The PR interval and segment
Let’s talk about PR Interval and Segment.
The PR interval represents the time between the onset of atrial depolarization and the onset of ventricular depolarization and reflects conduction through the AV node.
PR Interval
✅ Normal PR interval: 0.12 - 0.20 sec.
✅ Prolonged PR interval: >0.20 sec.
✅ Short PR interval: <0.12 sec.
The term “PQ interval” is preferred by some EKG lover because it is the period actually measured unless the Q wave is absent.
PR segment
The PR segment is the segment (forgive the redundancy) between the end of the P wave and the start of the QRS complex. Under normal circumstances is usually isolectric.
PR segment elevation
It is considered when ≥0.5 mm.
Causes of PR segment elevation: Atrial ischaemia/infarction, myopericarditis, PE, others.
PR segment depression
It is considered when ≥0.8 mm.
Causes of PR segment depression: Pericardial effusion, atrial ischemia/infarction, myopericarditis, pulmonary embolism, others.
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