Hemodynamic improvement in cardiac resynchronization does not require improvement in left ventricular rotation mechanics

Three-dimensional tagged MRI analysis

Hiroshi Ashikaga, Christophe Leclercq, Jiangxia Wang, David A Kass, Elliot R. McVeigh

Research output: Contribution to journalArticle

Abstract

Background-Earlier studies have yielded conflicting evidence on whether or not cardiac resynchronization therapy (CRT) improves left ventricular (LV) rotation mechanics. Methods and Results-In dogs with left bundle branch block and pacing-induced heart failure (n=7), we studied the effects of CRT on LV rotation mechanics in vivo by 3-dimensional tagged magnetic resonance imaging with a temporal resolution of 14 ms. CRT significantly improved hemodynamic parameters but did not significantly change the LV rotation or rotation rate. LV torsion, defined as LV rotation of each slice with respect to that of the most basal slice, was not significantly changed by CRT. CRT did not significantly change the LV torsion rate. There was no significant circumferential regional heterogeneity (anterior, lateral, inferior, and septal) in LV rotation mechanics in either left bundle branch block with pacing-induced heart failure or CRT, but there was significant apex-to-base regional heterogeneity. Conclusions-CRT acutely improves hemodynamic parameters without improving LV rotation mechanics. There is no significant circumferential regional heterogeneity of LV rotation mechanics in the mechanically dyssynchronous heart. These results suggest that LV rotation mechanics is an index of global LV function, which requires coordination of all regions of the left ventricle, and improvement in LV rotation mechanics appears to be a specific but insensitive index of acute hemodynamic response to CRT.

Original languageEnglish (US)
Pages (from-to)456-463
Number of pages8
JournalCirculation: Cardiovascular Imaging
Volume3
Issue number4
DOIs
StatePublished - Jul 2010

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Cardiac Resynchronization Therapy
Mechanics
Hemodynamics
Bundle-Branch Block
Heart Failure
Left Ventricular Function
Heart Ventricles
Magnetic Resonance Imaging
Dogs

Keywords

  • Mechanics
  • MRI
  • Tagging
  • Torsional deformation
  • Ventricular function

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Radiology Nuclear Medicine and imaging
  • Medicine(all)

Cite this

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title = "Hemodynamic improvement in cardiac resynchronization does not require improvement in left ventricular rotation mechanics: Three-dimensional tagged MRI analysis",
abstract = "Background-Earlier studies have yielded conflicting evidence on whether or not cardiac resynchronization therapy (CRT) improves left ventricular (LV) rotation mechanics. Methods and Results-In dogs with left bundle branch block and pacing-induced heart failure (n=7), we studied the effects of CRT on LV rotation mechanics in vivo by 3-dimensional tagged magnetic resonance imaging with a temporal resolution of 14 ms. CRT significantly improved hemodynamic parameters but did not significantly change the LV rotation or rotation rate. LV torsion, defined as LV rotation of each slice with respect to that of the most basal slice, was not significantly changed by CRT. CRT did not significantly change the LV torsion rate. There was no significant circumferential regional heterogeneity (anterior, lateral, inferior, and septal) in LV rotation mechanics in either left bundle branch block with pacing-induced heart failure or CRT, but there was significant apex-to-base regional heterogeneity. Conclusions-CRT acutely improves hemodynamic parameters without improving LV rotation mechanics. There is no significant circumferential regional heterogeneity of LV rotation mechanics in the mechanically dyssynchronous heart. These results suggest that LV rotation mechanics is an index of global LV function, which requires coordination of all regions of the left ventricle, and improvement in LV rotation mechanics appears to be a specific but insensitive index of acute hemodynamic response to CRT.",
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AU - Leclercq, Christophe

AU - Wang, Jiangxia

AU - Kass, David A

AU - McVeigh, Elliot R.

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N2 - Background-Earlier studies have yielded conflicting evidence on whether or not cardiac resynchronization therapy (CRT) improves left ventricular (LV) rotation mechanics. Methods and Results-In dogs with left bundle branch block and pacing-induced heart failure (n=7), we studied the effects of CRT on LV rotation mechanics in vivo by 3-dimensional tagged magnetic resonance imaging with a temporal resolution of 14 ms. CRT significantly improved hemodynamic parameters but did not significantly change the LV rotation or rotation rate. LV torsion, defined as LV rotation of each slice with respect to that of the most basal slice, was not significantly changed by CRT. CRT did not significantly change the LV torsion rate. There was no significant circumferential regional heterogeneity (anterior, lateral, inferior, and septal) in LV rotation mechanics in either left bundle branch block with pacing-induced heart failure or CRT, but there was significant apex-to-base regional heterogeneity. Conclusions-CRT acutely improves hemodynamic parameters without improving LV rotation mechanics. There is no significant circumferential regional heterogeneity of LV rotation mechanics in the mechanically dyssynchronous heart. These results suggest that LV rotation mechanics is an index of global LV function, which requires coordination of all regions of the left ventricle, and improvement in LV rotation mechanics appears to be a specific but insensitive index of acute hemodynamic response to CRT.

AB - Background-Earlier studies have yielded conflicting evidence on whether or not cardiac resynchronization therapy (CRT) improves left ventricular (LV) rotation mechanics. Methods and Results-In dogs with left bundle branch block and pacing-induced heart failure (n=7), we studied the effects of CRT on LV rotation mechanics in vivo by 3-dimensional tagged magnetic resonance imaging with a temporal resolution of 14 ms. CRT significantly improved hemodynamic parameters but did not significantly change the LV rotation or rotation rate. LV torsion, defined as LV rotation of each slice with respect to that of the most basal slice, was not significantly changed by CRT. CRT did not significantly change the LV torsion rate. There was no significant circumferential regional heterogeneity (anterior, lateral, inferior, and septal) in LV rotation mechanics in either left bundle branch block with pacing-induced heart failure or CRT, but there was significant apex-to-base regional heterogeneity. Conclusions-CRT acutely improves hemodynamic parameters without improving LV rotation mechanics. There is no significant circumferential regional heterogeneity of LV rotation mechanics in the mechanically dyssynchronous heart. These results suggest that LV rotation mechanics is an index of global LV function, which requires coordination of all regions of the left ventricle, and improvement in LV rotation mechanics appears to be a specific but insensitive index of acute hemodynamic response to CRT.

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