Electroanatomic mapping of the left ventricle in a porcine model of chronic myocardial infarction with magnetic resonance-based catheter tracking.
BACKGROUND
X-ray fluoroscopy constitutes the fundamental imaging modality for catheter visualization during interventional electrophysiology procedures. The minimal tissue discriminative capability of fluoroscopy is mitigated in part by the use of electroanatomic mapping systems and enhanced by the integration of preacquired 3-dimensional imaging of the heart with computed tomographic or magnetic resonance (MR) imaging. A more ideal paradigm might be to use intraprocedural MR imaging to directly image and guide catheter mapping procedures.


RESULTS
An MR imaging-based electroanatomic mapping system was designed to assess the feasibility of navigating catheters to the left ventricle in vivo using MR tracking of microcoils incorporated into the catheters, measuring intracardiac ventricular electrograms, and integrating this information with 3-dimensional MR angiography and myocardial delayed enhancement images to allow ventricular substrate mapping. In all animals (4 normal, and 10 chronically infarcted swine), after transseptal puncture under fluoroscopic guidance, catheters were successfully navigated to the left ventricle with MR tracking (13 to 15 frames per second) by both transseptal and retrograde aortic approaches. Electrogram artifacts related to the MR imaging gradient pulses were successfully removed with analog and digital signal processing. In all animals, it was possible to map the entire left ventricle and to project electrogram voltage amplitude maps to identify the scarred myocardium.


CONCLUSIONS
It is possible to use MR tracking to navigate catheters to the left ventricle, to measure electrogram activity, and to render accurate 3-dimensional voltage maps in a porcine model of chronic myocardial infarction, completely in the MR imaging environment. Myocardial delayed enhancement guidance provided dense sampling of the proximity of the infarct and accurate localization of complex infarcts.
Dukkipati
Srinivas R
SR
Cardiac Arrhythmia Service, Massachusetts General Hospital and Harvard Medical School, Boston, Mass., USA.
Mallozzi
Richard
R
Schmidt
Ehud J
EJ
Holmvang
Godtfred
G
d'Avila
Andre
A
Guhde
Renee
R
Darrow
Robert D
RD
Slavin
Glenn
G
Fung
Maggie
M
Malchano
Zachary
Z
Kampa
Greg
G
Dando
Jeremy D
JD
McPherson
Christina
C
Foo
Thomas K
TK
Ruskin
Jeremy N
JN
Dumoulin
Charles L
CL
Reddy
Vivek Y
VY
D000818:Animals; D017115:Catheter Ablation / Q000379:methods; D002404:Catheterization / Q000009:adverse effects / Q000379:methods; D004195:Disease Models, Animal; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology*; D008012:Lidocaine / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D013552:Swine; D017180:Tachycardia, Ventricular / Q000209:etiology / Q000517:prevention & control
D008012:Lidocaine