Purpose: Premature ventricular contractions (PVCs) are common in children even in the absence of structural heart disease or channelopathy. Risk stratification in this subset of children is predicated on clinical symptoms such as syncope, as well as the results of stress test, Holter evaluation, and echocardiogram. Suppression of PVCs with exercise portends a favorable prognostic marker. However, there is paucity of data regarding exercise stress tests variables and PVC characteristics noted on Holter in this population. Our aim is to investigate the association between exercise stress parameters and PVC burden ascertained with a 24 hour Holter in children without a structural heart disease/channelopathy. Methods: In this Institutional Review Board-approved retrospective study, we analyzed the electronic medical records of 447 patients with PVCs collated from the Children’s Hospital Cardiac Database from 1/2000 to 12/2018. Exclusion criteria included the presence of structural heart disease, channelopathy, and incomplete testing protocol. A total of 91 patients who underwent an echocardiogram, maximal stress test, and 24 hour Holter, and had no structural heart disease or channelopathy comprised the study cohort. Maximal stress test was defined as respiratory exchange ratio F0B3 1.05 or peak heart rate > 80% of predicted. Peak oxygen uptake (VO2 in ml/kg/min) during the test is an indicator of maximal aerobic capacity. Other parameters collected were a) Percentage of predicted VO2 (%VO2) based on age, weight, height and gender b) oxygen pulse, c) % oxygen pulse, d) Tidal volume (TV)%, e) forced vital capacity, f) Forced expiratory volume in 1 second (FEV1) and g) Anaerobic threshold (AT). Holter parameters such as PVC burden (%), coupling interval of PVC, and the presence of non-sustained VT were analyzed. Patients were classified into two groups, i.e. < 10% and ≥ 10%, based on PVC burden on Holter monitor. Demographic (age and weight) and exercise stress test derived parameters were compared between the two groups using Student t-test (SPSS version 20.0). P value < 0.05 was considered significant. Results: In our cohort (n=91), PVCs were fully suppressed in 88 (98%) patients during stress test. All patients had normal biventricular size and left ventricular ejection fraction (LVEF ≥ 60%). PVC was noted to be mono morphology in 72(80%) patients. There were no significant differences between the two groups ( < 10% vs. ≥ 10% PVC burden) with respect to demographic or exercise test derived parameters (Table 1). Conclusion: Children with PVCs and no structural heart disease/channelopathy did not demonstrate any objective differences in their exercise capacity or other exercise parameters irrespective of their PVC burden. Normal LVEF and suppression of PVC during exercise was also the norm in this cohort. In such a cohort, aerobic exercise capacity was preserved, even when the PVC burden was 10% or higher.

Comparing demographic and exercise stress test parameters between the two groups; < 10% vs ≥ 10% PVC burden

No statistical significance (p > 0.05) in demographic and exercise stress test parameters between the two groups

Comparing demographic and exercise stress test parameters between the two groups; < 10% vs ≥ 10% PVC burden

No statistical significance (p > 0.05) in demographic and exercise stress test parameters between the two groups

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