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The transmural activation interval: a new mapping tool to identify ventricular tachycardia substrates in right
Jeroen Venlet1, Sebastiaan R Piers1, Jarieke Hoogendoorn1
1Willem Einthoven Center for Cardiac Arrhythmia Research and Management, Department of Cardiology, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands.
Insights
Transmural activation delay during sinus rhythm can identify ventricular tachycardia (VT) substrates in right ventricular cardiomyopathy (RVCM). This finding offers a new mapping tool for substrate-based ablation of VT in RVCM patients.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Imaging
Background:
- Right ventricular cardiomyopathy (RVCM) can lead to intramural scarring, potentially creating substrates for subepicardial ventricular tachycardia (VT) circuits.
- Identifying these VT substrates is crucial for effective ablation strategies in RVCM patients.
Purpose of the Study:
- To investigate if transmural activation delay during sinus rhythm (SR) can identify VT substrates in patients with RVCM.
- To evaluate the accuracy of transmural activation interval (TAI) and maximal activation interval (MAI) in predicting VT-related epicardial sites.
Main Methods:
- Consecutive RVCM patients undergoing VT mapping and ablation were enrolled.
- Endocardial-epicardial point pairs were analyzed to determine TAI and MAI.
- VT-related sites were identified through substrate and activation mapping.
Main Results:
- TAI and MAI were significantly longer at VT-related sites compared to other scar sites (P < 0.001).
- TAI and MAI accurately identified epicardial VT-related sites with optimal cut-offs (TAI 17 ms, MAI 45 ms, AUC 0.81).
- TAI and MAI demonstrated superior predictive accuracy for VT-related sites compared to voltage and electrogram duration.
Conclusions:
- Transmural activation delay in SR is a valuable tool for identifying VT substrates in RVCM.
- TAI and MAI can serve as important new mapping parameters for substrate-based VT ablation in RVCM.
Aims:
In right ventricular cardiomyopathy (RVCM), intramural scar may prevent rapid transmural activation, which may facilitate subepicardial ventricular tachycardia (VT) circuits. A critical transmural activation delay determined during sinus rhythm (SR) may identify VT substrates in RVCM.
Methods And Results:
Consecutive patients with RVCM who underwent detailed endocardial-epicardial mapping and ablation for scar-related VT were enrolled. The transmural activation interval (TAI, first endocardial to first epicardial activation) and maximal activation interval (MAI, first endocardial to last epicardial activation) were determined in endocardial-epicardial point pairs located <10 mm apart. VT-related sites were determined by conventional substrate mapping and limited activation mapping when possible. Nineteen patients (46 ± 16 years, 84% male, 63% arrhythmogenic right ventricular cardiomyopathy, 37% exercise-induced arrhythmogenic remodelling) were inducible for 44 VT [CL 283 (interquartile range, IQR 240-325)ms]. A total of 2569 endocardial-epicardial coupled point pairs were analysed, including 98 (4%) epicardial VT-related sites.The TAI and MAI were significantly longer at VT-related sites compared with other electroanatomical scar sites [TAI median 31 (IQR 11-50) vs. 2 (-7-11)ms, P < 0.001; MAI median 65 (IQR 45-87) vs. 23 (13-39)ms, P < 0.001]. TAI and MAI allowed highly accurate identification of epicardial VT-related sites (optimal cut-off TAI 17 ms and MAI 45 ms, both AUC 0.81). Both TAI and MAI had a better predictive accuracy for VT-related sites than endocardial and epicardial voltage and electrogram (EGM) duration (AUC 0.51-0.73).
Conclusion:
The transmural activation delay in SR can be used to identify VT substrates in patients with RVCM and predominantly hemodynamically non-tolerated VT, and may be an important new mapping tool for substrate-based ablation.
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