What does the R-R interval measure?

The R-R interval is a crucial measurement in cardiology, particularly in the context of electrocardiograms (ECGs). It specifically measures the duration between two consecutive R waves, which represent the depolarization of the ventricles that leads to ventricular contraction, marking the beginning of one heartbeat to the beginning of the next.

The correct answer emphasizes that the R-R interval directly correlates to the time between heartbeats, making it essential for determining the heart rate and identifying rhythm abnormalities. By analyzing the R-R interval, clinicians can assess overall heart function, rhythm stability, and even calculate the average heart rate by determining the number of R-R intervals over a specific time frame.

In contrast, while other measurements such as those referring to atrial depolarization or the S-T wave are components of the ECG, they do not pertain specifically to the timing between heartbeats like the R-R interval does.