Twenty four hour intermittent, ambulatory blood pressure monitoring.

Blood pressure and heart rate were measured every 30 minutes during the day and every hour during the night in 43 children (20 girls and 23 boys, aged 10 to 16) with a portable automated monitor. The apparatus was better accepted in girls than in boys, and the failure rate was lower during the day. The overall failure rate was 22%, which corresponds with comparable studies in adults. During the night blood pressure and heart rate fell by 10% and 14% of the daytime values, respectively. Mean (SD) blood pressure was significantly higher in boys than in girls (126/72 (17/8) v 109/64 (9/5) mm Hg) and measurements correlated positively with age, body weight, and height of the subjects. Heart rate was not significantly influenced by gender or age. A positive correlation between heart rate and blood pressure was found when expressed as standard normal deviations or hourly variations. In children intermittent monitoring of ambulatory blood pressure and heart rate is a suitable method for measuring individual diurnal patterns.