Ventricular mapping during atrial and right ventricular pacing: relation of electrogram parameters to ventricular
Corinna B Brunckhorst1, Etienne Delacretaz, Kyoko Soejima
1University Hospital, Zürich, Switzerland.
Insights
Identifying critical circuits for ventricular tachycardia (VT) after myocardial infarction is key for ablation. This study developed a model using electrograms and pace mapping to predict reentry locations, improving ablation success without needing VT induction.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Ventricular tachycardia (VT) post-myocardial infarction often results from reentry circuits in the infarct border zone.
- Identifying these circuits non-invasively is crucial for effective VT ablation.
- Current methods may require inducing VT, posing risks to patients.
Purpose of the Study:
- To develop a predictive model for VT reentry circuit locations.
- To utilize characteristics of sinus or paced electrograms and pace mapping (PM) for prediction.
- To guide catheter ablation of VT without requiring VT induction.
Main Methods:
- Left ventricular electroanatomic mapping using the CARTO system in 16 patients.
- Analysis of local activation time (LAT), onset (ONS), end (END), duration (DUR), and amplitude (AMP) during atrial pacing (AP) and right ventricular pacing (RVP).
- Comparison of electrogram parameters and stimulus-to-QRS intervals (S-QRS) with ablation target areas.
Main Results:
- Multivariate analysis identified LAT, END, DUR, AMP (AP), END, AMP (RVP), and S-QRS as independent predictors of target sites.
- A combination of DUR (AP), AMP (RVP), and S-QRS achieved 80% sensitivity and 64% specificity for target identification.
- Significant differences (p < 0.05) in parameters were observed between target and non-target sites.
Conclusions:
- Ablation guided by combined abnormal electrograms from different rhythms can effectively treat VT.
- This approach may reduce the need for VT induction during ablation procedures.
- Fixed regions of electrical block are likely important for reentry and identifiable during sinus rhythm.
Introduction:
Ventricular tachycardia (VT) late after myocardial infarction is usually due to reentry in the border zone of the infarct area. Identification of critical parts of the VT reentry circuit by catheter mapping without needing to induce VT is a desirable goal for VT ablation. The aim of this study was to develop a model to predict reentry circuit locations based on characteristics of sinus or paced electrograms and pace mapping (PM) recorded from the infarct region.
Methods:
Left ventricular electroanatomic mapping with the CARTO mapping system was performed in 16 male patients with recurrent VT late after myocardial infarction. A total of 1072 left ventricular sites were recorded during atrial pacing (AP) and right ventricular pacing (RVP), and the corresponding electrograms were analyzed for their local activation time (LAT), onset (ONS), end (END), duration (DUR), and amplitude (AMP) in each pacing sequence. At 1041 of these sites, PM was performed; the resulting stimulus to QRS intervals (S-QRS) was determined at 931 sites, the remaining 110 sites did not capture. All the obtained parameters were compared with the location of 18 ablation target areas with a radius of 2 cm defined by success of radiofrequency (RF) ablation or entrainment during VT, or both.
Results:
Of 1072 sites, 227 (21%) were in the target and 845 (79%) were outside the target. All parameters were significantly different (p < 0.05) in AP and in RVP between inside and outside the target in a univariate analysis. In a multivariate analysis LAT, END, DUR, and AMP in AP, END and AMP in RVP, and S-QRS were independent predictors for the target (p < 0.05). A combination of selected parameters of these predictors (DUR in AP, AMP in RVP, and S-QRS) had a specificity of 64% with a sensitivity of 80% for the target.
Conclusion:
The observations suggest that ablation guided by a combination of abnormal electrograms in different rhythms can be useful to ablate VT and reduce the necessity of VT induction. Anatomically fixed regions of block may be important for reentry and be identifiable during sinus rhythm.
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