1. What is RR Interval?

The RR interval is the distance between consecutive R waves on an ECG. It represents the time between heartbeats and is used to calculate heart rate and assess heart rhythm.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• Distance between R waves — Measured in millimeters (mm)
• Paper speed — Typically 25 mm/s or 50 mm/s

Heart Rate Calculation: Heart rate (bpm) = 60 / RR interval (seconds)

3. Importance of RR Interval

Details: RR interval measurement is essential for determining heart rate, diagnosing arrhythmias, and assessing heart rate variability.

4. Using the Calculator

Tips: Measure the distance between two consecutive R peaks on ECG paper, enter the value in mm, and select the paper speed used during ECG recording.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal RR interval?
A: At normal heart rate (60-100 bpm), RR interval is 0.6-1.0 seconds. Shorter intervals indicate tachycardia, longer intervals indicate bradycardia.

Q2: How do I measure RR interval on ECG paper?
A: Count the number of small squares (1 mm) between R waves. Each small square represents 0.04 seconds at 25 mm/s.

Q3: Why are there different paper speeds?
A: 25 mm/s is standard, while 50 mm/s provides more detailed waveform analysis by stretching the ECG horizontally.

Q4: What if RR intervals vary?
A: Variable RR intervals may indicate arrhythmias like atrial fibrillation. Measure several intervals and calculate average.

Q5: Can I use this for irregular rhythms?
A: For irregular rhythms, measure several RR intervals and calculate average heart rate from multiple measurements.