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.
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.
Authors: Anja Lutz; Jan Paul; Axel Bornstedt; G Ulrich Nienhaus; Patrick Etyngier; Peter Bernhardt; Wolfgang Rottbauer; Volker Rasche Journal: J Cardiovasc Magn Reson Date: 2012-10-26 Impact factor: 5.364
Authors: Louis S Fixsen; Niels J Petterson; Patrick Houthuizen; Marcel C M Rutten; Frans N van de Vosse; Richard G P Lopata Journal: Artif Organs Date: 2020-04-18 Impact factor: 3.094