Late gadolinium enhancement (LGE), in particular its septal location, may help identify patients with dilated and nondilated left ventricular cardiomyopathies at elevated risk of arrhythmic events, an analysis of patient data suggests. Data from the multi-center cohort analysis, published online Monday and in the May 14 issue of the Journal of the American College of Cardiology, noted that the 2023 European Society of Cardiology (ESC) guidelines for the management of cardiomyopathies differentiated dilated cardiomyopathy (DCM) from a newly introduced phenotype of non-dilated left ventricular cardiomyopathy (NDLVC). Led by Matteo Castrichini, MD, from the University of Trieste, Italy; Mayo Clinic, Rochester, Minnesota; and the University of Colorado Cardiovascular Institute, Aurora, Antonio De Luca, MD, PhD, of the University of Trieste, the team noted that the new NDLVC phenotype embraces different conditions characterized by LV hypokinesia without dilatation and LV scarring or fatty replacement regardless of LV function, “thus also including what was previously referred to as arrhythmogenic cardiomyopathy (ACM) with LV involvement.” However, they noted that the role of cardiac magnetic resonance (CMR) and genetic testing for arrhythmic risk stratification in patients with DCM and NDLVC has not been explored. Study details Castrichini, De Luca and colleagues retrospectively analyzed data from 462 patients with DCM (n=227) or NDLVC (n=235) with CMR data from four referral centers in an effort to provide a thorough characterization and assess clinical outcomes of patients over a median follow-up of 81 months. Average patient age at enrollment was 43 years, and 58% were male, said the authors, noting that the primary endpoint was a composite of sudden cardiac death (SCD) or major ventricular arrhythmias, including successfully resuscitated ventricular fibrillation (VF) or ventricular tachycardia (VT); sustained (>30 seconds) VT causing hemodynamic instability; or appropriate implantable cardioverter-defibrillator (ICD) interventions. Compared to DCM, patients with NDLVC more frequently had a family history of SCD (34% vs 25%; P = 0.02), a higher prevalence of P/LP variants in arrhythmogenic genes (40% vs 23%; P < 0.001), higher left ventricular ejection fraction (LVEF; 51% vs 36%; P < 0.001), and a higher prevalence of free-wall LGE (27% vs 14%; P < 0.001), said the authors. Conversely, DCM showed higher prevalence of pathogenic or likely pathogenic variants of nonarrhythmogenic genes (23% vs 12%; P = 0.002) and septal LGE (45% vs 32%; P = 0.004), in addition to a higher frequency of New York Heart Association (NYHA) functional class III or greater at presentation (17% vs 7%; P < 0.001) and non-sustained ventricular tachycardia (NSVT) (46% vs 34%; P = 0.012). Over the median follow-up of 81 months, the primary study outcome occurred in 98 (21%) patients, the team reported, adding that LGE with septal location (hazard ratio [HR]: 1.929; 95% confidence interval [CI]: 1.033-3.601; P = 0.039) was independently associated with the risk of SCD or major ventricular arrhythmias together with LV dilatation, older age, advanced NYHA functional class, frequent ventricular ectopic activity, and non-sustained ventricular tachycardia. Clinical implications “Septal LGE together with LV dilatation, age, advanced disease, and frequent and repetitive ventricular arrhythmias were powerful predictors of major arrhythmic events,” said Castrichini, De Luca and colleagues, adding that the findings from the study may prompt new considerations for the clinical management of patients with DCM and NDLVC. “First, LGE appears to be a strong predictor of adverse arrhythmic outcomes independent of LVEF, which emphasizes the need for a systematic CMR-guided characterization because of its prognostic and therapeutic implications,” they said, reiterating that the importance of CMR in the assessment of cardiomyopathies has been recently stated in the 2023 cardiomyopathy guidelines of the ESC. “Our results confirm the importance of a deep characterization of patients with DCM and NDLVC through CMR imaging, on top of the genetic testing, which is particularly relevant when an elusive result is found,” they concluded. Writing in an accompanying editorial comment, John Gorcsan, MD, and Shunsuke Eguchi, MD, PhD, from the Pennsylvania State University College of Medicine, Hershey, said the results of the study will allow better risk stratification of patients with DCM and NDLVC and may impact treatment strategies. “For example, adjustments in therapeutic agents and expanded and refined indications for implanting cardioverter defibrillators. Ultimately, it is hoped that this strategy will lead to improved quality of life and prognosis for patients with HF.” Sources: Castrichini M, De Luca A, De Angelis G, et al. Magnetic Resonance Imaging Characterization and Clinical Outcomes of Dilated and Arrhythmogenic Left Ventricular Cardiomyopathies. J Am Coll Cardiol 2024;83:1841-1851. Gorcsan J, Eguchi S. Predictors of Arrhythmic Outcomes in Patients With Dilated and Nondilated Left Ventricular Cardiomyopathies. J Am Coll Cardiol 2024;83:1852-1854. Image Credit: freshidea – stock.adobe.com