Mitral isthmus ablation with and without temporary spot occlusion of the coronary sinus: a randomized clinical comparison of acute outcomes.
OBJECTIVE
To evaluate the safety and outcomes of mitral isthmus (MI) linear ablation with temporary spot occlusion of the coronary sinus (CS).


BACKGROUND
CS blood flow cools local tissue precluding transmurality and bidirectional block across MI lesion.


METHODS
In a randomized, controlled trial (CS-occlusion = 20, Control = 22), MI ablation was performed during continuous CS pacing to monitor the moment of block. CS was occluded at the ablation site using 1 cm spherical balloon, Swan-Ganz catheter with angiographic confirmation. Ablation was started at posterior mitral annulus and continued up to left inferior pulmonary vein (LIPV) ostium using an irrigated-tip catheter. If block was achieved, balloon was deflated and linear block confirmed. If not, additional ablation was performed epicardially (power ≤25 W). Ablation was abandoned after ∼30 minutes, if block was not achieved.


RESULTS
CS occlusion (mean duration -27 ± 9 minutes) was achieved in all cases. Complete MI block was achieved in 13/20 (65%) and 15/22 (68%) patients in the CS-occlusion and control arms, respectively, P = 0.76. Block was achieved with significantly small number (0.5 ± 0.8 vs 1.9 ± 1.1, P = 0.0008) and duration (1.2 ± 1.7 vs 4.2 ± 3.5 minutes, P = 0.009) of epicardial radiofrequency (RF) applications and significantly lower amount of epicardial energy (1.3 ± 2.4 vs 6.3 ± 5.7 kJ, P = 0.006) in the CS-occlusion versus control arm, respectively. There was no difference in total RF (22 ± 9 vs 23 ± 11 minutes, P = 0.76), procedural (36 ± 16 vs 39 ± 20 minutes, P = 0.57), and fluoroscopic (13 ± 7 vs 15 ± 10 minutes, P = 0.46) durations for MI ablation between the 2 arms. Clinically uneventful CS dissection occurred in 1 patient


CONCLUSIONS
Temporary spot occlusion of CS is safe and significantly reduces the requirement of epicardial ablation to achieve MI block. It does not improve overall procedural success rate and procedural duration. Tissue cooling by CS blood flow is just one of the several challenges in MI ablation.
Hôpital Cardiologique du Haut Lévêque Université Victor Segalen Bordeaux II, Bordeaux, Pessac, France. meleze.hocini@chu-bordeaux.fr
Mélèze
M
Hocini
Ashok J
AJ
Shah
Isabelle
I
Nault
Lena
L
Rivard
Nick
N
Linton
Sanjiv
S
Narayan
Shinsuke
S
Myiazaki
Amir S
AS
Jadidi
Sébastien
S
Knecht
Daniel
D
Scherr
Stephen B
SB
Wilton
Laurent
L
Roten
Patrizio
P
Pascale
Michala
M
Pedersen
Nicolas
N
Derval
Frédéric
F
Sacher
Pierre
P
Jaïs
Jacques
J
Clémenty
Michel
M
Haïssaguerre
D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D021721:Balloon Occlusion / Q000009:adverse effects; D017115:Catheter Ablation / Q000009:adverse effects; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D054326:Coronary Sinus / Q000000981:diagnostic imaging; D022062:Electrophysiologic Techniques, Cardiac; D005240:Feasibility Studies; D005260:Female; D005602:France; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome