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Quantifying the Role of Regional Dyssynchrony on Global Left Ventricular Performance

Lamia, B and Tanabe, M and Kim, HK and Johnson, L and Gorcsan, J and Pinsky, MR (2009) Quantifying the Role of Regional Dyssynchrony on Global Left Ventricular Performance. JACC: Cardiovascular Imaging, 2 (12). 1350 - 1356. ISSN 1936-878X

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Objectives: We hypothesize that left ventricular (LV) segmental dyssynchrony, quantified by paradoxical systolic wall thinning, determines changes in global LV performance in a model of canine right ventricular (RV) pacing-induced dyssynchrony and the response to cardiac resynchronization therapy (CRT). Background: Quantification of LV dyssynchrony is important to assess the impact of CRT. Methods: Seven pentobarbital-anesthetized open-chest dogs had LV pressure-volume relations and mid-LV short-axis echocardiographic speckle tracking radial strain imaging during right atrial (RA) pacing, RV pacing to simulate left bundle branch block, and CRT using RV pacing plus either LV free-wall (CRTfw) and apical (CRTa) pacing. The area under the segmental LV time-radial strain positive and negative curves defined global thickening and thinning, respectively. Dyssynchrony was defined as the maximum time difference between earliest and latest peak segmental positive strain among 6 radial sites. Results: RA pacing had minimal dyssynchrony (58 ± 40 ms). RV pacing induced both dyssynchrony (213 ± 67 ms, p < 0.05) and reduced LV stroke work (SW) (67 ± 51 mJ, p < 0.05). CRTfw and CRTa decreased dyssynchrony (116 ± 47 ms and 50 ± 34 ms, respectively, p < 0.05 vs. RV pacing), but only CRTa restored LV SW to RA pacing levels. RV pacing decreased global thickening (129 ± 87% · ms) compared with RA pacing (258 ± 133% · ms, p < 0.05), whereas CRTfw and CRTa restored regional thickening to RA pacing levels (194 ± 83% · ms and 230 ± 76% · ms, respectively). The sum of thickening and thinning during RV (230 ± 88% · ms vs. 258 ± 133% · ms, p < 0.05) correlated (r = 0.98) with RA thickening, suggesting that all the loss of LV function was due to thinning. Conclusions: Dyssynchrony causes proportional changes in regional LV wall thinning and global LV SW that were reversed by CRT, suggesting that dyssynchrony impairs LV systolic function by causing paradoxical regional wall thinning and that CRT effectiveness can be monitored by its reversal. Thus, monitoring paradoxical regional thinning reversal may be used to define CRT effectiveness. © 2009 American College of Cardiology Foundation.


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Item Type: Article
Status: Published
CreatorsEmailPitt UsernameORCID
Lamia, B
Tanabe, M
Kim, HKhyk11@pitt.eduHYK11
Johnson, L
Gorcsan, Jgorcsan@pitt.eduGORCSAN
Pinsky, MRpinsky@pitt.eduPINSKY0000-0001-6166-700X
Date: 1 December 2009
Date Type: Publication
Journal or Publication Title: JACC: Cardiovascular Imaging
Volume: 2
Number: 12
Page Range: 1350 - 1356
DOI or Unique Handle: 10.1016/j.jcmg.2009.07.012
Schools and Programs: School of Medicine > Critical Care Medicine
Refereed: Yes
ISSN: 1936-878X
PubMed Central ID: PMC2818995
PubMed ID: 20083067
Date Deposited: 07 Mar 2012 20:41
Last Modified: 30 Jan 2020 16:55


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