The PR interval is measured from the onset of atrial depolarization (P wave) to the beginning of ventricular depolarization (QRS complex).
- 1% of population
- Each P wave has an associated QRS
- PR interval > 0.2 seconds ( 200ms = five small squares )
- First-degree block may progress to other forms of heart block.
- High vagal tone in athletes with slow resting heart rates
- Rheumatic fever, Congenital heart disease
- Ischaemic heart disease, Digoxin toxicity, Amyloid
- Aortic root abscess, Myocarditis, SAN disease
- Low K, Diphtheria, Sarcoidosis, Lyme disease,
- None may be needed
- Acute setting; ECG, U&E, LFTS, TFTs
- Usually benign and physiological and not require treatment.
- Review medications and causes
- Will depend upon symptoms and observations.