Abstract:

Objective To explore the evaluation value of the 6-minute walk test (6MWT) on cardiac function in children with postoperative congenital heart disease during follow-up. Methods Children after CHD surgery (complicated or simple CHD) and followed up over 6 months from Children's Hospital of Fudan University were enrolled as CHD group, and healthy children were enrolled for control group, both groups were subgrouped by age at testing: 3-5, -8, -12 and -15 years age-subgroups.The 6MWT and treadmill test (TET) were performed on the same day. The 6-minute walk distance (6MWD), 6-minute walk work (weight multiplied 6MWD), and breath rate (RR), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) before and after 6 MWT were studied. The relationship between 6MWD, 6MWT work and METs was examined. Results ① RR, HR and SBP increased markedly at the termination of the test（P<0.05）, but DBP did not change significantly（P>0.05）in CHD and control groups by all age-groups. No significant difference was observed between CHD and control groups after 6MWT（P>0.05）. ② The 6MWD was shorter in CHD group than that in control group by all age-groups, of them in CHD 3-5 ［(383.7±52.8) vs (404.4±59.0)m］, -8 years age-subgroup ［(383.7±52.8) vs (404.4±59.0) m］ the 6MWD was significantly shorter than that in control age sub-groups (P<0.05), but no difference was found in -12 ［(510.2±78.9) vs (557.6±66.8)m］ and -15 years age-subgroups ［(595.4±89.6) vs (561.9±75.9) m］ between CHD and control subgroups (P>0.05). In the complicated CHD group the 6MWD was shorter than that in the simple CHD subgroup, (405.3±61.3) vs (465.1±109.4) m, P<0.01. The 6-minute walk work was smaller in CHD group than that in control group. In 3-5, -8, -12 and -15 years age-subgroups no difference was found between CHD and control groups (P>0.05). ③ The METs in CHD 3-5 , -8 and -12 years age subgroups were lower than those in the control age subgroups (P<0.05), but no difference was found in -15 age subgroup (P>0.05). In the complicated CHD subgroup the METs were lower but no difference was found between complex and simple CHD subgroup (P>0.05). The 6MWD (r＝0.486, r=0.543，P<0.01）and 6MWT work (r=0.601, r=0.404, P<0.01) had a positive correlation with METs in CHD group and control group, respectively. Conclusions The 6MWT can reflect daily activity ability of the children with postoperative congenital heart disease. Compared to treadmill test it is the one of more effective method in evaluating the cardiac function and more easily be performed, and cost-effective.

Key words: Cardiac function, Children, Congenital heart disease, Six-minute walking test, Treadmill test