In the field of cardiology, the PR segment refers to the portion of the electrocardiogram (ECG) that represents the time between the depolarization of the atria (atrial contraction) and the depolarization of the ventricles (ventricular contraction). The PR segment is typically isoelectric, meaning it is at the same electrical level as the baseline of the ECG. It follows the P wave and precedes the QRS complex. The normal duration of the PR segment is between 0.12 to 0.20 seconds. Abnormalities in the PR segment can indicate various cardiac conditions, including but not limited to: 1. Prolonged PR segment: This can be seen in first-degree atrioventricular (AV) block or with the use of certain medications that affect the AV node conduction, such as beta-blockers or calcium channel blockers. 2. Shortened PR segment: This may occur in conditions that cause rapid conduction through the AV node, such as Wolff-Parkinson-White (WPW) syndrome. Abnormalities in the PR segment can also be associated with other conditions like: - Pericarditis: Inflammation of the pericardium, which can affect the ECG waveforms. - Atrial ischaemia: Insufficient blood supply to the atria, which can also alter the ECG. It's important for healthcare professionals to interpret the PR segment within the context of the entire ECG and the patient's clinical presentation to determine the significance of any abnormalities. read more >>

The PR segment is the flat, usually isoelectric segment between the end of the P wave and the start of the QRS complex. PR segment abnormalities occur in two main conditions: Pericarditis. Atrial ischaemia.read more >>