Practical and conceptual limitations of tissue Doppler imaging to predict reverse remodelling in cardiac resynchronisation therapy

Abstract

Background: Recent, conflicting results about the use of tissue Doppler imaging derived (TDI-) asynchrony indices to predict reverse remodelling after cardiac resynchronisation therapy (CRT) have raised questions about their physiological meaning and methodological limitations. Methods: In 41 patients, baseline TDI-derived septal to lateral delays of peak velocities (TDI-SL), standard deviation of peak velocities over 12 segments (Ts-SD), and peak 2D longitudinal strain (strain-SL) were compared with volumetric response (reduction in end-systolic volume of ≥ 15%) after at least 6 months of CRT. Timing of peak TDI velocities was compared to timing of 2DS velocities and strain-SL. Influence of sample position, transverse motion, and interobserver inconsistency of the chosen peak velocities was assessed. Diagnostic accuracy of TDI-based delays was compared to accuracy of visual and 2D strain-based assessment. Results: After 7.0 ± 3.2 months of CRT, 24 patients were classified as responders. TDI-SL and Ts-SD were similar between responders and nonresponders at baseline, did not predict response, and were unaffected by CRT. Visual asynchrony scoring and strain-SL were better predictors of response than TDI-SL and Ts-SD. TDI measurements were highly susceptible to sample location and transverse motion components and poorly correlated with the timing of longitudinal contraction. There was a considerably poor agreement between observers with regard to scoring of TDI-SL and Ts-SD. Conclusion: TDI-based measurements of asynchrony do not appear robust predictors of volume response to CRT.

Cardiac Resynchronization Therapy

“…Myocardial velocities, measured with tissue Doppler imaging, are increasingly recognized as unreliable, because velocity does not imply active myocardial shortening and because misalignment of the ultrasound beam with the myocardial wall provides erroneous information. 35 Also, the multiple shortening peaks, especially in the septum of LBBB hearts, may create a definition problem between investigators quantifying dyssynchrony. In this regard it is relevant that analysis of all echocardiograms by a core lab did result in a significant prediction of the likelihood of death, transplantation, or LVAD implantation by CRT.…”

The CRT Monopoly Game

“…This can create considerable errors. 6 Moreover, common definitions in echocardiography may be flawed for determining mechanical dyssynchrony in LBBB hearts. In LBBB, the septum shows a very early start of contraction, evidenced by leftward septal motion and strain and strain rate (Figure).…”

How to Define Cardiac Resynchronization Therapy Response

“…Severely remodeled LV can be ''beyond repair,'' and these patients are less likely to respond to CRT. 25 Two predictors of adverse remodeling and poorer clinical outcomes are severe LV dilatation and MR. 26,27 Non-ischemic patients generally have better outcomes compared to ischemic patients. Regarding atrial fibrillation in HF, approximately 25% of patients with HF and up to 50% of patients with class IV HF will have atrial fibrillation.…”