The Effect Of Pre- Excitation Syndrome On Exercise Parameters In Pediatric Patients

Pre-excitation is characterized by presystolic depolarization and contraction of ventricular myocardium via an accessory atrioventricular (AV) connection bypassing the AV node. Left ventricular (LV) contractile dyssynchrony and chronic dysfunction can result, potentially impacting exercise capacity. Aims: To investigate the effect of pre-excitation on cardiopulmonary function and exercise parameters in the pediatric population. METHODS: Sixteen patients with pre-excitation (10 males) with average age of 12.8 ± 2.9 years and average BMI%tile of 62.6 ± 29.3 were assessed between May 2021 and October 2023. Cardiopulmonary Exercise Test (CPET) and Echocardiography were completed. RESULTS: Echocardiography revealed normal LV function for all patients. All participants achieved maximal effort on CPET. Peak oxygen uptake (peak V̇O2 %predicted) was normal 86.3 ± 23.4% (5/16 had peak V̇O2 < 82%pred). Anaerobic Threshold (AT, as % of peak V̇O2) was normal 41.1 ± 10.6% (6/16 had AT <40%). Peak O2 pulse (V̇O2/HR %pred) was normal (86.5 ± 33.9%) with normal curve. V̇E/V̇CO2 slope and lowest V̇E/V̇CO2, Oxygen saturation, FVC (Forced vital capacity) and FEV1 (Forced expiratory volume in one second) pre, during and post exercise were normal. Breathing reserve was normal for 14/16 of the patients. CONCLUSIONS: Exercise capacity was normal for pre-excitation pediatric patients. No cardiac limitation was demonstrated in any of the pre-excitation patients. Some patients had lower than recommended exercise capacity (V̇O2 and AT). Larger studies are needed to assess pathophysiologic effects of pre-excitation on exercise capacity.