Magnetic resonance imaging and response to cardiac resynchronization therapy: relative merits of left ventricular dyssynchrony and scar tissue.
OBJECTIVE
To assess the relative value of a novel measure of left ventricular (LV) dyssynchrony derived from magnetic resonance imaging (MRI) and the extent of scar tissue for prediction of response to cardiac resynchronization therapy (CRT).


RESULTS
Thirty-five heart failure patients scheduled for CRT were included. Left ventricular dyssynchrony was defined as the standard deviation of 16 segment time-to-maximum radial wall thickness (SDt-16) obtained from a cine-set of short-axis slices. Delayed-enhanced MRI was performed for scar analysis. Echocardiography was used to determine response to CRT (reduction > or =15% in LV end-systolic volume 6 months after implantation). At follow-up, 21 patients (60%) were classified as responders. On MRI, SDt-16 was significantly higher in responders compared with non-responders (median 97 vs. 60 ms, P < 0.001), whereas the total extent of scar was larger in non-responders (median 35% vs. 3% in responders, P < 0.001). At the logistic regression analysis, SDt-16 was directly associated (OR = 6.3, 95% CI 3.1-9.9, P < 0.001) and the total extent of scar was inversely associated (OR = 0.52, 95% CI 0.43-0.87, P < 0.001) with response to CRT.


CONCLUSIONS
Magnetic resonance imaging offers the unique opportunity to assess LV dyssynchrony and scar extent in a single session. Both these parameters are important predictors of echocardiographic response to CRT.
Marsan
Nina Ajmone
NA
Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
Westenberg
Jos J M
JJ
Ypenburg
Claudia
C
van Bommel
Rutger J
RJ
Roes
Stijntje
S
Delgado
Victoria
V
Tops
Laurens F
LF
van der Geest
Rob J
RJ
Boersma
Eric
E
de Roos
Albert
A
Schalij
Martin J
MJ
Bax
Jeroen J
JJ
D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D009202:Cardiomyopathies / Q000473:pathology*; D002921:Cicatrix / Q000473:pathology*; D005260:Female; D006333:Heart Failure / Q000473:pathology / Q000628:therapy*; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*