Hosamabout 1 year ago

PR interval

A long PR interval (of over 200 ms) may indicate a first degree heart block. Prolongation can be associated with hypokalemia, acute rheumatic fever, or carditis associated with Lyme disease. A short PR interval may indicate a pre-excitation syndrome via an accessory pathway that leads to early activation of the ventricles, such as seen in Wolff-Parkinson-White syndrome. A variable PR interval may indicate other types of heart block. PR segment depression may indicate atrial injury or pericarditis. Variable morphologies of P waves in a single ECG lead is suggestive of an ectopic pacemaker rhythm such as wandering pacemaker or multifocal atrial tachycardia.