O0015: Exercise Testing in Pediatric Patients with Pacemakers Can Improve Activity Related Symptoms

Background: Pacemakers are important tools in pediatric patients with conduction disease though some patients still have symptoms with activity after implantation. Exercise stress tests (ESTs) provide an objective way to assess pacemaker settings that may influence exercise related symptoms. Our objective was to assess the safety and utility of EST in pediatric patients with pacemakers

Methods: Retrospective chart review of all pediatric patients with pacemakers (aged 6-20 yrs) followed in our device clinic who underwent an EST with 1 year follow up, between 01/2018 - 1/2021. Patients who presented for a problem-focused visit, had cognitive and/or physical limitations, or were deemed high risk for EST were excluded.

Results: 116 patients were included in this study. 37 patients (31.9%) had pacemaker changes related to EST (Gp A) and 79 patients (68.1%) did not (Gp B). Pacemaker changes related to the EST were defined as changes in rate response and timing. There were no significant differences between Gp A and Gp B based on age, weight, presence of structural heart disease (45.6% vs. 55.7%), presence of dual lead pacemaker (78.4% vs. 82.2%), or EP Diagnosis ((congenital heart block (35.1% vs. 41.8%), surgical heart block (37.8% vs. 27.8%), and sick sinus syndrome (21.6% vs. 22.8%)). There were no significant differences between Gp A and Gp B for percent predicted peak VO2 (80.4% vs. 79.9%, p=0.50), RER (1.1 vs. 1.1, p=0.93), or percent predicted max oxygen pulse (115.9% vs. 107.9%, p=0.71). Gp A had a lower percent predicted max HR than Gp B (72.9% vs. 79.5%, p=0.01). On 1 year follow up visit, Gp A was more likely to have improvement in exercise related symptoms (18.9%, vs. 8.9%), however flat or blunted heart rate histograms persisted on follow up despite pacemaker changes (29.7% in Gp A, 20.3% in Gp B). No adverse events occurred during EST.

Conclusion: In pediatric patients with pacemakers, EST is safe and may identify changes that improve exercise-related symptoms, despite no significant change in overall heart rate histograms. Symptoms that persist after programming changes may warrant further testing.