Unmasking the ring: substrate features and outcomes after ventricular tachycardia ablation in patients with ring-like late gadolinium enhancement pattern
R Pittorru, N Pierucci, T Rosseel, M Regany-Closa, J B Guichard, E Ayauja, P Bhagirath, F Migliore, J M Tolosana, E Guasch, E Arbelo, J Brugada, L Mont, A Porta Sanchez, I Roca-LuqueAbstract
Background
Catheter ablation of ventricular tachycardia (VT) in nonischemic cardiomyopathy (NICM) shows less favorable outcomes and higher recurrence than in ischemic cardiomyopathy, mainly due to the complex arrhythmogenic substrate. Among NICM causes, arrhythmogenic cardiomyopathy (ACM) with left ventricular (LV) involvement has gained attention, particularly through cardiac magnetic resonance (CMR). A typical feature is the ring-like late gadolinium enhancement (RL-LGE), reflecting diffuse subepicardial or midmyocardial fibrosis encircling the LV wall. Data on substrate characteristics and post-ablation outcomes in patients with RL-LGE remain limited.
Objective
To describe the arrhythmogenic substrate and post-ablation VT recurrence-free survival in ACM patients with RL-LGE versus those without.
Methods
We retrospectively included consecutive patients with biventricular or left-dominant ACM (BIV-ACM or LD-ACM) undergoing VT ablation at our Hospital Clínic (2016–2025). Other etiologies were excluded. RL-LGE was defined as subepicardial or midmyocardial enhancement involving ≥3 contiguous LV segments on one short-axis slice. All patients underwent CMR and/or computed tomography with 3D reconstruction (ADAS3D software). VT recurrences were assessed during follow-up, and event-free survival was estimated using Kaplan–Meier curves.
Results
Thirty-two patients were included (mean age 46 ± 14 years; 75% male; LV ejection fraction 40 ± 11%), 20 with BIV-ACM and 12 with LD-ACM. RL-LGE was identified in 18 (56%), and septal involvement in 20. Genetic testing (performed in 91%) revealed LMNA (n=6), TTN (n=5), and DSP (n=5) as the most frequent variants. Patients with RL-LGE showed more conducting channels (2.7±1.4 vs 1.6±0.6; OR 4.47, 95% CI 1.2–15.7, p=0.019), longer channel length (28±8 vs 14±11 mm; OR 1.2, 95% CI 1.08–1.3, p=0.046), more channels >10 mm (2.4±1.2 vs 1.1±0.9; OR 3.2, 95% CI 1.2–8.2, p=0.015), and larger border zone core mass (28.2±13.4 vs 21.3±12 g; OR 1.3, 95% CI 1.07–1.21, p=0.022). A combined endo-epicardial or purely epicardial approach was used in 17 patients, with no difference in recurrence-free survival (log-rank p=0.40). Over a median follow-up of 36 months (IQR 8–70), VT-free survival was lower in patients with RL-LGE (8/18 vs 2/16, log-rank p=0.048). No difference was seen with septal LGE (log-rank p=0.464).
Conclusions
Patients with RL-LGE show a more complex arrhythmogenic substrate, with more and longer conducting channels and greater border zone core mass. Regardless of ablation strategy, RL-LGE was associated with higher VT recurrence during follow-up, identifying it as a marker of disease severity and advanced arrhythmogenic substrate less responsive to ablation.