What does the time between atrial and ventricular depolarization refer to?

The time between atrial and ventricular depolarization is referred to as the P-R interval. This interval represents the duration from the beginning of atrial depolarization (indicated by the P wave on an ECG) to the beginning of ventricular depolarization (indicated by the QRS complex). It is crucial for understanding the time it takes for electrical impulses to travel from the atria to the ventricles, providing important information about the conduction system of the heart.

A prolonged P-R interval can indicate issues such as first-degree heart block, where the conduction through the atrioventricular (AV) node is delayed. It is a key metric used in cardiac diagnoses and helps clinicians assess the state of the heart's electrical activity.

In contrast, the QT interval measures the total time for ventricular depolarization and repolarization, the ST segment represents the period between the end of ventricular depolarization and the beginning of repolarization, and the T wave duration reflects the period of ventricular repolarization. Each of these other components provides distinct and valuable information but does not specifically indicate the interval between atrial and ventricular depolarization like the P-R interval does.