Canadian Journal of Cardiology 30 (2014) 465.e5e465.e6

Images in Cardiology

Thrombus Formation in the Left Atrial Appendage During Catheter Ablation for Atrial Fibrillation Under Sufficient Heparinization Takehiro Kimura, MD, PhD, Seiji Takatsuki, MD, PhD, Kojiro Tanimoto, MD, PhD, Yoshinori Katsumata, MD, PhD, Takahiko Nishiyama, MD, PhD, Kohei Inagawa, MD, PhD, Nobuhiro Nishiyama, MD, PhD, Yoko Tanimoto, MD, PhD, Yoshiyasu Aizawa, MD, PhD, and Keiichi Fukuda, MD, PhD Department of Cardiology, Keio University School of Medicine, Tokyo, Japan

A 76-year-old man with hypertension and congestive heart failure (CHADS2 [Congestive Heart Failure, Hypertension, Age, Diabetes, Stroke/Transient Ischemic Attack] ¼ 3; CHA2DS2-VASc (Congestive Heart Failure, Hypertension, Age [75 y], Diabetes, Stroke/Transient Ischemic Attack, Vascular Disease, Age [65-74 y], Sex [Female] ¼ 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. The ICE-CHIP (Intra-Cardiac Echocardiography Guided Cardioversion) study revealed that ICE imaging in which ICE was placed in the RA was less sensitive for LAA thrombus identification than was TEE.1 In this study, we positioned the ICE catheter in the PA, which offered better visualization of the LAA than did catheter placement in the RA. ICE advanced in the PA might therefore be useful for detecting periprocedural thrombi. The patient was substantially older with a high CHADSVASc score and radiofrequency application near the LAA, and these are all factors that could be associated with thrombus formation and subsequent stroke. Most importantly, it should be noted that thrombus formation in the LAA is possible despite sufficient anticoagulation therapy with heparin during catheter ablation procedures.

Received for publication December 4, 2013. Accepted January 14, 2014.

Supplementary Material To access the supplementary material accompanying this article, visit the online version of the Canadian Journal of Cardiology at and at 1016/j.cjca.2014.01.008.

Corresponding author: Takehiro Kimura, MD, PhD, Department of Cardiology, Keio University School of Medicine, 35 Shinanomachi Shinjukuku Tokyo, Japan 160-8582. Tel.: þ81-3-3353-1211; fax: þ81-3-5363-3875. E-mail: [email protected] See page 465.e5 for disclosure information.

Disclosures The authors have no conflicts of interest to disclose. Reference 1. 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;3:571-7.

0828-282X/$ - see front matter Ó 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.


Canadian Journal of Cardiology Volume 30 2014

Figure 1. Images of the 5-second ICE (Biosense Webster, Diamond Bar, CA) (A-C; Video 1 , 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.

Thrombus formation in the left atrial appendage during catheter ablation for atrial fibrillation under sufficient heparinization.

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