Left ventricular torsion analysis using echocardiographic speckle tracking in a canine model of dyssynchrony and cardiac resynchronization therapy predicts global cardiac performance
© Lamia et al; licensee BioMed Central Ltd. 2009
Published: 13 March 2009
Left ventricular (LV) torsion is a primary mechanism used to eject blood during systole. We hypothesized that LV torsion is impaired during dyssynchronous contractions and restored with cardiac resynchronization therapy (CRT) in proportion to the degree that global LV performance improves.
Seven anesthetized open-chest dogs had high fidelity pressure and conductance volume catheters to assess LV performance. Basal and apical Grayscale echo images were recorded. Right atrial (RA) pacing served as the control. Right ventricular (RV) outflow tract pacing created a left bundle branch block (LBBB) to simulate dyssynchrony. Simultaneous RV–LV free wall and RV–LV apex pacing were modeled CRT (CRTfw and CRTa). Torsion was estimated as the difference between apical and basal rotation in degrees.
LV torsion, as quantified by speckle tracking echocardiography in an acute canine model, was reduced by dyssynchrony contraction and restored by CRT in proportion to the degree to which global measures of LV performance also improved. Thus, torsion and global LV performance are linked during synchronous, dyssynchronous contractions and CRT.
This article is published under license to BioMed Central Ltd.