Canadian Journal of Cardiology
Images in Cardiology| Volume 30, ISSUE 4, P465.e5-465.e6, April 2014

Thrombus Formation in the Left Atrial Appendage During Catheter Ablation for Atrial Fibrillation Under Sufficient Heparinization

Published:January 21, 2014DOI:
      A 76-year-old man with hypertension and congestive heart failure (CHADS2 [Congestive Heart Failure, Hypertension, Age, Diabetes, Stroke/Transient Ischemic Attack] = 3; CHA2DS2-VASc (Congestive Heart Failure, Hypertension, Age [≥75 y], Diabetes, Stroke/Transient Ischemic Attack, Vascular Disease, Age [65-74 y], Sex [Female] = 4) underwent catheter ablation for 7-month persistent atrial fibrillation (AF). Intracardiac echocardiography (ICE) (Soundstar Biosense Webster, Diamond Bar, CA) advanced in the pulmonary artery (PA) through the right atrium (RA) and the right ventricle showed no thrombi in the left atrial appendage (LAA) with a flow velocity of 7-18 cm/s during AF. Both pulmonary veins were isolated circumferentially 12 hours after the last intake of dabigatran. AF was terminated by intracardiac cardioversion, followed by linear ablation at the lateral mitral isthmus to treat the induced atrial tachycardia. At the end of the session, ICE imaging revealed a solid 3 × 4 mm mobile mass in the tip of the LAA (Fig. 1A-C; Video 1 view video online) observed from the PA (Fig. 1D). The activated clotting time was maintained over 300 seconds throughout the procedure by intravenous administration of heparin. Before ablation, examination by cardiac computed tomography detected a remarkable incomplete enhancement in the LAA without thrombi (Fig. 1E). The left atrial size on transthoracic echocardiography was 4.6 cm, and the ostial flow velocity of the LAA measured using transesophageal echocardiography was 30-36 cm/s during AF with evidence of spontaneous echo contrast without thrombi (Fig. 1F). LAA angiography during ablation showed no defect in the LAA.
      Figure thumbnail gr1
      Figure 1Images of the 5-second ICE (Biosense Webster, Diamond Bar, CA) (A-C; , view video online 1) and CARTO (Biosense Webster) (D, left anterior oblique view) during ablation. Computed tomographic scan (E) and transesophageal echocardiogram (F) before ablation are shown.
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        • Saksena S.
        • Sra J.
        • Jordaens L.
        • et al.
        A prospective comparison of cardiac imaging using intracardiac echocardiography with transesophageal echocardiography in patients with atrial fibrillation: the intracardiac echocardiography guided cardioversion helps interventional procedures study.
        Circ Arrhythm Electrophysiol. 2010; 3: 571-577