How is the R-R interval measured using a caliper?

The R-R interval is measured from one R wave to the next R wave on an electrocardiogram (ECG). This interval is crucial as it represents the time between successive ventricular contractions, allowing healthcare professionals to assess heart rate and rhythm. The R wave is the prominent upward deflection observed in the QRS complex, and since it indicates the depolarization of the ventricles, measuring the time between R waves provides accurate insights into the heart's electrophysiological activity. By using a caliper to measure this interval, clinicians can determine the heart rate (by calculating beats per minute) and evaluate for any arrhythmias that might impact patient care.

Other interval measurements such as from T waves, P waves, or Q waves do not reflect the time between ventricular depolarization events, which is essential for evaluating heart function. Thus, focusing on the R wave is the standard practice in ECG analysis.