Abstract 2912: Circumferential, Radial and Longitudinal Strain Variations at Rest and During Dobutamine Infusion: Application of 2D Strain for Myocardial Ischemia Detection
Background: Routine evaluation of regional function by visual wall-motion assessment is unsatisfactory. Bidimensional (2D) strain has great promise to improve objective quantification of regional function abnormalities during stress echocardiography.
Objectives: To evaluate the role of circumferential, radial and longitudinal strains during dobutamine stress echocardiography in detecting myocardial ischemia.
Methods: 10 open-chest pigs were studied at baseline and at 4 stages of ischemia: mild and moderate LAD stenoses (non flow limiting stenosis (NFLS) at rest, but decreasing hyperemia by 30% and 50%, respectively), severe stenoses (flow limiting stenosis (FLS) at rest by 30% and 50%, respectively), at rest and during dobutamine infusion. Segmental left ventricular function was assessed by calculation of M-mode wall thickening, measurement of circumferential, radial, and longitudinal strains (CS,RS,LS) and was compared to sonomicrometry in the risk area (RA) and in a control area (CA).
Results: At baseline, the 3 components of strains were significantly increased from rest to dobutamine stages. At rest and compared to baseline, CS was significantly decreased in presence of 30%NFLS whereas LS was significantly decreased for 30%FLS and LS for 50%FLS (P = NS) in risk area (anterior and antero-septal walls). During dobutamine, CS was significantly decreased in presence of 30%NFLS and LS was decreased for 50%NFLS. RS and wall thickening were significantly reduced only for 50%FLS.
Conclusions: 2D strain analysis of regional myocardial function demonstrated marked differences in strain variations during myocardial ischemia from rest to dobutamine. Circumferential strain appears to be more sensitive than longitudinal or radial strain for ischemia detection.