Abstract 4141687: Optimal Duration of Ambulatory Monitoring for Detecting Non-Sustained Ventricular Tachycardia (NSVT) in Pediatric and Adult Congenital Heart Disease Patients

Background: The frequency and clinical significance of non-sustained ventricular tachycardia (NSVT) detected on ambulatory monitors in pediatric and congenital heart disease (CHD) patients has not been thoroughly investigated. We sought to examine the prevalence of NSVT, analyze the presence of associated cardiovascular disease, and describe changes in management. Methods: We performed a retrospective cohort study of all patients evaluated in cardiology clinic at Cleveland Clinic who were found to have NSVT on ambulatory Zio monitors (2017 and 2023). Kaplan Meier curves and Cox proportional hazards model were performed to analyze time to NSVT detection and factors associated with detection. Results: Among 2805 patients, 172 (mean age 29 ± 14, 51% male) had NSVT yielding a prevalence of 6% and a mean monitoring duration of 7.5 ± 5.5 days. Cardiac diagnoses were as follows: 98 (57 %) CHD, 44 (26%) structurally normal hearts, 14 (8%) cardiomyopathy, 10 (6%) connective tissue disorder, and 6 (3%) channelopathy. Monitoring indications included symptoms (97, 56%), history of arrhythmias (34, 20%), screening (36, 21%) and others (5, 3%). Mean day of NSVT detection was 4.3 ± 3.7 years without significant difference amongst the various underlying cardiac diagnoses (p = 0.2). Of the patients who had a repeat ambulatory monitor, 39/113 (34%) were found to have NSVT. Management changes were made in 56 (32%) patients: medication change in 46, EP study in 1, implantable loop recorder placement in 4, and ICD placement in 5. Five patients died during the study period with only 1 suspected sudden cardiac death. The likelihood of NSVT detection increased with longer monitoring duration with only 55% of cases detected at 2 days (Figure 1). In a multivariable model, monitoring duration (HR 0.8, 95% CI: 0.77-0.84, p < 0.001) but not underlying diagnosis, age, monitor indication, or single ventricle status, was associated with likelihood of NSVT detection. Conclusions: NSVT is not an uncommon arrhythmia in pediatric and CHD patients with increasing prevalence with longer monitoring duration regardless of underlying cardiac etiology. Although medical management changes based on monitor findings were frequent, sudden death was rare.