Pleomorphic ventricular tachycardia in dilated cardiomyopathy is a strong predictor of VT recurrence after ablation independent of cardiac function: Comparison with ischemic cardiomyopathy
Authors: Kimura Y , De Riva M , Ebert M , Glashan C , Piers SRD , Trines SA , Wijnmaalen AP , Zeppenfeld K 
Published: May 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background

Compared to ICM patients, subgroups of DCM patients show higher VT recurrence rates after catheter ablation (CA), despite similar percentages of acute non-inducibility. Pleomorphic VTs (PL-VT) have been reported in ICM patients with fibrotic remodeling and progressive heart failure. Diffuse fibrosis is the dominant scar pattern in DCM. In these patients PL-VT may occur independent of cardiac function.

Aim

To investigate the prevalence, relation with cardiac function, and impact of PL-VT on long-term ablation outcome in patients with ICM and DCM.

Methods

Consecutive patients with ICM or DCM undergoing VT ablation (ICM 2009-2016; DCM 2008-2018) were included. PL-VT was defined as ≥1 spontaneous change of the 12-lead VT morphology lasting for ≥6 consecutive beats during the same induced VT episode. Complete procedural success was defined as non-inducibility of any VT at the end of the procedure. Patients were followed for VT recurrence and mortality.

Results

A total of 247 patients (86% men, age 63 ± 13 years) underwent CA for monomorphic VT, 152 with ICM (62%), and 95 with DCM (38%). Complete procedural success was achieved in 39% in ICM vs. 37% in DCM, respectively. PL-VT was observed in 22 and 29 patients with ICM and DCM, respectively (14% vs. 31%, P = 0.003). Among ICM patients, PL-VT was associated with a lower LVEF (PL-VT+ 28 ± 9% vs. PL-VT- 34 ± 12%, P = 0.02) and only occurred if LVEF was &lt;40%. In contrast, in DCM patients, PL-VT was not related to cardiac function and occurred in 27% of patients with an EF &gt;40%. After propensity score matching to account for baseline differences (age, gender, LVEF, prior VT ablation, VT storm, and amiodarone use), between ICM vs. DCM patients, the PLVT incidence was 4 times higher in DCM patients (7% [4/60] vs. 28% [17/60], P = 0.003).
During a median follow-up of 30 months, 79 (32%) patients died (ICM 48 [32%), DCM 31 [33%], P = 0.88) and 120 (49%) patients had VT recurrence (ICM 59 [39%], DCM 61 [64%], P &lt; 0.001). In Kaplan-Meier analyses, inducibility of PL-VT was associated with mortality only in ICM but not in DCM patients. In contrast, PL-VT was associated with poorer VT-free survival in both ICM and DCM patients (figure). In multivariate analyses, PL-VT remained a significant predictor of VT recurrence in DCM (HR 3.00, 95% CI 1.75-5.11, P &lt; 0.001), independent of LVEF, (likely) pathogenic genetic mutation, amiodarone, endocardial low bipolar/unipolar voltage areas, dominant anteroseptal substrate, and non-complete acute procedural success, but not in ICM.

Conclusions

PL-VT was associated with poor systolic function and mortality in ICM, whereas it was independent of LVEF and the most decisive parameter for VT recurrence in DCM. This data suggests that PL-VT in DCM is a marker of a complex arrhythmic substrate challenging to control by CA. Abstract Figure. Kaplan-Meier analyses