Arrhythmic genotypes in dilated cardiomyopathy and risk of advanced heart failure.

Abstract

Certain genetic forms of dilated cardiomyopathy (DCM) entail a higher arrhythmic risk. It is unknown whether DCM patients with high-risk arrhythmic genotypes also develop more advanced heart failure (AHF) complications. AHF events were studied according to DCM genotype. Clinical data from 1203 genotyped DCM patients were collected from 19 Spanish centres. Patients were classified into high-risk arrhythmic genotypes (LMNA, FLNC, desmosomal genes, PLN, TMEM43, RBM20), TTN, other genes, and genotype negative (Gen-). The primary endpoint was a composite of AHF events (ventricular assist device implantation, heart transplant, and AHF-related mortality). The secondary endpoint was a combination of malignant ventricular arrhythmias (MVA). A DCM-causing variant was identified in a high-risk arrhythmic gene in 185 patients (15.4%), 193 (16.0%) had variants in TTN, 134 (11.1%) in other genes, and 691 (57.4%) were Gen-. After a median follow-up of 5.7 years (interquartile range 2.9-9.1 years), AHF events occurred in 45 (24.3%) patients in the high-risk arrhythmic group, while in 25 (18.7%), 25 (13.0%), and 70 (10.1%) patients with other genotypes, TTN, and Gen-, respectively (hazard ratio 1.85, 95% confidence interval 1.31-2.61 for high-risk arrhythmic genes compared with other groups). MVA occurred in 55 patients (29.7%) (hazard ratio 2.52, 95% confidence interval 1.81-3.51 for high-risk genotypes vs other groups). High-risk arrhythmic genotype was the main independent predictor of AHF in multivariate analysis. High-risk arrhythmic genotype and late gadolinium enhancement were independent predictors of MVA. Patients with high-risk arrhythmic genotypes also experience more AHF events, supporting a differential therapeutic approach in this group of patients beyond sudden death prevention.