Interventricular mechanical dyssynchrony: quantification with velocity-encoded MR imaging.
OBJECTIVE
To evaluate the performance of velocity-encoded (VENC) magnetic resonance (MR) imaging, as compared with pulsed-wave echocardiography (PW-ECHO), in the quantification of interventricular mechanical dyssynchrony (IVMD) as a predictor of response to cardiac resynchronization therapy (CRT).


METHODS
The study was approved by the local ethics committee, and all patients provided written informed consent. The study involved the examination of 45 patients (nine women, 36 men; median age, 60 years; interquartile age range, 47-69 years) with New York Heart Association class 2.0-3.0 heart failure and a reduced left ventricular ejection fraction (median, 25%; interquartile range, 21%-32%), with (n = 25) or without (n = 20) left bundle branch block. Aortic and pulmonary flow curves were constructed by using VENC MR imaging and PW-ECHO. IVMD was defined as the difference between the onset of aortic flow and the onset of pulmonary flow. Intraclass correlation coefficient, Spearman correlation coefficient, Bland-Altman, and Cohen kappa analyses were used to assess agreement between observers and methods.


RESULTS
Inter- and intraobserver agreement regarding VENC MR imaging IVMD measurements was very good (intraclass r = 0.96, P < .001; mean bias, -3 msec +/- 11 [standard deviation] and 0 msec +/- 10, respectively). A strong correlation (Spearman r = 0.92, P < .001) and strong agreement (mean difference, -6 msec +/- 16) were found between VENC MR imaging and PW-ECHO in the quantification of IVMD. Agreement between VENC MR imaging and PW-ECHO in the identification of potential responders to CRT was excellent (Cohen kappa = 0.94).


CONCLUSIONS
VENC MR measurements of IVMD are equivalent to PW-ECHO measurements and can be used to identify potential responders to CRT.
Muellerleile
Kai
K
Center for Cardiology and Cardiovascular Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany. ka.muellerleile@uke.de
Baholli
Loant
L
Groth
Michael
M
Barmeyer
Achim A
AA
Koopmann
Katharina
K
Ventura
Rodolfo
R
Koester
Ralf
R
Adam
Gerhard
G
Willems
Stephan
S
Lund
Gunnar K
GK
D000368:Aged; D001021:Aortic Valve; D001783:Blood Flow Velocity; D002304:Cardiac Pacing, Artificial; D004452:Echocardiography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011664:Pulmonary Valve; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000628:therapy