DOI:10.2214/AJR.05.0102
AJR 2006; 186:1317-1319
© American Roentgen Ray Society
Left Atrial Wall Hematoma After Radiofrequency Ablation for Atrial Fibrillation
Sarah Kelly1,
Simon G. Bicknell2 and
Sudheer Sharma3
1 Department of Radiology, University of British Columbia, Vancouver, BC,
Canada.
2 Department of Radiology, Lions Gate Hospital, 231 E 15th St., North Vancouver,
BC V7L 2L7, Canada.
3 Department of Cardiology, Lions Gate Hospital, Vancouver, BC, Canada.
Received January 20, 2005;
accepted after revision March 2, 2005.
Address correspondence to S. G. Bicknell
(sbicknel{at}interchg.ubc.ca).
Keywords: ablation • atrium • CT • radiofrequency
Introduction
Atrial fibrillation, the most common cardiac arrhythmia and an important
cause of stroke, is increasingly being managed with radiofrequency ablation of
the pulmonary vein ostia because many ectopic beats originate at this site.
Radiologists viewing images after ablation may identify complications such as
pulmonary vein stenosis. We report a case of left atrial intramural hematoma
after radiofrequency ablation.
Case Report
A 67-year-old woman had ectopic atrial tachycardia and atrial fibrillation
intolerant of standard rate control and rhythm control strategies. After an
electrophysiologic consultation, a permanent pacemaker was implanted in July
2004, and transvenous radiofrequency ablation of the atrioventricular node was
scheduled. Marked atrial tachycardia was found during an electrophysiologic
study in August 2004, and it was determined that discrete radiofrequency
ablation of the atrial reentrant tachycardia would be more beneficial than
atrioventricular node ablation. Electrophysiologic mapping in September 2004
showed inferoposterior left atrial tachycardia. The electrophysiologist was
unable to ablate the focus for technical reasons and abandoned the attempt
after several hours. The atrioventricular node was later ablated. The
procedure required 2 transseptal punctures under fluoroscopic guidance. The
patient was discharged from the hospital that evening. Over the next 2 days
she began to feel nonspecifically unwell with fatigue, lethargy, weakness, and
headaches. She denied the existence of specific cardiac symptoms. She was
taking warfarin and sotalol on a weaning schedule. The medical history
included breast carcinoma managed with lumpectomy and radiation therapy 7
years previously. All laboratory values were normal except that the
international normalized ratio was subtherapeutic at 1.2. A transthoracic
echocardiogram showed a smoothly contoured, 6 x 3 cm mass within the
posterior wall of the left atrium (Fig.
1A). CT showed a homogeneous, hyperdense, nonenhancing, intramural
mass consistent with hematoma (Figs.
1B and
1C). There was no evidence of
stenosis of the pulmonary veins (not shown) as a result of the hematoma.
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Fig. 1A —67-year-old woman with intramural hematoma in left atrium after
attempted radiofrequency ablation of pulmonary vein ostia. Transthoracic
echocardiogram in apical view shows smoothly contoured hematoma
(arrowheads) in posterior left atrial wall.
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Fig. 1B —67-year-old woman with intramural hematoma in left atrium after
attempted radiofrequency ablation of pulmonary vein ostia. CT scans through
chest show large intramural hematoma within posterior left atrium that is
hyperdense on unenhanced image (arrow, B) but more readily
visible after IV administration of contrast medium (arrow, C).
Note pacer wire in right atrium.
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Fig. 1C —67-year-old woman with intramural hematoma in left atrium after
attempted radiofrequency ablation of pulmonary vein ostia. CT scans through
chest show large intramural hematoma within posterior left atrium that is
hyperdense on unenhanced image (arrow, B) but more readily
visible after IV administration of contrast medium (arrow, C).
Note pacer wire in right atrium.
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Discussion
Transcatheter radiofrequency ablation has gained popularity as
nonpharmacologic therapy for cardiac arrhythmias. Some forms of atrial
fibrillation can be managed in this way because it has been shown that most of
the ectopic beats originate within sleeves of atrial myocardium that extend
into the pulmonary veins [1].
The treatment is desirable because when successful it allows patients to
discontinue antiarrhythmic and anticoagulation medications.
Transcatheter radiofrequency ablation typically is performed through a
percutaneous approach under fluoroscopic guidance. The foramen ovale is
probed, or a transseptal puncture is made if a patent foramen ovale is absent.
Once the left atrium has been accessed, the pulmonary veins are mapped for
identification of electrically conducting myocardial fascicles. Ablation of
these fascicles with radiofrequency energy is performed at or just within the
pulmonary vein ostia to reduce the risk of stenosis
[2].
Because transcatheter radiofrequency ablation is a relatively new
procedure, the gamut of complications has yet to be identified. Immediate
complications reported include pericardial effusion, embolic events, pulmonary
vein dissection, and bleeding secondary to anticoagulation
[3-5].
A complication that manifests later is pulmonary vein stenosis, which is mild
in most cases but when severe can result in pulmonary venoocclusive disease,
pulmonary vein thrombosis, and venous infarction
[6,
7]. Treatment failure with
persistent or recurrent atrial fibrillation occurs in less than 30% of cases
with careful patient selection.
Our patient became intolerant of her medications and needed rate control. A
permanent pacemaker was implanted first, and the initial plan was
atrioventricular node ablation. The possibility of ablation of the focal
atrial tachycardia led to rescheduling for a second procedure. The ectopic
tachycardia was mapped to the inferoposterior aspect of the left atrium, but
the ablation attempt was unsuccessful. The procedure required two transseptal
punctures of the interatrial septum. The ablation attempt was abandoned, and
the atrioventricular node was ablated to allow nonpharmacologic rate control
with the pacemaker. Transesophageal echocardiography was not used to aid the
transseptal puncture. Although transthoracic echocardiography was useful for
initial documentation of the hematoma, CT depicted not only the size but also
the extent of the mass. Knowledge of these features was critical in this case
to ensure the pulmonary veins were not compromised. Both imaging techniques
but especially CT showed that the hematoma was intramural and not
intraluminal.
To our knowledge, no cases of left atrial intramural hematoma have been
reported. Our patient's symptoms were nonspecific, and the mass found with
echocardiography was not suspected before the examination. We speculate that
the standard mapping and ablation catheters were probably not the cause of the
intramural hematoma given the precision of these instruments. It is more
probable that damage to the left atrial wall occurred during transseptal
puncture and caused the hematoma. At follow-up evaluation, the patient had had
no further sequelae, was symptom-free, and had a therapeutic international
normalized ratio. The hematoma continued to contract but did not resolve.
We conclude that intramural atrial hematoma is a possible complication of
radiofrequency ablation for atrial fibrillation, particularly in patients
taking anticoagulants. Routine use of transesophageal echocardiography for
precise guidance of transseptal puncture may be a method for mitigating the
risk of this complication. CT is best suited for documenting the extent of
such hematomas.
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Introduction
Case Report
