Visualization of the left atrial appendage from the coronary sinus by intracardiac echocardiography

1547-5271/$-see front matter B 2014 Heart Rhythm Society. All rights reserved. PLSVC to the right superior pulmonary vein. She underwent electrophysiology study and ablation of an atypical right atrial flutter. The pre-procedure cardiac magnetic resonance imaging demonstrated shunt from the PLSVC into the right superior pulmonary vein with a Qp/Qs ratio of 1.5:1 (Figure 1A, white arrow). Electroanatomic mapping confirmed the presence of a PLSVC (Figure 1B). In order to exclude left atrial appendage (LAA) thrombus and to examine the presence of a right to left shunt, we took advantage of the coronary sinus system with its anatomical proximity to the LAA (Figures 1C and 1D). The intracardiac ultrasound catheter was advanced via the coronary sinus into the great cardiac vein (Figures 1C and 1D, yellow star). This