European Journal of Echocardiography 2006 7(5):383-386; doi:10.1016/j.euje.2005.07.004
Copyright © 2005, The European Society of Cardiology
Plowing the atrium and growing thrombi: Two cases of large atrial thrombi following ablative and surgical procedure for atrial fibrillation
Shemy Carassoa,b,*,
Rafael Kupersteina,b,
Eli Konenb,c,
Michael Gliksona,b and
Micha S. Feinberga,b
aHeart Institute, Sheba Medical Center, 52621 Tel Hashomer, Israel
bThe Sackler Faculty of Medicine, Tel Aviv University, Israel
cThe Department of Radiology, Sheba Medical Center, 52621 Tel Hashomer, Israel
Received 10 April 2005; received in revised form 20 June 2005; accepted after revision 7 July 2005.
* Corresponding author. Heart Institute, Sheba Medical Center, 52621 Tel Hashomer, Israel. Tel.: +972 3 530 2433; fax: +972 3 530 2407. carassos{at}netvision.net.il
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Abstract
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Aim We present two patients with a large left atrial (LA) thrombus
following invasive treatment for atrial fibrillation and inadequate
anticoagulation.
Methods and results Case 1: A 30-year-old woman, with a one-year history of symptomatic paroxysmal atrial fibrillation resistant to medical therapy, underwent catheter ablation for atrial fibrillation. Three days after the procedure the patient presented with dizziness, fatigue, rapid atrial fibrillation with a sub-therapeutic INR. Transesophageal echocardiography (TEE) revealed a large LA thrombus. Case 2: A 59-year-old male, with severe mitral regurgitation and chronic atrial fibrillation, underwent mitral valve repair and Cox–Maze procedure. Three months later, while asymptomatic, a follow-up transthoracic echocardiography a large posterior LA thrombus was imaged. His INR was also sub-therapeutic. Both patients were treated by enhancing anticoagulation and close echocardiographic follow-up. So far both patients have remained asymptomatic two months following discharge.
Conclusion Large LA thrombi detected by transthoracic echocardiography are a rare complication of the Cox–Maze procedure and radio-frequency ablation for atrial fibrillation, which may occur even in patients with restored normal sinus rhythm receiving inadequate anticoagulation therapy.
Keywords: Atrial fibrillation; Radio-frequency ablation; Maze procedure; Thrombus
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Case 1
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A 30-year-old woman, with a one-year history of symptomatic
paroxysmal atrial fibrillation resistant to medical therapy,
underwent catheter ablation with pulmonary vein isolation and
a mitral isthmus line, as described by Hocini et al.
1 Transthoracic
echocardiography showed a left ventricle of normal size and
wall thickness with normal systolic and diastolic function.
The left and right atria were enlarged (left atrial diameter=5.3cm)
without valvular disorders. The patient was treated with warfarin
with a target INR of 3.0. During the procedure the patient was
anticoagulated by unfractionated IV heparin, with a target activated
clotting time of 300s. In spite of multiple ablative attempts
sinus rhythm could not be restored. Three days after the procedure
the patient presented with dizziness, fatigue, rapid atrial
fibrillation and peripheral edema. Her INR was 1.8 (sub-therapeutic).
Transesophageal echocardiography (TEE) revealed a large thrombus
attached to the posterior aspect of the left atrium between
the four pulmonary veins, without noticeable increase of their
flow (
Fig. 1). Contrast enhanced cardiac computerized tomography
confirmed the size and morphology of the thrombus (
Fig. 2).
On repeated echocardiographic examinations during a two-month
period the thrombus did not seem to decrease in size or change
its appearance although she had been adequately anticoagulated
(INR between 2.5 and 3.4).
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Figure 1 (A) Transthoracic echocardiography, apical 4-chamber view demonstrating posterior left atrial thrombus (arrow) post-catheter-induced radio-frequency ablation. (B) Left atrial thrombus by transesophageal echocardiography (arrows). LA=Left atrium, LV=left ventricle, RA=right atrium, MV=mitral valve.
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Figure 2 (A) A multiplanar reformation of CT angiography shows a large mural thrombus (*) attached to the posterior wall of the left atrium (LA). (B) A virtual image of the left atrium as seen from the left atrial inferior wall shows the protruding thrombus (T) and free orifices of the pulmonary veins (arrows) and appendage (Ap).
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Case 2
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A 59-year-old male, with severe mitral regurgitation due to
mitral valve prolapse and chronic atrial fibrillation, underwent
mitral valve repair and Cox–Maze procedure using radio-frequency
and cryo-energies. The patient's immediate post-operative course
was unremarkable and he was discharged after 3 days in normal
sinus rhythm. Warfarin treatment with a target INR of 3.0 was
prescribed. Epistaxis precluded delivery of full anticoagulation
therapy, and the INR had been bellow 2.0 during follow-up. Three
months later, while asymptomatic, the patient underwent a routine
follow-up transthoracic echocardiography and a large posterior
left atrial thrombus was imaged (left atrial diameter=5.5) (
Fig.3).
Left ventricular function was normal and the repaired mitral
valve showed no significant stenosis or regurgitation. The INR
at that time was 1.3. TEE showed severe bi-atrial swirling and
a large posterior left atrial thrombus (
Fig. 3). The patient
was discharged on adequate oral anticoagulation treatment (INR
3–3.5). On a follow-up ambulatory transthoracic echocardiography
one month after discharge, the thrombus was no longer apparent
and the patient remained asymptomatic.
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Figure 3 (A) Transthoracic echocardiography, parasternal long-axis view demonstrating posterior left atrial thrombus post-Cox–Maze procedure (arrows). (B) Left atrial thrombus post-Cox–Maze procedure by transesophageal echocardiography (arrows). LA=Left atrium, LV=left ventricle, RA=right atrium, MV=mitral valve.
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Discussion
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The expected improved symptomatic outcome of invasive procedures
for the treatment of atrial fibrillation may include a reduced
risk for embolic events resulting from left atrial thrombi.
2,3 Left atrial thrombus formation secondary to invasive procedures
for atrial fibrillation has been rarely reported.
4 Thrombi attached
to a mapping catheter or sheaths have been shown to form during
catheter based procedures.
5 Left atrial catheter based ablative
and surgical procedures can provide a thrombogenic milieu with
increased levels of D-dimmers and slow flow due to atrial stunning.
6–8 The sites of the thrombi within the left atria in both cases
link its formation to the ablation and surgical site. A similar
observation was previously reported with thrombus adherence
to the Cox–Maze incision line.
4 All cases occurred in
patients with inadequate anticoagulation. Large protruding mobile
left atrial thrombi seem to carry a high embolic risk. Evacuation
of these thrombi can be effectively achieved by surgical thrombectomy;
there is no assurance, however, that they will not reformat.
We chose a conservative approach by intensifying anticoagulation.
So far both patients have remained asymptomatic two months following
discharge.
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Conclusion
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Large left atrial thrombi detected by transthoracic echocardiography
are a rare complication of the Cox–Maze procedure and
radio-frequency ablation for atrial fibrillation. The two patients
presented show that LA thrombus formation occurs after LA interventions
for atrial fibrillation. It appears that effective anticoagulation
after ablation of AF is important in the prevention of thrombus
formation, and especially so in patients with enlarged LA, regardless
of sinus rhythm restoration.
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References
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- Hocini M., Sanders P., Jais P., Hsu L.F., Takahashi Y., Rotter M., et al. Techniques for curative treatment of atrial fibrillation. J Cardiovasc Electrophysiol (2004) 15(12):1467–1471.[CrossRef][ISI][Medline]
- Cox J.L., Ad N., Palazzo T. Impact of the maze procedure on the stroke rate in patients with atrial fibrillation. J Thorac Cardiovasc Surg (1999) 118(5):833–840.[Abstract/Free Full Text]
- Raanani E., Albage A., David T.E., Yau T.M., Armstrong S. The efficacy of the Cox/maze procedure combined with mitral valve surgery: a matched control study. Eur J Cardiothorac Surg (2001) 19(4):438–442.[Abstract/Free Full Text]
- Aoyagi S., Tayama E., Fukunaga S., Akaiwa K.I., Takagi K., Shojima T. Left atrial thrombosis following mitral valve repair and maze procedure: case report. J Heart Valve Dis (2003) 12(6):714–716.[ISI][Medline]
- Ren J.F., Marchlinski F.E., Callans D.J. Left atrial thrombus associated with ablation for atrial fibrillation: identification with intracardiac echocardiography. J Am Coll Cardiol (2004) 43(10):1861–1867.[Abstract/Free Full Text]
- Kahn I.A. Atrial stunning: basics and clinical considerations. Int J Cardiol (2003) 92(2–3):113–128.[CrossRef][ISI][Medline]
- Sparks P.B., Jayaprakash S., Vohra J.K., Mond H.G., Yapanis A.G., Grigg L.E., et al. Left atrial "stunning" following radiofrequency catheter ablation for chronic atrial fibrillation. J Am Coll Cardiol (1998) 32(2):468–475.[Abstract/Free Full Text]
- Manolis A.S., Melita-Manolis H., Vassilikos V., Maounis T., Chiladakis J., Christopoulou-Cokkinou V., et al. Thrombogenicty of radiofrequency lesions: results with serial D-dimmer determinations. J Am Coll Cardiol (1996) 28(5):1257–1261.[Abstract]
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Case 1