AFib Heart Rate Calculator
Calculate ventricular rate for irregular rhythms using the 6-second or 10-second strip method.
6 Seconds (Standard Strip)
10 Seconds (Full EKG)
15 Seconds
60 Seconds (Full Minute)
Estimated Ventricular Rate
— BPM
Medical Disclaimer: This tool is for educational purposes only. Calculations in Atrial Fibrillation are estimates due to the "irregularly irregular" nature of the rhythm. Always consult a healthcare professional for clinical diagnosis.
How to Calculate Heart Rate in Atrial Fibrillation
Calculating the heart rate (specifically the ventricular response) in Atrial Fibrillation (AFib) differs from calculating a regular sinus rhythm. In a normal rhythm, you can use the "300-150-100" method or count small boxes between two R-waves. However, because AFib is irregularly irregular, the distance between beats changes constantly.
To get an accurate average heart rate in AFib, you must use the Time Window Method:
- The 6-Second Method: Count the number of QRS complexes (the spikes) on a 6-second EKG strip and multiply by 10.
- The 10-Second Method: Count the number of complexes on a 10-second EKG strip and multiply by 6.
Understanding the Results
The goal of treating AFib is often "Rate Control." Depending on the patient's condition, the target heart rate may vary:
- Controlled Rate: Typically between 60 and 100 BPM.
- Rapid Ventricular Response (RVR): A heart rate over 100-110 BPM. This often requires medical intervention to prevent heart muscle fatigue (tachycardia-induced cardiomyopathy).
- Bradycardia: A heart rate below 60 BPM, which may occur due to medication over-titration or underlying conduction issues.
Example Calculation
If you have a 6-second EKG strip and you count 9 R-waves within that window:
Formula: 9 beats × 10 = 90 BPM.
In this example, the patient has a controlled ventricular response. If you counted 15 beats in that same 6 seconds, the rate would be 150 BPM, signifying Atrial Fibrillation with RVR.