What is the clinical evidence from this study?

Study design: Cohort. Population: Nonischemic cardiomyopathy with septal ventricular tachycardia (n=95). Intervention: Catheter ablation resulting in collateral injury of the conduction system (CICS) vs. Catheter ablation without CICS. Primary outcome: VT recurrence (p=.94).

What does this research mean for the field?

Collateral injury of the conduction system during septal ventricular tachycardia ablation in patients with nonischemic cardiomyopathy worsens left ventricular ejection fraction without significantly improving ventricular tachycardia control compared to sparing the conduction system. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

April 16, 2020

Collateral injury of the conduction system during catheter ablation of septal substrate in nonischemic cardiomyopathy

Key Result

Collateral injury of the conduction system during septal VT ablation in NICM patients led to similar VT recurrence (14% vs 12%, P=.94) but worsened LVEF (-5% vs 0%, P<.01) compared to no injury.

Study Design

Type

Cohort (n=95)

Structured PICO

Does collateral injury of the conduction system during catheter ablation of septal VT worsen clinical and echocardiographic outcomes in patients with nonischemic cardiomyopathy?

Population

95 consecutive patients with nonischemic cardiomyopathy (NICM) undergoing catheter ablation of septal ventricular tachycardia (VT)

Intervention

Catheter ablation of septal VT resulting in collateral injury of the conduction system (CICS) in patients with no baseline conduction abnormalities (n=28)

Comparator

Catheter ablation of septal VT without resulting in CICS (n=17), or in patients with preexisting conduction abnormalities or biventricular pacing (n=50)

Outcome

VT recurrence, death/transplant, worsening of left ventricular ejection fraction (LVEF), and need for new biventricular pacing at median 15 months follow-uphard clinical

Avoiding collateral injury to the conduction system during septal VT ablation in nonischemic cardiomyopathy preserves systolic function and reduces the need for biventricular pacing while maintaining acceptable VT control.

Main Result

Absolute Event Rate: 14% vs 12%

p-value: p=.94

Abstract

INTRODUCTION: In patients with nonischemic cardiomyopathy (NICM) little is known about the clinical impact of catheter ablation (CA) of septal ventricular tachycardia (VT) resulting in the collateral injury of the conduction system (CICS). METHODS AND RESULTS: Ninety-five consecutive patients with NICM underwent CA of septal VT. Outcomes in patients with no baseline conduction abnormalities who developed CICS (group 1, n = 28 29%) were compared to patients with no CICS (group 2, n = 17 18%) and to patients with preexisting conduction abnormalities or biventricular pacing (group 3, n = 50 53%). Group-1 patients were younger, had a higher left ventricular ejection fraction and a lower prevalence of New York Heart Association III/IV class compared to group 3 while no significant differences were observed with group 2. After a median follow-up of 15 months, VT recurred in 14% of patients in group 1, 12% in group 2 (P = .94) and 32% in group 3 (P = .08) while death/transplant occurred in 14% of patients in group 1, 18% in group 2 (P = .69) and 28% in group 3 (P = .15). A worsening of left ventricular ejection fraction (LVEF) (median LVEF variation, -5%) was observed in group 1 compared to group 2 (median LVEF variation, 0%; P < .01) but not group-3 patients (median LVEF variation, -4%; P = .08) with a consequent higher need for new biventricular pacing in group 1 (43%) compared to group 2 (12%; P = .03) and group 3 (16%; P < .01). CONCLUSIONS: In patients with NICM and septal substrate, sparing the abnormal substrate harboring the conduction system provides acceptable VT control while preventing a worsening of the systolic function.

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