Regional and global strain changes during biventricular pacing in a porcine model of acute left ventricular volume overload.


Journal Article

OBJECTIVES:Biventricular pacing may ameliorate symptoms of acute heart failure. Speckle-tracking echocardiography can assess cardiac function to elucidate mechanisms of benefit. Accordingly, radial and circumferential strain and radial and circumferential strain synchrony were measured with speckle-tracking echocardiography during biventricular pacing in a model of left ventricular (LV) volume overload. METHODS:Heart block was established in 4 open-chest anesthetized pigs. Left ventricular volume overload was induced with an ascending aorta-LV apex conduit. Measurements included cardiac output by an aortic flow probe, the maximum derivative of LV pressure versus time (dP/dtmax), and transseptal pressure synchrony. Biventricular pacing was performed for combinations of 3 interventricular delays and 3 LV pacing sites. Speckle-tracking echocardiographic analysis was applied to short-axis images at the midpapillary LV for 9 pacing combinations. Strain and synchrony parameters were correlated with hemodynamics. RESULTS:Increased cardiac output correlated with improved global circumferential strain (P = .002) but not changes in global radial strain or radial strain synchrony. Increased LV dP/dtmax was associated with improved circumferential strain in the septum (P < .001) and radial strain in the lateral wall (P = .046). Improved transseptal pressure synchrony was associated with improved global circumferential strain, but primarily in the septum (P < .001). Aortic valve closure occurred before peak radial strain in 62% of beats and before peak circumferential strain in 6%. CONCLUSIONS:During acute LV volume overload, hemodynamic improvement with biventricular pacing was associated with improved circumferential strain primarily in the septum. Radial strain and radial strain synchrony did not correlate with improvement, possibly due to delayed systolic contraction. An increase in circumferential strain in the septum associated with optimum transseptal pressure synchrony suggested improvement by interventricular assist from the right ventricle.

Full Text

Cited Authors

  • Wang, A; Cabreriza, SE; Quinn, TA; Richmond, ME; Cheng, B; Spotnitz, HM

Published Date

  • April 2013

Published In

Volume / Issue

  • 32 / 4

Start / End Page

  • 675 - 682

PubMed ID

  • 23525394

Pubmed Central ID

  • 23525394

Electronic International Standard Serial Number (EISSN)

  • 1550-9613

International Standard Serial Number (ISSN)

  • 0278-4297

Digital Object Identifier (DOI)

  • 10.7863/jum.2013.32.4.675


  • eng