 3 months. Before the repeat ablation, he experienced an intestinal hemorrhage event causing hospitalization at another facility, and the attending doctor reduced the dose of apixaban to 5 mg, which was an inappropriate reduced dose, although recurrence AF persisted. The inappropriately reduced dose in this case may be a possible reason for the LAA thrombi with a dense grade 2 SEC. All three patients had no neurological function abnormalities and no thromboembolic events occurred thereafter.