PR interval

Interpretation

• Duration
• * A long PR interval indicates a slowing of conduction between the atria and ventricles, usually due to slow conduction through the atrioventricular node. This is known as first degree heart block. Prolongation can be associated with fibrosis of the AV node, high vagal tone, medications that slow the AV node such as beta-blockers, hypokalemia, acute rheumatic fever, or carditis associated with Lyme disease.
• * A short PR interval may be associated with a Pre-excitation syndromes such as Wolff–Parkinson–White syndrome or Lown–Ganong–Levine syndrome, and also junctional arrhythmia like atrioventricular reentrant tachycardia or junctional rhythm.
• * A variable PR interval may indicate other types of heart block.
• PR segment depression may indicate atrial injury or pericarditis.

  Related pages

• P wave