Median PR Duration

**Semantic type:** Quantitative Concept

**Definition:** A measurement of the median duration (time) of the PR interval, obtained from a set of measurements of the PR interval. The PR interval is defined as the time from the beginning of the P wave (representing the onset of atrial depolarization) to the beginning of the R wave (representing the onset of ventricular depolarization). In some cases, a Q wave will precede the R wave, in which case the PR interval is measured from the beginning of the P wave to the beginning of the Q wave.