Cardiac dyssynchrony quantitated by time-to-peak or temporal uniformity of strain at longitudinal, circumferential, and radial level: implications for resynchronization therapy

Benedetta Bertola; Elisa Rondano; Marina Sulis; Gianni Sarasso; Cristina Piccinino; Giuliano Marti; Paolo Devecchi; Andrea Magnani; Gabriella Francalacci; Paolo N Marino

doi:10.1016/j.echo.2009.03.010

Cardiac dyssynchrony quantitated by time-to-peak or temporal uniformity of strain at longitudinal, circumferential, and radial level: implications for resynchronization therapy

J Am Soc Echocardiogr. 2009 Jun;22(6):665-71. doi: 10.1016/j.echo.2009.03.010. Epub 2009 May 7.

Authors

Benedetta Bertola¹, Elisa Rondano, Marina Sulis, Gianni Sarasso, Cristina Piccinino, Giuliano Marti, Paolo Devecchi, Andrea Magnani, Gabriella Francalacci, Paolo N Marino

Affiliation

¹ Clinical Cardiology, University of Eastern Piedmont, Azienda Ospedaliera Universitaria Maggiore della Carità, Corso Mazzini 18, 28100 Novara, Italy.

PMID: 19423288
DOI: 10.1016/j.echo.2009.03.010

Abstract

Background: The standard deviation of time to peak strain (TPS-SD) has been proposed as an index of left ventricular (LV) dyssynchrony in patients to be resynchronized. However, TPS-SD is sensitive to noise, and the influence of outliers on TPS-SD is also relevant. Alternatively, dyssynchrony can be indexed by temporal uniformity of strain (TUS), whereby a time plot of regional strains, arranged for LV location, is subjected to Fourier analysis. If segments shorten simultaneously (synchronously), the plot appears as a straight line, with power only in the zero-order Fourier term, whereas regionally clustered dyssynchrony generates an undulating plot with higher power in the first-order term. TUS index reflects zero-order relative to first-order plus zero-order power.

Methods: In this study, TUS and TPS-SD were computed in 68 patients (QRS duration >/= 120 ms; ejection fraction </= 0.35) in whom longitudinal, circumferential, and radial strains were measured using speckle-tracking two-dimensional echocardiography before and 3 to 6 months after cardiac resynchronization therapy (CRT), together with LV volumes.

Results: Following CRT, LV volume decreased (diastolic, -10 +/- 20%) and ejection fraction improved from 0.23 +/- 0.07% to 0.30 +/- 0.10% (P < .001 for both). Circumferential strain was ameliorated as well (P = .054). Two-way analysis of variance revealed TUS improvement after CRT (P = .043), with a trend for CRT to contrast asynchrony at the circumferential (+0.06 +/- 0.25) and longitudinal (+0.05 +/- 0.18) levels compared with the radial level (-0.002 +/- 0.18) (interaction P = .06). This was not true for TPS-SD. Multivariate analysis revealed that only TUS, assessed before CRT circumferentially, predicted ejection fraction improvement after CRT. Other asynchrony variables failed in the model.

Conclusion: Dyssynchrony indexed by circumferential TUS yields greater CRT benefits than that indexed by TPS-SD, supporting the idea of targeting TUS-measured dyssynchrony as a more informative quantitative measurement in CRT patients.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aged
Algorithms*
Cardiac Pacing, Artificial / methods*
Echocardiography, Doppler / methods*
Elasticity Imaging Techniques / methods*
Female
Humans
Image Enhancement / methods
Image Interpretation, Computer-Assisted / methods*
Male
Middle Aged
Prognosis
Regression Analysis
Reproducibility of Results
Retrospective Studies
Sensitivity and Specificity
Treatment Outcome
Ventricular Dysfunction, Left / diagnostic imaging*
Ventricular Dysfunction, Left / prevention & control*