PR interval
From Infogalactic: the planetary knowledge core
In electrocardiography, the PR interval is the period, measured in milliseconds, that extends from the beginning of the P wave (the onset of atrial depolarization) until the beginning of the QRS complex (the onset of ventricular depolarization); it is normally between 120 and 200ms in duration. If a Q wave is measured by EKG, the PR interval is sometimes termed the PQ interval.
Interpretation
Variations in the PR interval can be associated with certain medical conditions:
- Duration
- A long PR interval (of over 200 ms) may indicate a first degree heart block.[1] Prolongation can be associated with hypokalemia, acute rheumatic fever,[2] or carditis associated with Lyme disease.[3]
- A short PR interval (of less than 120ms) may be associated with Wolff–Parkinson–White syndrome, Lown–Ganong–Levine syndrome, or Junctional rhythms.
- A variable PR interval may indicate other types of heart block.[citation needed]
- PR segment depression may indicate atrial injury[4] or pericarditis.[5]
- Variable morphologies of P waves in a single EKG lead is suggestive of an ectopic pacemaker rhythm such as wandering pacemaker or multifocal atrial tachycardia.[citation needed]
References
- ↑ First-Degree Atrioventricular Block at eMedicine
- ↑ http://www.utmb.edu/pedi_ed/core/cardiology/page_40.htm[full citation needed]
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