Mechanical asynchrony or myocardial shortening as MRI predictors of response to biventricular pacing. Which is best?
Marcus J, Zwanenburg J, de Cock C, Kuijer J, Kamp O, van Dijk J, Gotte M, Hofman M, van Rossum A
VU University Medical Center
Background: To select responders to cardiac resynchronization therapy (CRT). Purpose: To investigate whether regional myocardial function should be characterized by mechanical asynchrony, or by instantaneous measures (differences in strain at one time). Methods: Using MRI myocardial tagging, asynchrony of circumferential shortening was measured in 12 heart failure patients. Further, instantaneous measures were: the coefficient of variation in end-systolic strain, the peak shortening reserve, and the septal strain at end systole. CRT was applied, and increase in dP/dtmax defined the response. Results: Only the instantaneous measures (but not asynchrony) predicted the response to CRT (P < 0.01).