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Functional substrate mapping characteristics during sinus rhythm predicts critical isthmus of reentrant atrial
Hikmet Yorgun1,2, Cem Çöteli1, Gül Sinem Kılıç1
1Department of Cardiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
Insights
Functional substrate mapping during sinus rhythm effectively identifies critical isthmuses for atrial tachycardia (AT). Deceleration zones pinpoint slow conduction in low-voltage areas, guiding ablation strategies for atrial scar patients.
Area of Science:
- Electrophysiology
- Cardiology
- Medical Imaging
Background:
- Atrial tachycardia (AT) is a common arrhythmia in patients with atrial scar.
- Predicting the critical isthmus (CI) of AT using late activation mapping during sinus rhythm requires systematic evaluation.
- This study investigates functional substrate mapping (FSM) characteristics in relation to the CI of reentrant ATs in patients with atrial low-voltage areas.
Purpose of the Study:
- To evaluate the utility of atrial late activation mapping during sinus rhythm for predicting the critical isthmus (CI) of atrial tachycardia (AT).
- To investigate the relationship between functional substrate mapping (FSM) characteristics and the CI of reentrant ATs in patients with underlying atrial low-voltage areas.
Main Methods:
- 35 patients with left AT undergoing catheter ablation with 3D high-density mapping were enrolled.
- Voltage mapping and isochronal late activation mapping were performed during sinus/paced rhythm to identify deceleration zones (DZ).
- Activation mapping during AT induction identified the CI, and AT recurrence was monitored post-ablation.
Main Results:
- Low-voltage areas (<0.5 mV) constituted 37.1% of the left atrium.
- Deceleration zones (DZ) were identified in low-voltage areas and colocalized with all critical isthmuses (CI) of reentrant ATs.
- The positive predictive value of DZs for detecting CI was 80.4%, with 74.3% freedom from AT recurrence post-procedure.
Conclusions:
- Functional substrate mapping (FSM) during sinus rhythm is useful for predicting the CI of AT.
- Deceleration zones (DZ) exhibit fragmented signals and slow conduction, guiding ablation strategies in atrial scar.
- This approach aids in tailoring ablation strategies for patients with underlying atrial scar and AT.
Background:
Atrial tachycardia (AT) is a commonly encountered rhythm disorder in patients with underlying atrial scar. The role of atrial late activation mapping during sinus rhythm to predict the critical isthmus (CI) of AT has yet to be systematically evaluated. We aimed to investigate the relationship between the functional substrate mapping (FSM) characteristics and the CI of reentrant ATs in patients with underlying atrial low-voltage areas.
Methods:
Patients with history of left AT who underwent catheter ablation with 3D mapping using high-density mapping were enrolled. Voltage map and isochronal late activation mapping were created during sinus/paced rhythm to detect deceleration zones (DZ). Electrograms with continuous-fragmented morphology were also tagged. After induction of AT, activation mapping was performed to detect CI of the tachycardia. Atrial tachyarrhythmia (ATa) recurrence was defined as detection of atrial fibrillation or AT (≥30 s) during the follow-up.
Results:
Among 35 patients [mean age: 62 ± 9, gender: 25 (71.5%) female] with left AT, a total of 42 reentrant ATs induced. Voltage mapping during sinus rhythm revealed low-voltage area of 37.1 ± 23.8% of the left atrium. The mean value of bipolar voltage, EGM duration, and conduction velocity during sinus rhythm corresponding to CI of ATs were 0.18 ± 0.12 mV, 133 ± 47 ms, and 0.12 ± 0.09 m/s, respectively. Total number of DZs per chamber was 1.5 ± 0.6, which were located in the low-voltage zone (<0.5 mV) detected by high-density mapping. All CIs of reentry were colocalized with DZs detected during FSM. The positive predictive value of DZs to detect CI of inducible ATs is 80.4%. Freedom from ATa after the index procedure was 74.3% during a mean follow-up of 12.2 ± 7.5 months.
Conclusion:
Our findings demonstrated the utility of FSM during sinus rhythm to predict the CI of AT. DZs displayed continuous-fragmented signal morphology with slow conduction which may guide to tailor ablation strategy in case of underlying atrial scar.
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