PR interval

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.

Variations in the PR interval can be associated with certain medical conditions:

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