Calculating Heart Rate in Irregular Rhythm

Irregular Heart Rate Calculator

Professional EKG/ECG 6-Second Strip Method

Count every 'R' wave in the selected time period.
Usually 6 or 10 seconds for standard EKGs.
Estimated Mean Heart Rate:
— BPM
Normal

Understanding Heart Rate in Irregular Rhythms

Calculating a heart rate when the rhythm is regular is simple—you can use the "300 Method" (300 divided by the number of large squares between R-waves). However, when a patient has an irregular rhythm like Atrial Fibrillation (AFib), the distance between beats (the RR interval) varies constantly. In these cases, the standard methods will give you a different heart rate for every single beat.

The 6-Second Strip Method

The gold standard for calculating a mean heart rate in irregular rhythms is the 6-second rule. Since heart rate is defined as beats per minute (60 seconds), counting the beats in a 6-second window and multiplying by 10 provides a reliable average.

  • Step 1: Identify a 6-second section on the EKG paper (usually 30 large squares at standard 25mm/sec speed).
  • Step 2: Count the number of QRS complexes (the spikes) within those 30 squares.
  • Step 3: Multiply that number by 10.

Interpretation of Results

Rate Range Classification
Below 60 BPM Bradycardia
60 – 100 BPM Normal Range
Above 100 BPM Tachycardia
Medical Disclaimer: This tool is for educational purposes only. Clinical decisions should be made by qualified healthcare professionals using full diagnostic equipment and clinical assessment.
function calculateIrregularHR() { var qrs = document.getElementById('qrsCount').value; var seconds = document.getElementById('stripSeconds').value; var resultArea = document.getElementById('hrResultArea'); var valueDisplay = document.getElementById('hrValueDisplay'); var classDisplay = document.getElementById('hrClassification'); if (!qrs || qrs <= 0 || !seconds || seconds <= 0) { alert("Please enter valid positive numbers for both fields."); return; } // Calculation: (Beats / Seconds) * 60 = Beats Per Minute var bpm = Math.round((parseFloat(qrs) / parseFloat(seconds)) * 60); resultArea.style.display = 'block'; valueDisplay.innerText = bpm + " BPM"; var classification = ""; var color = ""; if (bpm 100) { classification = "Tachycardia"; color = "#d9534f"; // Red } else { classification = "Normal Rate"; color = "#28a745"; // Green } classDisplay.innerText = classification; classDisplay.style.color = color; // Smooth scroll to result resultArea.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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