RT Journal Article SR Electronic T1 High Mid-Flow to Vital Capacity Ratio and the Response to Exercise in Children With Congenital Heart Disease JF Respiratory Care FD American Association for Respiratory Care SP 1629 OP 1635 DO 10.4187/respcare.04811 VO 61 IS 12 A1 Vilozni, Daphna A1 Alcaneses-Ofek, Maria Rosario A1 Reuveny, Ronen A1 Rosenblum, Omer A1 Inbar, Omri A1 Katz, Uriel A1 Ziv-Baran, Tomer A1 Dubnov-Raz, Gal YR 2016 UL http://rc.rcjournal.com/content/61/12/1629.abstract AB BACKGROUND: Pulmonary mechanics may play a role in exercise intolerance in patients with congenital heart disease (CHD). A reduced FVC volume could increase the ratio between mid-flow (FEF25-75%) and FVC, which is termed high dysanapsis. The relationship between high dysanapsis and the response to maximum-intensity exercise in children with CHD had not yet been studied. The aim of this work was to examine whether high dysanapsis is related to the cardiopulmonary response to maximum-intensity exercise in pediatric subjects with CHD.METHODS: We retrospectively collected data from 42 children and adolescents with CHD who had either high dysanapsis (ratio >1.2; n = 21) or normal dysanapsis (control) (n = 21) as measured by spirometry. Data extracted from cardiopulmonary exercise test reports included peak values of heart rate, work load, V̇O2, V̇CO2, and ventilation parameters and submaximum values, including ventilatory threshold and ventilatory equivalents.RESULTS: There were no significant differences in demographic and clinical parameters between the groups. Participants with high dysanapsis differed from controls in lower median peak oxygen consumption (65.8% vs 83.0% of predicted, P = .02), peak oxygen pulse (78.6% vs 87.8% of predicted, P = .02), ventilatory threshold (73.8% vs 85.3% of predicted, P = .03), and maximum breathing frequency (106% vs 121% of predicted, P = .035). In the high dysanapsis group only, median peak ventilation and tidal volume were significantly lower than 80% of predicted values.CONCLUSIONS: In children and adolescents with corrected CHD, high dysanapsis was associated with a lower ventilatory capacity and reduced aerobic fitness, which may indicate respiratory muscle impairments.