Address for correspondence:
Xi Li MD. PhD
Department of Cardiology, Wuhan Asia Heart Hospital
753 Jinghan Road, Wuhan, Hubei, China, 430000
Email:
magiclx1234@163.com
Jinlin Zhang MD. PhD
Department of Cardiology, Wuhan Asia Heart Hospital
753 Jinghan Road, Wuhan, Hubei, China, 430000
Email: zjl1974@yeah.net
Yanhong Chen MD. PhD
Department of Cardiology, Wuhan Asia Heart Hospital
753 Jinghan Road, Wuhan, Hubei, China, 430000
Email: sailorsdog@gmail.com
INTRODUCTION
Left atrial appendage (LAA) has been known as a source of focal atrial
tachycardias (AT)1, 2。Radio-frequency (RF) energy
based focal ablation of these arrhythmias was a common strategy in most
cases. However, catheter ablation in these foci remains challenging due
to the complexity of the LAA anatomy. Sometimes an epicardial approach
is an alternative when endocardial ablation of LAA
fails2. Cryo-balloon based LAA isolation may be
considered before epicardial access3。We report a
patient with focal atrial tachycardia originated in the tip of a LAA
ligation stump (he underwent a heart valve mitral bio-prostheses
replacement and had his LAA ligated during the operation years ago),
who, being refractory to focal RF ablation, received a LAA isolation
using a cryo-balloon which successfully terminated the tachycardia and
converted the patient to sinus rhythm.
Key words: atrial tachycardia; left atrial appendage stump;
cryo-ablation; anti-coagulation, Rhythmia system
Case description
A 70-year-old man presented with
recurrent drug-refractory atrial tachycardia, who had underwent Mitral
valve replacement, Tricuspid valvuloplasty, and ligation of the LAA
years ago. The 12-lead electrocardiography demonstrated long RP
tachycardia with a negative P wave in I and aVL, a positive P wave in
inferior leads and a positive P wave in V1 (Figure 1A ). The
coronary sinus mapping revealed a distal-to-proximal atrial activation
sequence during the AT (Figure 1B ). After trans-septal
puncture, an Orion basket catheter (64 electrodes of
0.4 mm2 area; 2.5 mm spacing) was placed into the left
atrium. Using a ultra-high
resolution mapping system, (Rhythmia ™ system), 16947 points
were achieved which revealed that
the earliest atrial activation was inside the tip of the LAA stump
(Figure 1C ). Angiographic revealed the LAA ligation stump
(Figure 1D ). Then, an irrigated tip 3.5 mm ablation catheter
(Thermocool SF, Biosense Webster, Diamond Bar, CA, USA) was introduced
to the earliest activation point (Figure 2 ). Unfortunately the
catheter mechanically terminated the tachycardia, and
the atrial tachycardia could not
be induced by programmed
stimulations. RF energy was given
under sinus rhythm with the energy of 10-15 W at the earliest activation
spot. However, we were not sure about the end point due to a failure to
induce the atrial tachycardia. We were also concerned about the
potential risk of pericardial tamponade of a fragile LAA stump wall
during ablation, so ablation time was limited. But the atrial
tachycardia recurred 2 days later.
A second mapping confirmed the tachycardia was originated from the same
foci. Concerning the difficulties
of focal ablation strategy, we decided to electrically isolate the whole
LAA stump using a second generation 28-mm cryo-balloon (CB2; Arctic
Front Advance, Medtronic, USA). After placing the inner lumen circular
map catheter (Achieve 15mm, Medtronic Inc., Minneapolis, USA) into the
LAA stump, the CB was inflated and the complete LAA occlusion was
confirmed using angiography.
During the CB ablation, the atrial
tachycardia terminated and the sinus rhythm was restored (Figure
3 ). After ablation, pacing was performed to verify the left atrial
appendage stump electrical isolation (Figure 3C ).The patient
was put on a continual oral anticoagulation after the procedure. Our
follow-up of 6 months confirmed no recurrence of the tachycardia, nor
any ischemic embolism.