Intraoperative characterization of interventricular mechanical dyssynchrony using electroanatomic mapping system--a feasibility study.
BACKGROUND
Interventricular mechanical dyssynchrony (VVMD) is a strong predictor of cardiac resynchronization therapy (CRT) response. However, no simple and reliable clinical method of measuring VVMD during CRT implant is currently available. We tested the hypothesis that the EnSite™ NavX™ system (St. Jude Medical, St. Paul, MN, USA) can be used intraoperatively to determine VVMD, thereby facilitating CRT optimization.


METHODS
During CRT implant, the leads in the right atrium (RA), right ventricle (RV), and left ventricle (LV) were connected to the EnSite™ NavX™ system to record the real-time 3D motion of the lead electrodes. The distances from RA to RV lead electrodes (RA-RV) and RA to LV lead electrodes (RA-LV) were computed over ten cardiac cycles during each of RV pacing and biventricular (BiV) pacing, respectively. The degree of synchrony was computed from the distance waveforms between RA-RV and RA-LV by a cross-covariance method to characterize VVMD. Septal-to-posterior wall motion delay (SPWMD) from M-mode echocardiography (echo) was measured for reference at each pacing intervention. VVMD was present in all five patients undergoing CRT implant.


RESULTS
Four of the five patients demonstrated clear improvement in EnSite™ NavX™-derived VVMD during BiV versus RV pacing, which corresponded to the SPWMD results by echo.


CONCLUSIONS
It is feasible to characterize VVMD and resynchronization in CRT patients with the EnSite™ NavX™ system during implant, demonstrating its potential as a tool for intraoperative CRT optimization.
Kerckhoff Heart Center, Bad Nauheim, Germany. j.sperzel@kerckhoff-klinik.de
Johannes
J
Sperzel
Roland
R
Brandt
Wenbo
W
Hou
Annette
A
Doelger
Jan
J
Zdarek
Stuart P
SP
Rosenberg
Kyungmoo
K
Ryu
Steve
S
Koh
Michael
M
Yang
D000368:Aged; D058406:Cardiac Resynchronization Therapy; D009202:Cardiomyopathies / Q000503:physiopathology* / Q000601:surgery*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation*; D005240:Feasibility Studies; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D007432:Intraoperative Period; D008297:Male