P2A157: Caught in the Act: A Detailed Analysis of Event Monitoring in the Pediatric Population

Background: Event monitors are commonly used to evaluate patients with and without congenital heart disease (CHD) for possible arrhythmias. Data regarding the utility of these monitors in the current era are limited.

Methods: This was a retrospective review of patients undergoing first time event monitor evaluation at Texas Children’s Hospital from 2017-2020. Thirty-day event monitor reports and tracings from the same vendor were reviewed by an electrophysiologist (EP). The primary outcome was an EP-confirmed critical event defined as SVT (re-entrant, atrial tachycardia, atrial flutter, and atrial fibrillation), VT, AV block, pauses greater than 3 seconds, and syncope. Demographics, monitoring indication, cardiac history, family history, and ordering provider data were collected. Differences by characteristics were evaluated using univariable logistic regression; then, a multivariable model was generated using backward elimination.

Results: Among 2116 patients who underwent first time event monitoring (59% female), median age at monitoring was 13 years (IQR 8, 16). The median number of events sent per monitor was 6 (IQR 3-12). 258 patients had tracings flagged as critical events (12%), 212 of which were confirmed by an EP physician (10%). Among patients with EP-confirmed critical events, 45% had SVT, 31% had VT, 3% had AV block, 6% had pauses, and 15% had symptomatic syncope with no rhythm finding. Amongst the 212 patients with critical events, 119 (56%) required intervention with medical management, ablation, or device placement. Compared to 2017, event monitoring usage increased by 31% in 2020 (p < 0.001), although proportion of monitors with critical events did not change (p=0.16). Multivariable analysis identified complex CHD (OR 1.9, 95%CI 1.2-3.0, p=0.010) and history of cardiomyopathy (OR 1.9, 95%CI 1.0-3.5, p=0.038) as factors associated with critical events. In addition, event monitors ordered by an EP were associated with increased critical events (OR 1.6, 95%CI 1.2-2.1, p=0.003) compared to those ordered by a general cardiology provider.

Conclusion: Event monitoring is being increasingly utilized in the pediatric and adult congenital sphere. Confirmed critical events were captured in 10% of patients in our cohort. Just over one-half of patients (56%) with critical events required intervention. Risk factors for critical events include EPs as ordering providers, complex CHD, and cardiomyopathy. Given the significant time and cost for these monitors, judicious use is advised.