Normal PR Interval for a 16-Year-Old Male
The normal PR interval for a 16-year-old male is 120-200 ms. This range represents the normal conduction time from the atria through the atrioventricular node to the ventricles in adolescents of this age.
Normal ECG Intervals by Age
The PR interval varies by age, with specific considerations for adolescents:
- Children <4 years: Normal PR interval typically 90-160 ms
- Children 4-16 years: Normal PR interval typically 90-180 ms
- Adolescents ≥16 years and adults: Normal PR interval typically 120-200 ms 1
Clinical Significance of PR Interval
Normal PR Interval (120-200 ms)
- Indicates proper conduction through the atrioventricular (AV) node
- Represents normal electrical propagation from the atria to the ventricles
Prolonged PR Interval (>200 ms)
- Classified as first-degree AV block
- May be a normal variant in highly trained athletes due to increased vagal tone 1
- In non-athletes, may indicate conduction system disease or medication effect
Short PR Interval (<120 ms)
- May indicate pre-excitation syndromes like Wolff-Parkinson-White syndrome
- Requires further evaluation if accompanied by delta waves
Age-Related Considerations
The PR interval should be interpreted in the context of age-appropriate norms:
- At age 16, adolescents have typically reached adult ECG parameters
- The American College of Cardiology guidelines indicate that by age 16, ECG parameters approach adult values 1, 2
- The "juvenile" ECG pattern (primarily affecting T-wave morphology) typically resolves by age 16 1
Measurement Technique
For accurate PR interval measurement:
- Measure from the beginning of the P wave to the beginning of the QRS complex
- Use lead II for standard measurements when possible
- Consider global intervals (earliest onset to latest offset in all leads) for comprehensive assessment 2
Clinical Implications
Understanding normal PR interval values helps in:
- Distinguishing normal from pathological findings
- Identifying potential conduction abnormalities
- Establishing baseline values for future comparison
For a 16-year-old male, PR intervals between 120-200 ms should be considered normal, while values outside this range may warrant further evaluation depending on clinical context and other ECG findings.