High mid-flow to vital capacity ratio and the response to exercise in children with congenital heart disease

Daphna Vilozni*, Maria Rosario Alcaneses-Ofek, Ronen Reuveny, Omer Rosenblum, Omri Inbar, Uriel Katz, Tomer Ziv-Baran, Gal Dubnov-Raz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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, VO2, VCO2, 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.

Original languageEnglish
Pages (from-to)1629-1635
Number of pages7
JournalRespiratory Care
Issue number12
StatePublished - 1 Dec 2016


  • Congenital heart disease
  • Dysanapsis
  • Exercise testing
  • Pulmonary function test


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