Malabsorption in infants with congenital heart disease under diuretic treatment.

Intestinal absorption and its relationship to increased total body water was studied in seven infants with congenital heart disease receiving regular diuretics due to congestive heart failure. All infants and six age-matched healthy controls were studied for a 3-d period during which time all food intake was recorded, stools were collected, and total body water content (TBW) and extracellular water were measured. All the anthropometric measurements were lower in the infants with congenital heart disease compared with healthy controls. Energy and fat excretion in the stools were significantly increased in the group of patients, but when expressed as a percentage of daily caloric intake or as a percentage of the specific intake (e.g. fat excretion/fat intake x 100), no statistical differences were found. TBW as a percentage of body weight was increased in our patients compared with our controls (84.95 +/- 5.82% versus 68.65 +/- 4.60%; p = 0.01) and so was extracellular water as a percentage of predicted (200.0 +/- 18.6% versus 100.9 +/- 7.2%; p = 0.001). A positive correlation was found between energy and fat excretion as a percentage of the intake and TBW as a percentage of predicted; energy and fat malabsorption did not exceed 8% in the patients with the highest body water content (120% of predicted). It is concluded that malabsorption is not a significant factor in failure to thrive of patients with congenital heart disease who are receiving regular diuretics. Based on the significant negative correlation between excess body water and fat and calorie absorption, however, it is suggested to monitor TBW in patients who fail to gain weight.