Key Points
- To establish normative 24-hour dynamic electrocardiographic reference values for heart rate, atrioventricular conduction time (PR interval), and QT intervals in healthy children.
- Dynamic 24-hour ECG Holter monitoring performed in 32 healthy children (20 boys, 12 girls; aged 6–11 years) without evidence of heart disease on clinical and noninvasive instrumental exams.
- Evaluated variations in heart rate (HR), PR intervals, absolute QT intervals, and rate-corrected QT intervals (QTc) across day and night periods.
- Mean 24-hour heart rate was 87 ± 10 beats/min (daytime mean 93 ± 10 beats/min vs. nighttime mean 74 ± 11 beats/min), ranging from a minimum of 61 ± 10 beats/min to a maximum of 160 ± 20 beats/min.
- PR interval duration was inversely related to heart rate, averaging 154 ± 10 ms at HR ≤60 beats/min and shortening to 102 ± 12 ms at HR ≥120 beats/min (overall range 85–180 ms).
- QT intervals averaged 389 ± 9 ms at HR ≤60 beats/min and shortened to 261 ± 10 ms at HR >120 beats/min, with corresponding mean QTc values ranging between 388 ± 8 ms and 403 ± 14 ms.
Structured PICO
PPopulation32 healthy children (20 males and 12 females, age range 6-11 years old), without heart disease
IIntervention24-hour Holter monitoring
OOutcomeAtrioventricular conduction time (PR), heart rate (HR), and QT interval patternssurrogate
The study provides normative data for heart rate, PR, and QT intervals in healthy children aged 6-11 years using 24-hour Holter monitoring.