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Twelve-Lead ECG Optimization of Cardiac Resynchronization Therapy in Patients With and Without Delayed Enhancement on
Ryan M Gage1, Akbar H Khan1, Imran S Syed1
11 United Heart & Vascular Clinic St. Paul MN.
Insights
Delayed enhancement (DE) on MRI indicates worse outcomes for cardiac resynchronization therapy (CRT). Device optimization improves CRT effectiveness, especially in patients with DE, reducing electrical dyssynchrony and enhancing ejection fraction.
Area of Science:
- Cardiology
- Medical Imaging
- Electrophysiology
Background:
- Delayed enhancement (DE) on MRI correlates with adverse outcomes in heart failure patients.
- DE is linked to ventricular arrhythmias, poorer left ventricular mechanics, and adverse events.
- The impact of DE on cardiac resynchronization therapy (CRT) outcomes requires further investigation.
Purpose of the Study:
- To investigate how DE impacts CRT outcomes.
- To evaluate the effect of CRT optimization on patients with and without DE.
- To assess the relationship between electrical dyssynchrony and CRT response in the presence of DE.
Main Methods:
- Retrospective analysis of 130 patients with ejection fraction (EF) ≤40% and QRS duration ≥120 ms.
- Contrast cardiac MRI for DE assessment and pre- and 1-year post-CRT echocardiograms for EF changes.
- Patient groups: no DE, midwall septal stripe, and scar; CRT optimization status (routine vs. 12-lead ECG guided).
Main Results:
- Patients without DE showed significantly better improvement in EF (∆ EF) post-CRT compared to those with DE (13±10 vs. 4±10 units; P<0.01).
- CRT optimization led to greater ∆ EF in patients with midwall stripe (12±12 units; P=0.01) and scar (5±10 units; P=0.04) but not in the no-DE group.
- Device optimization reduced electrical dyssynchrony (standard deviation of activation times) specifically in patients with DE (P<0.01).
Conclusions:
- DE on cardiac MRI is a significant predictor of suboptimal EF outcomes after CRT.
- CRT device optimization improves EF and reduces electrical dyssynchrony, particularly benefiting patients with DE.
- MRI-derived DE patterns can help personalize CRT strategies for better patient outcomes.
Abstract:
Background Delayed enhancement ( DE ) on magnetic resonance imaging is associated with ventricular arrhythmias, adverse events, and worse left ventricular mechanics. We investigated the impact of DE on cardiac resynchronization therapy ( CRT ) outcomes and the effect of CRT optimization. Methods and Results We studied 130 patients with ejection fraction ( EF ) ≤40% and QRS ≥120 ms, contrast cardiac magnetic resonance imaging, and both pre- and 1-year post- CRT echocardiograms. Sixty-three (48%) patients did not have routine optimization of CRT . The remaining patients were optimized for wavefront fusion by 12-lead ECG . The primary end point in this study was change in EF following CRT . To investigate the association between electrical dyssynchrony and EF outcomes, the standard deviation of activation times from body-surface mapping was calculated during native conduction and selected device settings in 52 of the optimized patients. Patients had no DE (n=45), midwall septal stripe (n=30), or scar (n=55). Patients without DE had better ∆ EF (13±10 versus 4±10 units; P<0.01). Optimized patients had greater ∆ EF in midwall stripe (2±9 versus 12±12 units; P=0.01) and scar (0±7 versus 5±10; P=0.04) groups, but not in the no- DE group. Patients without DE had greater native standard deviation of activation times ( P=0.03) and greater ∆standard deviation of activation times with standard programming ( P=0.01). Device optimization reduced standard deviation of activation times only in patients with DE ( P<0.01). Conclusions DE on magnetic resonance imaging is associated with worse EF outcomes following CRT . Device optimization is associated with improved EF and reduced electrical dyssynchrony in patients with DE .
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