Predictive value of ambulatory ECG monitoring for malignant arrhythmic events in genetic dilated cardiomyopathy

Aims Evaluate the prognostic significance of arrhythmias and conduction disorders on ambulatory ECG in recently diagnosed genetic vs. non-genetic dilated cardiomyopathy (DCM). Objective To compare the prevalence of abnormalities on ambulatory ECG monitoring between genetic and non-genetic DCM patients and evaluate the predictive value for malignant ventricular adverse events (MVAEs). Methods and results Clinical and ambulatory ECG data were collected from 354 genotyped DCM probands, with a median follow-up of 8 years (IQR: 5-9 years). The malignant ventricular adverse event was defined as ventricular fibrillation, sustained ventricular tachycardia, anti-tachy pacing, appropriate device therapy, or sudden cardiac death. C-statistics assessed the predictive performance of the regression models. In total, 123 (35%) patients carried a (likely) pathogenic variant. Abnormalities on ambulatory ECG were more frequent in genetic DCM patients (80%) compared to non-genetic DCM (67%; P = 0.013). Permanent atrial fibrillation (perAF), paroxysmal supraventricular tachycardia (parox-SVT), and non-sustained ventricular tachycardia (NSVT) were more frequent in genetic DCM patients (P = 0.041, <0.001, and <0.001). Structural cardiac parameters showed minimal group differences. Using Cox proportional hazard analyses to predict MVAE, ambulatory ECG variables (perAF, AV-block, NSVT, >500 premature ventricular complexes (PVCs)/24 h) had an area under the curve (AUC) of 0.768 in genetic and 0.628 in non-genetic DCM patients (P = 0.044). The premature ventricular complex burden was only predictive for MVAE in genetic DCM. Adding clinical variables provided little incremental predictive value for genetic vs. non-genetic DCM (AUC Delta+0.004 vs. Delta+0.150, respectively). Conclusion Ambulatory ECG monitoring abnormalities are prevalent in genetic DCM patients. In contrast to non-genetic DCM patients, ambulatory ECG parameters have an important predictive value to determine the risk of MVAE in genetic DCM patients.[GRAPHICS]