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 RR interval formula:

Where:

• \( RR_{seconds} \) — RR interval in seconds
• \( HR_{bpm} \) — Heart rate in beats per minute

Explanation: Since heart rate is beats per minute, dividing 60 seconds 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 analysis, used for assessing heart rate variability, diagnosing arrhythmias, and determining timing in cardiac pacing.

4. Using the Calculator

Tips: Enter heart rate in beats per minute (normal range 60-100 bpm at rest). The calculator will provide RR interval in both seconds and milliseconds.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal RR interval?
A: At 60 bpm, RR is 1.0 second (1000 ms). At 100 bpm, RR is 0.6 seconds (600 ms). Normal varies with heart rate.

Q2: How is RR interval used in ECG?
A: It determines heart rate and helps identify irregular rhythms. Regular RR intervals suggest normal sinus rhythm.

Q3: What does a variable RR interval indicate?
A: Variable RR may indicate sinus arrhythmia (normal in young people) or pathological arrhythmias like atrial fibrillation.

Q4: How does RR relate to QT interval?
A: QT interval varies with RR. Corrected QT (QTc) accounts for this using formulas like Bazett's.

Q5: Can RR interval predict heart conditions?
A: Abnormal RR patterns may suggest conditions like heart block, atrial flutter, or other arrhythmias.