Which ECG interval measures the time from the start of atrial depolarization to the start of ventricular depolarization?

The PR interval measures the time from the beginning of atrial depolarization to the beginning of ventricular depolarization. This interval encompasses the time it takes for the electrical impulse to travel from the atria through the AV node and into the ventricles. Analyzing the PR interval is crucial for assessing the conduction between the atria and ventricles and can provide insights into potential atrioventricular (AV) block or other conduction abnormalities.

The QT interval reflects the total time for ventricular depolarization and repolarization, while the ST segment represents the period when the ventricles are depolarized and is used to assess ischemia or infarction. The RR interval measures the time between two successive R waves and is often used for heart rate calculations. Therefore, among all the intervals listed, the PR interval is specifically and accurately defined as the measure of time between atrial and ventricular depolarization.