The value of left ventricular strain-volume loops in predicting response to cardiac resynchronization therapy
Mengruo Zhu1,2, Haiyan Chen1, Zibire Fulati1
1Department of Echocardiography, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai Institute of Medical Imaging, 180 Fenglin Road, Shanghai, 200032, China.
Insights
Left ventricular strain-volume loops, assessed using 3D speckle tracking imaging, can predict cardiac resynchronization therapy response. Septal myocardial wasted work analysis improves patient selection for CRT.
Area of Science:
- Cardiology
- Medical Imaging
- Biomedical Engineering
Background:
- Three-dimensional speckle tracking imaging (3D STI) enables simultaneous assessment of left ventricular (LV) strain and volume.
- Cardiac resynchronization therapy (CRT) is a treatment for heart failure (HF).
Purpose of the Study:
- To explore the predictive value of LV strain-volume loops for CRT response.
- To assess the utility of strain-volume loop characteristics in HF patients undergoing CRT.
Main Methods:
- Forty HF patients and twenty healthy individuals underwent 3D echocardiography and 3D STI.
- LV global and segmental principal strain (PS) and volume were acquired and plotted to create PS-volume loops.
- Loop characteristics, including slope and R²-S/D coupling, were analyzed.
Main Results:
- HF patients exhibited lower slope and R²-S/D coupling than healthy subjects.
- In CRT responders, baseline Midseptal R²-S/D coupling was lower and Midlateral slope was higher compared to non-responders.
- Baseline Midseptal R²-S/D coupling (cut-off 0.55) independently predicted CRT response with 89% sensitivity and 77% specificity.
Conclusions:
- Strain-volume loop analysis provides valuable information for predicting CRT response.
- Assessing septal myocardial wasted work at baseline aids in selecting appropriate patients for CRT.
Background:
Three-dimensional (3D) speckle tracking imaging (STI) allows the simultaneous assessment of left ventricular (LV) strain and volume. We aim to explore the value of LV strain-volume loops in predicting response to cardiac resynchronization therapy (CRT).
Methods:
Forty heart failure (HF) patients scheduled for CRT and twenty healthy individuals were enrolled. All subjects received a 3D echocardiography and 3D STI analysis to acquire LV global and segmental principal strain (PS) and volume simultaneously. Values were plotted in a Cartesian system to construct PS-volume loop which was assessed using the two characteristics of the linear fitting curve: the slope and the coefficient of determination (R2-S/D coupling).
Results:
HF patients at baseline showed significantly lower slope and R2-S/D coupling of all PS-volume loops than healthy subjects. As for as comparing Segmental PS-Global volume loop at baseline, Midseptal R2-S/D coupling was lower and Midlateral slope was higher in CRT responders than in non-responders. For each individual, the abnormal segmental heterogeneity of Midseptal slope and R2-S/D coupling were lower than Midlateral was observed only in responders. At follow-up, significant improvements of the Midseptal slope and R2-S/D coupling were observed in responders. Midseptal R2-S/D coupling at baseline was an independent predictor of CRT response and the cut-off value of 0.55 was recommended with sensitivity of 89% and specificity of 77%.
Conclusions:
Analysis of strain-volume loops could provide unique information for predicting response to CRT. Assessment of septal myocardial wasted work at baseline is helpful to improve patient selection for CRT.
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