Dyssynchrony indices to predict response to cardiac resynchronization therapy: a comprehensive prospective single-center study.
BACKGROUND
Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT.


RESULTS
Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption.


CONCLUSIONS
These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.
Miyazaki
Chinami
C
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minn 55905, USA.
Redfield
Margaret M
MM
Powell
Brian D
BD
Lin
Grace M
GM
Herges
Regina M
RM
Hodge
David O
DO
Olson
Lyle J
LJ
Hayes
David L
DL
Espinosa
Raul E
RE
Rea
Robert F
RF
Bruce
Charles J
CJ
Nelson
Susan M
SM
Miller
Fletcher A
FA
Oh
Jae K
JK
D000368:Aged; D019540:Area Under Curve; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D004452:Echocardiography / Q000379:methods*; D005080:Exercise Test; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D020257:Ventricular Remodeling / Q000502:physiology; D016138:Walking / Q000502:physiology