Looking for appropriate criterias for SCD prevention: prognostic role of MRI in patients with nonischemic ventricular arrhythmias
Authors: Berdibekov B , Aleksandrova S , Bulaeva N , Gromova O , Golukhova E 
Published: October 2021

Abstract

Background
Currently left ventricular ejection fraction (LVEF) remains the only indicator for identifying candidates for implantable cardioverter-defibrillator (ICD)therapy for the primary prevention of sudden cardiac death (SCD). However the majority of patients suffering SCD have a preserved LVEF and some of them with poor LVEF do not benefit from ICD therapy. Late gadolinium enhancement (LGE) on cardiac-MRI (CMR) has been proposed as an independent predictor of ventricular arrhythmias. Limited data exist on the role and methods of LGE quantification in patients with a nonischemic ventricular arrhythmias.

Purpose
The goal of this study is to explore whether theextent of LGE would improve risk stratification in patients with a nonischemic ventricular arrhythmias with an indication for implantable cardioverter-defibrillator (ICD) therapy for the primary or secondary prevention of SCD.

Methods
Fifty six patients with a nonischemic ventricular arrhythmias underwent LGE-CMR prior to ICD implantation for primary and secondary prevention of SCD. LGE extent was quantified using both the full-width half-maximum (FWHM) andthe standard deviation–based (2-SD) method. The primary endpoint was appropriate ICD discharge for sustained ventricular tachyarrhythmia.

Results
During a median follow-up of 18 [11,5–26,0] months the primary endpoint occurred in 22 patients. The median percentage of LV myocardium fibrosis assessed by the 2-SD method was 9,8 [6,0–18,8]%, while for the FWHM method it was 5,1 [3,0–10,6]% (p&lt;0,001). Intra-observer and inter-observer variability of the FWHM technique was excellent, intraclass correlation coefficients (ICC) 0,97 (95% CI: 0,92–0,99) for intraobserver variability and 0,95 (95% CI: 0,85–0,98) for interobserver variability. The ICC for the 2-SD method were lower: 0,92 (95% CI: 0,76–0,97) and 0,90 (95% CI: 0,69–0,96), for intra- and interobserver variability, respectively. By Cox univariate regression analysis, past syncope, HR: 3,14; (CI: 1,28–7,73), past sustained VT, HR: 8,24; (CI: 2,43–27,96), the presence of LBBB before implantation cardiac resynchronization therapy defibrillator (CRT-D), HR: 0,22; (CI: 0,05–0,96) as well as extent of LGE, HR: 1,067; per 1% increase in the extent of LGE, (CI: 1,029–1,107) demonstrated the strongest association with the appropriate ICD discharge. In multivariate regression analysis, the history of sustained VT, HR: 9,17; (CI: 2,60–32,38; p=0,001) and the value of the extent of LGE, HR: 1,081; per 1% increase in volume of LGE, (CI: 1,034–1,131; p=0,001) demonstrated an independent association with the appropriate ICD discharge.

Conclusions
FWHM is the optimal semi-automated quantification method in patients with nonischemic ventricular arrhythmias, demonstrating the highest technical consistency. LGE extent is an independent predictor of adverse outcomes in patients with nonischemic ventricular arrhythmia and may have an important role in risk stratification.

Funding Acknowledgement
Type of funding sources: None. LGE QuantificationEvent-Free Survival