Larger spatial ventricular gradient magnitude is associated with higher rates of response to cardiac
Alyssa J Shepherd1, Hans F Stabenau1, Arunashis Sau2
1Harvard-Thorndike Electrophysiology Institute, Departmet of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Insights
Spatial ventricular gradient magnitude (SVGmag) predicts cardiac resynchronization therapy (CRT) response in heart failure patients. Higher SVGmag indicates a greater likelihood of CRT success, outperforming traditional QRS duration metrics.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) is vital for systolic heart failure (HF), yet patient response varies significantly.
- Identifying optimal candidates for CRT is crucial for improving treatment efficacy.
- Spatial ventricular gradient (SVG) measures myocardial electromechanical heterogeneity and is linked to HF development.
Purpose of the Study:
- To investigate the association between spatial ventricular gradient (SVG) and patient response to cardiac resynchronization therapy (CRT).
- To determine if SVG can serve as a predictive biomarker for CRT success.
Main Methods:
- Retrospective analysis of 162 patients undergoing CRT implantation (2015-2022).
- Electrocardiograms (ECGs) were converted to vectorcardiograms (VCGs) to calculate SVG components and magnitude (SVGmag).
- CRT response was defined as a ≥10% increase in left ventricular ejection fraction (LVEF) post-therapy; logistic regression was used for analysis.
Main Results:
- A significant association was found between higher pre-CRT SVGmag and increased odds of CRT response (ORadj 1.78 per SD increase, P=.009).
- Patients in the highest tertile of pre-CRT SVGmag showed a 4.5-fold increased odds of CRT response (P=.003).
- SVGmag demonstrated superior predictive performance for CRT response compared to QRS duration.
Conclusions:
- Spatial ventricular gradient magnitude (SVGmag) is an independent predictor of CRT response in heart failure patients.
- SVGmag holds promise as a novel biomarker for patient selection for CRT.
- Further prospective studies are warranted to validate these findings.
Background:
Cardiac resynchronization therapy (CRT) improves systolic heart failure (HF) outcomes, but many patients do not benefit. Improved methods for identifying patients likely to benefit from CRT are needed. The spatial ventricular gradient (SVG) is a vectorcardiographic measure of myocardial electromechanical heterogeneity that is associated with incident HF. The relationship between SVG and CRT response is unknown.
Objective:
This study aimed to investigate associations between SVG and CRT response.
Methods:
Retrospective analysis of patients presenting for clinically-indicated CRT implant in 2015-2022. Pre-CRT electrocardiograms (ECGs) were transformed into vectorcardiograms (VCGs), and SVG vector X, Y, and Z components were calculated as areas under the X, Y and Z VCG QRST complexes, respectively. SVG magnitude (SVGmag) was calculated as SVG vector length. CRT response, defined as left ventricular ejection fraction (LVEF) increase ≥10% post-CRT, was assessed using multivariable logistic regression.
Results:
Among 162 patients (median age 68 years, 62% male, 76% non-ischemic HF, median LVEF 26%, median QRS duration 162ms, 89% left bundle branch block), 69% had CRT response. After adjustment, larger pre-CRT SVGmag was associated with higher odds of CRT response: adjusted odds ratio (ORadj) 1.78 per 1 standard deviation increase, P = .009. Predicted probabilities of CRT response ranged between ∼50% for the lowest SVGmag values, to ∼90% for the highest SVGmag values, and patients in the highest pre-CRT SVGmag tertile had and ORadj 4.5, P = .003 for CRT response. Larger post-CRT decreases in SVGmag were also associated with increased CRT response. SVGmag performed better than QRS area for predicting CRT response.
Conclusion:
SVGmag is independently associated with CRT response and warrants prospective study.
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