Significance of coherent mapping in unveiling slow conduction zones of ventricular tachycardia substrate in ischemic cardiomyopathy.

Background: Identifying slow conduction zones (SCZs) within the ventricular tachycardia (VT) substrate remains a major challenge in ischemic cardiomyopathy (ICM). We aimed to evaluate the role of coherent mapping (CM) in identifying SCZs within low-voltage areas (LVAs) in VT substrate mapping and assess its impact on VT ablation outcomes.

Methods: This retrospective study included 32 patients with ICM who underwent ablation for recurrent VT. CM-SCZs were compared with traditional substrate markers, including late potentials (LPs), local abnormal ventricular activities (LAVAs), and ILAM-based deceleration zones (DZs). Ablation strategies targeting CM-SCZs were analyzed in relation to procedural and clinical outcomes, including VT recurrence and total radiofrequency (RF) ablation time.

Results: CM-SCZs were consistently identified adjacent to LVAs in all cases, with a mean area of 5.2 ± 2.3 cm². CM-SCZs colocalized with ILAM-based DZs in 56.3% of cases and overlapped with LPs and LAVAs in selected patients. Among patients who remained free from VT recurrence, total RF ablation time was significantly longer (938 ± 354 vs. 380 ± 448 s, p = 0.03), suggesting that more extensive substrate modification played a role in arrhythmia suppression. Furthermore, patients with VT recurrence had lower post-ablation non-inducibility rates (50% vs. 91.6%, p = 0.02).

Conclusion: CM improves the identification of SCZ within the VT substrate and enhances substrate-based ablation strategies. Incorporating CM-SCZs into VT ablation protocols may improve procedural success and reduce arrhythmia recurrence. Future studies should validate these findings and explore role of CM in broader patient populations.