Overlap in scarring phenotypes between non-dilated left ventricular cardiomyopathy and arrhythmogenic left ventricular cardiomyopathy: Implications for prognostic stratification

Le résumé fourni par la source

Abstract Background The latest ESC guidelines on cardiomyopathies have introduced the concept of Non-Dilated Left Ventricular Cardiomyopathy (NDLVC) in contrast to that of Left Dominant Arrhythmogenic Cardiomyopathy (ALVC), with which it partially overlaps. However, aside from cases with a known genetic etiology—particularly those associated with high-risk genes—there is limited data comparing the prognosis of NDLVC and ALVC. Purpose To assess the influence of phenotypic expression on clinical outcomes in NDLVC patients without identified genetic mutations compared to ALVC patients. Methods We compared the clinical and instrumental features of 42 NDLVC gene-elusive patients, without a prior history of myocarditis, to those of 65 ALVC patients carrying known desmosomal mutations and evaluated their respective clinical outcomes. Major adverse cardiovascular events (MACE) were defined as a composite of life-threatening ventricular arrhythmias (LVTA), sudden cardiac death, cardiovascular death, heart failure, and hot phases episodes. Results The NDLVC group showed a significantly higher male predominance (p=0.02), a greater likelihood of proband status (p<0.001) and more frequent initial presentation with LTVA compared to ALVC patients, who were more often identified for familial screening (p=0.02). Regarding electrocardiographic parameters (ECG), the ALVC cohort showed a significantly higher prevalence of low voltages in peripheral leads (p=0.04). Both groups displayed a high degree of fibrosis on Cardiac Magnetic Resonance (CMR), particularly with a ring-like distribution (86% ALVC vs. 88% NDLVC, p=1). At CMR no significant differences were observed in mean left ventricular (LV) ejection fraction (EF) between the two groups (57±7.8% in NDLVC vs 52±8.7% in ALVC, p>1), while LV dilatation was significantly higher in the ALVC cohort (mean end-diastolic volume 95±22 ml/mq in ALVC vs 84±9.6 ml/mq in NDLVC, p<0.001). During a median follow-up of 36 months (IQR 83.5), no differences in MACE were observed between the two groups (p=0.99). Additionally, no significant differences were found in the individual outcomes included in the MACE definition. Conclusion Our study demonstrates that gene-elusive NDLVC patients and ALVC patients exhibit a largely overlapping phenotype, primarily due to the high degree of fibrosis on CMR, often with a ring-like distribution, more than to LVEF or LV dilatation. The increased proportion of proband status and first presentation with LTVA observed in the NDLVC group is likely attributed to the limited awareness for this newly defined entity. Furthermore, in patients with epicardial fibrosis, the presence of low voltages in peripheral leads on ECG is more indicative of ALVC linked to a desmosomal mutation than of a gene-elusive NDLVC form, despite a comparable degree of fibrosis. Finally, in patients with epicardial fibrosis, arrhythmic outcomes are more closely linked to the extent of scarring than to the underlying genetic cause.Genetic Distribution in ALVC cohort ECG and CMR Findings in ALVC e NDLC

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.