High Burden Ventricular Ectopy > 10% in Children with Structurally Normal Hearts: Investigating the Association of Ventricular Ectopy Frequency, Holter and ECG Findings, and Ventricular Dysfunction.

Frequent ventricular ectopy (VE) ≥ 10% in children with structurally normal hearts and the development of ventricular dysfunction is not well described. We aim to describe frequent VE ≥ 10% in children with structurally normal hearts and characterize the development of dysfunction. Patients with VE burden ≥ 10% on 24-h Holter performed between 2010 and 2019 were included in this retrospective review. Patients with structural heart disease and cardiomyopathy preceding the onset of VE were excluded. Medical records, electrocardiogram, Holter, and transthoracic echocardiogram data were analyzed. Patients were classified based on maximum VE burden on Holter ("frequent" 10-29% versus "very frequent" ≥ 30%), presence of runs of VE, VE morphology on ECG, coupling interval, and development of dysfunction. Two hundred thirty-four patients met inclusion criteria, 187 with frequent VE and 47 with very frequent VE. Seventeen (7%) patients developed ventricular dysfunction, the majority of whom had mild dysfunction. Very frequent VE > 30% and non-sustained ventricular tachycardia (NSVT) on Holter were associated with dysfunction. There was no association between coupling interval or prematurity index and dysfunction. Ventricular dysfunction is uncommon in children with structurally normal hearts and frequent VE burden > 10%, though VE burden > 30% and presence of NSVT were associated with dysfunction. Previously described characteristics to delineate higher risk VE based on coupling interval were not associated with dysfunction.