Mapping and ablation of the pulmonary veins and cavo-tricuspid isthmus with a magnetic resonance imaging-compatible externally irrigated ablation catheter and integrated electrophysiology system.
BACKGROUND
Magnetic resonance imaging (MRI)-guided interventional electrophysiology (EP) has rapidly emerged as a promising alternative to x-ray-guided ablation. We aimed to evaluate an externally irrigated MRI-compatible ablation catheter and integrated EP pacing and recording system, testing the feasibility of pulmonary vein and cavo-tricuspid isthmus ablation.


RESULTS
Externally irrigated MRI-compatible ablation and diagnostic EP catheters and an integrated EP recording system (Imricor Medical Systems, Burnsville, MN) were tested in n=11 sheep in a 1.5-T MRI scanner. Power-controlled (40 W, 120-second duration) lesions were formed at the pulmonary vein and cavo-tricuspid isthmus. Real-time intracardiac electrograms were recorded during MRI. Steady-state free precession non-breath-hold images were repeatedly acquired to guide catheter navigation. Lesion visualization was performed using noncontrast (T2-weighted turbo spin echo pulse sequence) and gadolinium-diethylene triamine pentaacetic acid-enhanced T1-weighted imaging (inversion-recovery gradient echo pulse sequence). Catheters were able to be visualized and navigated under cardiovascular magnetic resonance guidance. In total, 8±2.5 lesions (radiofrequency time, 16±4.2 minutes) were formed at the pulmonary vein ostia, and 6.5±1.3 lesions (radiofrequency time, 13±2.2 minutes) were formed at the cavo-tricuspid isthmus, with the end point of bidirectional block. The mean procedure time was 150±55 minutes. Lesion visualization with both T2W imaging and contrast-enhanced imaging correlated with sites of injury at autopsy.


CONCLUSIONS
These data demonstrate the feasibility of using multiple catheters, an integrated EP pacing and recording system, and externally irrigated ablation with cardiovascular magnetic resonance guidance to undertake clinically relevant biatrial mapping and ablation.
Centre for Heart Rhythm Disorders, University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia.
Anand N
AN
Ganesan
Joseph B
JB
Selvanayagam
Rajiv
R
Mahajan
Suchi
S
Grover
Sachin
S
Nayyar
Anthony G
AG
Brooks
John
J
Finnie
Daniel
D
Sunnarborg
Thomas
T
Lloyd
Adhiraj
A
Chakrabarty
Hany S
HS
Abed
Prashanthan
P
Sanders
D000818:Animals; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D004867:Equipment Design; D005240:Feasibility Studies; D005682:Gadolinium; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D023421:Models, Animal; D011667:Pulmonary Veins / Q000473:pathology* / Q000601:surgery*; D012756:Sheep; D014261:Tricuspid Valve / Q000473:pathology* / Q000601:surgery*
D005682:Gadolinium