Left atrial diastolic parameters derived from STE correlate well with the extent of LA fibrosis. Thus, STE may be useful in the noninvasive assessment of LA fibrosis and selection of candidates for RFCA.

INTRODUCTION Atrial fibrillation (AF) increases the risk of thromboembolic events, including ischemic stroke, by promoting clot formation in the left atrial appendage (LAA). 1 The risk of stroke in patients with AF varies widely depending on age, clinical variables, and cardiac structure or function. Accordingly, several stroke risk stratification systems for AF patients have been developed, with the CHA 2 DS 2 VASc scale being the

Background-Transesophageal echocardiography (TEE) is the gold standard for the exclusion of thrombi in the left atrial appendage (LAA) before ablation for atrial fibrillation. Intracardiac echocardiography (ICE) is used to assist atrial fibrillation ablation; however, it can also be used for LAA imaging. The aim of our study was to determine whether ICE could replace TEE and to identify the optimal ICE placement for LAA visualization. Methods and Results-Seventy-six consecutive patients (56 men; mean age, 55±9.6 years) scheduled for atrial fibrillation ablation underwent TEE before the procedure and LAA assessment by ICE. An 8F AcuNav probe was introduced into right atrium, pulmonary artery, and coronary sinus. LAA structure was analyzed by the echocardiographer and electrophysiologist who were blinded to the results of TEE. ICE probe was positioned in the right atrium in all patients, in the pulmonary artery in 64 of 74 (86%) patients, and in the coronary sinus in 49 of 74 (66%) patients. The LAA was properly visualized in 56 of 64 (87.5%) patients from the pulmonary artery versus 13 of 49 (26%) patients from the coronary sinus (P<0.001). From the right atrium, the whole LAA cavity could not be seen in any patient. In those patients in whom LAA was visualized properly by ICE, a perfect agreement between ICE and TEE was obtained (both techniques detected LAA thrombus in 2 patients and excluded LAA thrombus in the remaining patients). Conclusions-ICE

Background Transesophageal echocardiography (TEE) remains the gold standard for exclusion of left atrial appendage (LAA) thrombus in patients scheduled for direct electrical cardioversion (DEC) or atrial fibrillation (AF) ablation. Recently, intracardiac echocardiography (ICE) of the pulmonary artery (PA) has been shown to provide excellent LAA images and to be useful in verification of equivocal TEE findings. Hypothesis ICE of the PA may have a role in detecting false‐positive TEE results. Methods Twenty‐one patients (12 male, age 65 ± 8 years, CHADS2VASC2 score [congestive heart failure, hypertension, age ≥ 75, age 65‐74, diabetes mellitus, stroke/TIA/thrombo‐embolism, vascular disease, sex female] = 2.2; HAS‐BLED score [hypertension, abnormal renal and liver function, stroke, bleeding, labile International Normalized Ratio, elderly, drugs or alcohol] = 1.1), in whom a thrombus in the LAA was detected during TEE before DEC or AF ablation, underwent ICE of the PA. Results On TEE, in 7 (33%) patients, the LAA thrombus was described as “solid” and in the remaining 14 (67%) as “soft.” Disagreement between the TEE and ICE (thrombus in TEE and no thrombus in ICE) was found in 9 (43%) patients. In the solid thrombus group, ICE confirmed thrombi existence in 6 and excluded thrombi in 1 patient. In the soft thrombus group, ICE confirmed thrombi in 6 patients and excluded thrombi in the remaining 8 patients. Of the demographic and clinical variables, only the longstanding persistent type of AF was significantly associated with the presence of an LAA thrombus detected both by TEE and ICE. Conclusions With TEE, a false positive of an LAA thrombus may be indicated, especially when a thrombus is described as soft rather than solid. Our study suggests that ICE may be a valuable option for verification of a TEE‐based diagnosis of a thrombus.

Introduction: Rivaroxaban is a direct factor Xa inhibitor used once a day for prevention of thrombotic events in patients with atrial fibrillation (AF). However, in a small proportion of subjects thrombus in the left atrial appendage (LAA) is present despite this treatment. The aim of this study was assess the efficacy of increased dose of rivaroxaban (15 mg twice daily) treatment for lysis of thrombus in the LAA. Material and methods: In the RIVA-TWICE prospective, open label study, with non-blinded patients and blinded outcome assessors, rivaroxaban 15 mg twice daily for 8 weeks was administered in patients with AF who had LAA thrombus despite standard 20 mg once a day therapy. Transesophageal echocardiography was performed at baseline and after 8 weeks. Blood samples were taken to measure the activity of the anti-Xa factor. Results: Fifteen patients (9 males, mean age: 63 ±10 years) were enrolled. Following 8 weeks of rivaroxaban 15 mg twice daily, complete resolution of thrombus in the LAA was observed in 7 (46.7%) patients. The mean activity of anti-Xa factor was significantly higher during rivaroxaban twice daily therapy compared with the standard dose. However, there were no significant differences between effectively and non-effectively treated patients. Conclusions: Rivaroxaban 15 mg twice daily seems to be safe and may dissolve LAA thrombus when standard rivaroxaban therapy is ineffective. Lower CHA 2 DS 2-VASc and HAS-BLED as well as preserved LAA emptying function identified responders.