High Mid-Flow to Vital Capacity Ratio and the Response to Exercise in Children With Congenital Heart Disease.
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.
Pediatric Pulmonary Unit Daphna.Vilozni@sheba.health.gov.il.
Daphna
D
Vilozni
Pediatric Pulmonary Unit.
Maria Rosario
MR
Alcaneses-Ofek
Lifestyle, Exercise, and Nutrition Clinic.
Ronen
R
Reuveny
Lifestyle, Exercise, and Nutrition Clinic.
Omer
O
Rosenblum
Lifestyle, Exercise, and Nutrition Clinic.
Omri
O
Inbar
Edmond J Safra International Congenital Heart Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Uriel
U
Katz
Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Tomer
T
Ziv-Baran
Lifestyle, Exercise, and Nutrition Clinic.
Gal
G
Dubnov-Raz
D000293:Adolescent; D002648:Child; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005540:Forced Expiratory Flow Rates / Q000502:physiology*; D006330:Heart Defects, Congenital / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D015656:Respiratory Mechanics / Q000502:physiology; D012189:Retrospective Studies; D013147:Spirometry; D014797:Vital Capacity / Q000502:physiology*
congenital heart disease; dysanapsis; exercise testing; pulmonary function test