Ring-Like Scar Architecture and Arrhythmic Outcomes of Patients With Nondilated Left Ventricular Cardiomyopathy Treated With Ventricular Tachycardia Ablation.

Background

Nondilated left ventricular cardiomyopathy (NDLVC) is characterized by an elevated arrhythmic burden and frequent presence of ring-like late gadolinium enhancement (RL-LGE) pattern. However, the arrhythmic substrate and outcomes after ventricular tachycardia (VT) ablations remain undefined.

Objectives

This study sought to characterize the arrhythmogenic substrate using postprocessed cardiac magnetic resonance and assess VT recurrence after ablation in patients with NDLVC.

Methods

Consecutive patients with NDLVC undergoing VT ablation at the Hospital Clínic of Barcelona were included.

Results

Thirty-seven patients were included (age 44 years [IQR: 39-55]; 78% male; left ventricular ejection fraction 45% [IQR: 40-52]). RL-LGE was observed in 21 of 37 (57%) patients. Compared with patients without it, patients with RL-LGE had lower left ventricular ejection fraction (40% [38% to 45%] vs 51% [49% to 55%], P < 0.0001), greater scar burden (16.2% [12.7% to 20.0%] vs 5.4% [5.0% to 6.0%], P < 0.0001), larger number of arrhythmogenic conducting channels (3 [2-4] vs 1 [1-2], P < 0.0001), and longer conducting channels (34 mm [29-38 mm] vs 12 mm [10-14 mm], P < 0.0001). Over a median of 3 years of follow-up, 30% of patients had VT recurrence with event rate of 10.2%/year. Dense scar (HR: 1.13, per 1% increment; 95% CI: 1.05-1.22; P = 0.002) and borderzone scar burden (HR: 1.27; 95% CI: 1.11-1.45; P = 0.001), number (HR: 2.35; 95% CI: 1.42-3.91; P = 0.001) and the length of conducting channels (HR: 1.04 per 1 mm increase; 95% CI: 1.01-1.06; P = 0.006) were associated with VT recurrence. The adjusted risk of VT recurrence was 24-fold higher in patients with RL-LGE (HR: 24.0; 95% CI: 2.8-207.1; P = 0.004).

Conclusions

RL-LGE identifies patients with NDLVC with a more complex arrhythmogenic substrate and a poorer outcome after VT ablation.