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Gated single photon emission computed tomography imaging of left ventricular mechanical dyssynchrony: Predictive
Agnieszka Stępień-Wroniecka1, Wojciech Szot2, Ewa Dziewięcka3
1Doctoral School of Medical and Health Sciences, Jagiellonian University Medical College, Kraków, Poland; Department of Cardiac and Vascular Diseases, The Specialist Hospital of St. John Paul II in Cracow, Jagiellonian University Medical College, Prądnicka Street 80, 31-202 Krakow, Poland.
Insights
Gated-single-photon-emission computed tomography (G-SPECT) can identify left ventricular mechanical dyssynchrony (LVMD) in heart failure patients. G-SPECT parameters predict positive responses to cardiac resynchronization therapy (CRT), improving ejection fraction.
Area of Science:
- Cardiology
- Medical Imaging
Background:
- Cardiac resynchronization therapy (CRT) is recommended for heart failure with reduced ejection fraction (HFrEF) patients with electrocardiographic (ECG) criteria for electrical dyssynchrony.
- Gated-single-photon-emission computed tomography (G-SPECT) assesses left ventricular mechanical dyssynchrony (LVMD), but its predictive value for CRT response is unclear.
Purpose of the Study:
- To evaluate G-SPECT's utility in identifying LVMD.
- To assess G-SPECT's ability to predict CRT response in HFrEF patients.
Main Methods:
- Prospective enrollment of HFrEF patients (<35% LVEF) into CRT-eligible (n=60) and ineligible (n=40) groups.
- Baseline and 6-month follow-up assessments included ECG, echocardiography, and G-SPECT.
- LVMD assessed via G-SPECT parameters (HBW, PSD, entropy) at rest and stress; CRT response by LVEF change.
Main Results:
- CRT-eligible patients showed greater baseline LVMD by echocardiography and G-SPECT.
- G-SPECT parameters correlated with QRS duration and echocardiographic findings.
- Post-CRT, LVMD improved in the CRT-eligible group, with significant LVEF increases.
- Rest PSD and entropy measures predicted normalization of LVEF (super-response) in 11.9% of patients.
Conclusions:
- G-SPECT-derived LVMD parameters correlate significantly with electrical dyssynchrony (QRS duration).
- CRT implantation leads to parallel improvements in LVMD and LVEF.
Background:
Cardiac resynchronization therapy (CRT) is recommended for patients with heart failure with reduced ejection fraction (HFrEF) who meet specific electrocardiographic (ECG) criteria of electrical dyssynchrony. Gated single-photon emission computed tomography (G-SPECT) is an imaging method that allows for the assessment of left ventricular mechanical dyssynchrony (LVMD); however, its predictive value for CRT response remains uncertain. This study aimed to evaluate the utility of G-SPECT in identifying LVMD and predicting CRT response in patients with HFrEF.
Methods:
Patients with HFrEF and a LVEF <35% were prospectively enrolled and stratified into two groups: 60 patients CRT-eligible (Group 1) and 40 CRT-ineligible (Group 2). All patients underwent ECG, echocardiography, and G-SPECT imaging at baseline and at 6-month follow-up. LVMD was assessed using G-SPECT-derived parameters: (a) histogram bandwidth (HBW), (b) phase standard deviation (PSD), and (c) phase entropy, both at rest and under stress. CRT response was evaluated based on changes in LVEF.
Results:
At baseline, patients in Group 1 exhibited greater LVMD as assessed by both echocardiography and G-SPECT. All G-SPECT-derived parameters, along with septal-to-posterior wall motion delay on echocardiography, were correlated with QRS duration. After CRT, LVMD significantly improved in Group 1. Super-response, defined as EF normalization, was observed in 11.9% of patients. G-SPECT-derived LVMD parameters, particularly rest PSD and entropy measures, were significant predictors of the favorable outcome of LVEF normalization.
Conclusions:
LVMD parameters obtained from G-SPECT were significantly correlated with electrical dyssynchrony as measured by QRS duration. Following CRT implantation, LVMD improved in parallel with increases in LVEF.
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