1. What is the RR Interval?

The RR interval is the time between successive R waves on an electrocardiogram (ECG). It represents the duration of one cardiac cycle and is inversely proportional to heart rate.

2. How Does the Calculator Work?

The calculator uses the MDCalc formula:

Where:

• \( RR \) — RR interval in seconds
• \( HR \) — Heart rate in beats per minute (bpm)

Explanation: Since heart rate is measured in beats per minute (60 seconds), dividing 60 by the heart rate gives the duration of one cardiac cycle in seconds.

3. Importance of RR Interval Calculation

Details: RR interval is fundamental in ECG interpretation, helping to determine heart rate, identify arrhythmias, and assess heart rate variability.

4. Using the Calculator

Tips: Enter heart rate in beats per minute (bpm). The value must be valid (HR > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is a normal RR interval?
A: At 60 bpm, RR interval is 1.0 second. Normal range is typically 0.6-1.2 seconds (50-100 bpm).

Q2: How is RR interval used in ECG?
A: It's used to calculate heart rate, detect irregular rhythms, and assess heart rate variability.

Q3: What does a short RR interval indicate?
A: Short RR intervals indicate tachycardia (fast heart rate), while long intervals indicate bradycardia (slow heart rate).

Q4: Can RR interval vary?
A: Yes, normal variation with respiration (sinus arrhythmia) is common, especially in younger individuals.

Q5: How accurate is this calculation?
A: This provides the average RR interval. Actual ECG measurements may show beat-to-beat variations.