International Journal of Arrhythmia 2013;14(1): 33-37.
Untitled Document
ECG & EP CASES
Catheter Ablation of Atypical Atrial Flutter after Cardiac Surgery Using a 3-D Mapping System
Myung-Jin Cha Seil Oh
Myung-Jin Cha, MD, Seil Oh, MD, PhD, FHRS Department of Internal Medicine, Seoul National University College of Medicine and Seoul National University Hospital, Seoul, Korea
Introduction
Electrophysiological study and fluoroscopyguided
radiofrequency (RF) catheter ablation
(RFCA) have become standard modalities for
treatment of paroxysmal supraventricular
tachycardia.1-2 However, there are serious
limitations in fluoroscopy-guided ablation
procedures, including poor resolution of soft tissue,
poor visualization of the site of origin, difficulty in
mapping complex arrhythmias, and exposure of
patients and physicians to relatively high levels of
radiation.3-4 During the last decade, clinical
applications of the 3-dimensional (3D) mapping
system have enabled real-time display of the
ablation catheter in cardiac anatomy and led to an
increased rate of procedure success in difficult
cases.5-6
In this report, we present the successful catheter
ablation of atypical atrial flutter after open heart
surgery, using a 3D mapping system.
Case
In February of 2013, a 65-year-old man was
admitted to the Arrhythmia Center of Seoul
National University Hospital for the management
of incessant atrial flutter. His current medical
problems included hypertension and dyslipidemia.
His medical history was significant for aortic
valve-replacement surgery using a mechanical
valve in 2006. He was regularly followed at the
Cardiac Surgery Center and was taking warfarin,
hydrochlorothiazide, and a statin. He had started to
feel intermittent palpitations with chest pain after
surgery, and was diagnosed with atrial flutter at a
regional hospital. RFCA was performed at that
hospital in 2011, but the patient’s symptoms were
not improved because of failed ablation. His
palpitations were sustained despite the use of
antiarrhythmic agents such as beta-blockers or
amiodarone. In addition, he experienced sudden
syncope and was diagnosed with tachycardiabradycardia
syndrome by Holter monitoring in June
2012. Although his syncope resolved after
implantation of a permanent pacemaker, he
continued experiencing intermittent palpitations
despite an intensive regimen of antiarrhythmic
medications. Consequently, he visited our
Arrhythmia Clinic in January 2013.
At his visit, 12-lead ECG showed a regular
narrow-QRS tachycardia with 2:1 AV conduction
(Figure. 1). The heart rate was 139 bpm; blood
pressure, 109/78 mmHg. Echocardiography
confirmed a well-functioning mechanical aortic
valve with a normal transaortic pressure gradient
and normal cavity size. However, it also showed
global hypokinetics of the left ventricle, with
decreased systolic function and an ejection fraction
(EF) of 43%. Coronary CT angiography showed no
significant stenosis in the coronary arteries.
After the patient provided written informed
consent, he was transferred to the electrophysiology
laboratory while he was experiencing
tachycardia. Tachycardia cycle length was 226 ms.
Entrainment mapping showed that the difference
between the post-pacing interval (PPI) and
tachycardia cycle length was ＜50 ms at the lateral
wall of the tricuspid annulus and ＞80 ms at the
septal wall (Figure. 2).
Therefore, we concluded that
the origin of the circuit was the right atrial free
wall rather than the cavotricuspid isthmusdependent
reentry, and we performed electroanatomical
mapping using the CARTO® 3 system
(Biosene Webster, Diamond Bar, Co USA). The
activation map revealed that the tachycardia
circuit was the right atriotomy scar-related
reentry (Figure. 3). Ablation was performed at gaps
in the scar area and at the isthmus between the
scar and the tricuspid annulus using a Thermocool
SF irrigated catheter (Biosene Webster, Diamond
Bar, CA, USA) and RF energy with 20-25 W.
Tachycardia was terminated during ablation, and
bidirectional block was confirmed after ablation.
Discussion
Intra-atrial reentrant tachycardia related to
postoperative scar tissue often develops after open
heart surgery; this tachycardia is difficult to
manage and may result in significant postoperative
morbidity. In this case, the patient had right
atriotomy scar-related atypical atrial flutter, which
was easy to be misdiagnosed as typical atrial
flutter. The structural changes that occur after
open heart surgery can serve as substrates for
arrhythmias. Treatment of these types of
arrhythmias sometimes requires an unconventional
approach. Studies have reported that in patients
with a history of open heart surgery, atypical
arrhythmia can be successfully cured by catheter
ablation.7-8 Catheter ablation procedures guided by
3D-mapping systems may increase the ablation
success rate and improve patient outcomes.
Therefore, we concluded that
the origin of the circuit was the right atrial free
wall rather than the cavotricuspid isthmusdependent
reentry, and we performed electroanatomical
mapping using the CARTO® 3 system
(Biosene Webster, Diamond Bar, Co USA). The
activation map revealed that the tachycardia
circuit was the right atriotomy scar-related
reentry (Figure. 3). Ablation was performed at gaps
in the scar area and at the isthmus between the
scar and the tricuspid annulus using a Thermocool
SF irrigated catheter (Biosene Webster, Diamond
Bar, CA, USA) and RF energy with 20-25 W.
Tachycardia was terminated during ablation, and
bidirectional block was confirmed after ablation.
PDF Links
Full text via DOI 
Download Citation 
