Novel technique for cardiac electromechanical mapping with magnetic resonance imaging tagging and an epicardial electrode sock.
Near-simultaneous measurements of electrical and mechanical activation over the entire ventricular surface are now possible using magnetic resonance imaging tagging and a multielectrode epicardial sock. This new electromechanical mapping technique is demonstrated in the ventricularly paced canine heart. A 128-electrode epicardial sock and pacing electrodes were placed on the hearts of four anesthetized dogs. In the magnetic resonance scanner, tagged cine images (8-15 ms/frame) and sock electrode recordings (1000 Hz) were acquired under right-ventricular pacing and temporally referenced to the pacing stimulus. Electrical recordings were obtained during intermittent breaks in image acquisition, so that both data sets represented the same physiologic state. Since the electrodes were not visible in the images, electrode recordings and cine images were spatially registered with Gd-DTPA markers attached to the sock. Circumferential strain was calculated at locations corresponding to electrodes. For each electrode location, electrical and mechanical activation times were calculated and relationships between the two activation patterns were demonstrated. This method holds promise for improving understanding of the relationships between the patterns of electrical activation and contraction in the heart.
Faris
Owen P
OP
Laboratory of Cardiac Energetics, National Institutes of Health, NHLBI, 10 Center Drive, Room B1D416, Bethesda, MD 20892, USA. fariso@nih.gov
Evans
Frank J
FJ
Ennis
Daniel B
DB
Helm
Patrick A
PA
Taylor
Joni L
JL
Chesnick
A Scott
AS
Guttman
Michael A
MA
Ozturk
Cengizhan
C
McVeigh
Elliot R
ER
D000818:Animals; D018780:Body Surface Potential Mapping / Q000295:instrumentation / Q000379:methods*; D002304:Cardiac Pacing, Artificial / Q000379:methods; D004285:Dogs; D004548:Elasticity; D004562:Electrocardiography / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D005240:Feasibility Studies; D006352:Heart Ventricles / Q000033:anatomy & histology; D007089:Image Enhancement / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D009068:Movement / Q000502:physiology; D010496:Pericardium / Q000033:anatomy & histology / Q000502:physiology; D013314:Stress, Mechanical; D013382:Subtraction Technique; D016276:Ventricular Function; D016278:Ventricular Function, Right / Q000502:physiology*