Irregular Heart Rate (ECG) Calculator
Method: This tool uses the 6-second strip method, which is the gold standard for calculating heart rate in patients with irregular rhythms such as Atrial Fibrillation (AFib). Unlike the "300 method," this calculation provides a more accurate average beats per minute (BPM).
How to Calculate Irregular Heart Rate on an ECG
Calculating the heart rate on an electrocardiogram is straightforward when the rhythm is regular. You can simply divide 300 by the number of large squares between R-waves. However, for irregular rhythms (where the distance between R-waves varies), this method fails because it only measures one specific interval.
The 6-Second Method Explained
The 6-second method is the most reliable way to determine the heart rate for rhythms like atrial fibrillation, premature ventricular contractions (PVCs), or sinus arrhythmia. On standard ECG paper moving at 25 mm/sec:
- One large square = 0.2 seconds.
- Five large squares = 1 second.
- 30 large squares = 6 seconds.
Steps to Calculate:
- Obtain a 6-second strip of the ECG (30 large boxes).
- Count the number of QRS complexes (the spikes or R-waves) within that 6-second interval.
- Multiply the number of complexes by 10 to get the beats per minute (BPM).
Calculation Examples:
Example A: You count 8 QRS complexes in a 6-second strip.
Calculation: 8 x 10 = 80 BPM.
Example B: In a longer 10-second rhythm strip, you count 15 complexes.
Calculation: (15 / 10) x 60 = 90 BPM.
Disclaimer: This calculator is for educational purposes only. Always consult with a qualified healthcare professional or cardiologist for medical diagnosis and ECG interpretation.