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Novel algorithm for quantitative assessment of left ventricular dyssynchrony with ECG-gated myocardial perfusion
Keisuke Kiso1, Akira Imoto, Yoshihiro Nishimura
1Department of Radiology and Nuclear Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan. kkeisuke@hsp.ncvc.go.jp
Insights
A new algorithm using ECG-gated myocardial perfusion SPECT (GMPS) accurately assesses left ventricular (LV) dyssynchrony. This method predicts and evaluates response to cardiac resynchronization therapy (CRT) in heart failure patients.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Medical Imaging
Background:
- Cardiac resynchronization therapy (CRT) is a key treatment for severe heart failure.
- Left ventricular (LV) dyssynchrony is a critical predictor of CRT response.
- Accurate assessment of LV dyssynchrony is essential for optimizing CRT management.
Purpose of the Study:
- To develop and evaluate a novel software algorithm for quantitative assessment of LV dyssynchrony.
- To utilize ECG-gated myocardial perfusion SPECT (GMPS) for LV dyssynchrony measurement.
- To assess the utility of this new method in predicting and managing CRT response.
Main Methods:
- Thirty-three patients with chronic severe heart failure underwent GMPS before and 6 months after CRT.
- A new algorithm calculated LV dyssynchrony index (DI) based on time to end-systole (TES) from GMPS data.
- DI was compared with echocardiographic LV dyssynchrony (ΔTPV) and correlated with LV function parameters (LVEF, LVESV).
Main Results:
- Baseline DI significantly correlated with LV ejection fraction (LVEF) and LV end-systolic volume (LVESV).
- Patients responding to CRT (R-Gp) exhibited significantly higher baseline DI than non-responders (NR-Gp).
- In responders, DI significantly decreased post-CRT, and baseline DI correlated with tissue Doppler imaging (TDI) ΔTPV.
Conclusions:
- The developed GMPS-based algorithm provides a reliable estimation of LV dyssynchrony.
- This method demonstrates comparability to tissue Doppler imaging (TDI) for dyssynchrony assessment.
- The algorithm aids in predicting and evaluating the effectiveness of cardiac resynchronization therapy.
Objectives:
Cardiac resynchronization therapy (CRT) is the established treatment for patients with chronic and severe heart failure, and it has been reported that the presence of left ventricular (LV) dyssynchrony is one of the most important factors which predict positive response of this therapy. In the present study, we developed new software algorithm for quantitative assessment of LV dyssynchrony from ECG-gated myocardial perfusion SPECT (GMPS), and evaluated its utility for the management of CRT.
Methods:
Thirty-three patients with chronic severe heart failure were studied. GMPS was performed with 16 frame per-cardiac-cycle before and 6 months after CRT and LV end-diastolic volume, end-systolic volume (LVESV), ejection fraction (LVEF) were calculated by QGS software. We generated the time-activity curve per-cardiac-cycle in 4 myocardial segments by Fourier transform curve-fitting of the 16 serial count values, and measured the time from R-wave to the maximum-count point [time to end-systole (TES)] in each. For the evaluation of the degree of LV dyssynchrony, we used the maximum difference in TES (ΔTES) among the 4 segments which corrected for R-R time as dyssynchrony index (DI). Moreover, DI at baseline evaluated by GMPS was compared with the echocardiographic index of LV dyssynchrony; maximum difference of time to peak velocity (ΔTPV) evaluated by tissue Doppler imaging (TDI).
Results:
DI before CRT showed a significant correlation with the LV function, such as LVEF, LVESV (DI vs. LVEF; r = 0.57, P < 0.0001. DI vs. LVESV; r = 0.64, P < 0.0001). The study subjects were divided into 2 groups, responder group (R-Gp) with LVEF increase >10% or LVESV decrease >10% and non-responder group (NR-Gp). DI before CRT was significantly larger in R-Gp than in NR-Gp (25.9 ± 22.2 vs. 10.8 ± 8.9, P = 0.01). In R-Gp, DI showed a significant decrease after CRT (25.9 ± 22.2 → 13.6 ± 10.9, P < 0.05). DI at baseline measured by GMPS correlated significantly with ΔTPV at baseline measured by TDI (r = 0.38, P < 0.05).
Conclusions:
This new algorithm for the estimation of LV dyssynchrony might be comparable to TDI, and contributes to the prediction and the evaluation for the response of CRT.
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