Electrocardiographic ST-segment depression in children with Fontan circulation

Despite successful operation, many patients palliated with a Fontan-type pr ocedure continue to show effort limitation. We previously observed that the se children showed electrocardiographic ST depression during exercise tests . The purpose of the study was to investigate whether electrocardiographic ST depression is a common finding in children with Fontan circulation. Fort y-two children in two groups were examined: group A consisted of 14 patient s who had all undergone a modified Fontan procedure, and group B consisted of 28 children with a structurally normal heart, matched for length, weight and gender to group A. Complete echocardiographic examinations were perfor med in all patients and controls. All 14 patients and all 28 healthy childr en underwent standard 24 h ambulatory electrocardiographic monitoring. All the recordings were analysed by a PC-based Holter system where an analysis of ST changes was performed. Seven patients and 14 matched healthy children were exercised on bicycle ergometers. Four patients and eight matched heal thy children underwent exercise testing by walking/running a treadmill. Ten of 13 patients analysed had significant ST depressions on ambulatory elect rocardiogram (>0.20 mV). Three of the 10 patients with ST depression were o n digoxin. Three patients showed depressions or the ST segment in the elect rocardiogram during exercise, with a maximal depression of 0.20-0.35 mV. No ne of the 28 matched healthy children showed electrocardiographic ST depres sion on the ambulatory 24 h ECG. These findings indicate that ST depression in daily activity is a common finding in children with Fontan circulation.