Calculate Rate Ecg

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ECG Heart Rate Calculator

.calculator-wrapper { font-family: sans-serif; border: 1px solid #ccc; padding: 20px; border-radius: 8px; max-width: 500px; margin: 20px auto; box-shadow: 0 2px 4px rgba(0,0,0,0.1); } .calculator-wrapper h2 { text-align: center; margin-bottom: 20px; color: #333; } .input-group { margin-bottom: 15px; display: flex; flex-direction: column; } .input-group label { margin-bottom: 5px; font-weight: bold; color: #555; } .input-group input { padding: 10px; border: 1px solid #ddd; border-radius: 4px; font-size: 16px; } button { display: block; width: 100%; padding: 12px; background-color: #007bff; color: white; border: none; border-radius: 4px; font-size: 18px; cursor: pointer; transition: background-color 0.3s ease; } button:hover { background-color: #0056b3; } #result { margin-top: 20px; padding: 15px; background-color: #e9ecef; border: 1px solid #ced4da; border-radius: 4px; text-align: center; font-size: 18px; font-weight: bold; color: #333; } function calculateHeartRate() { var rRInterval = parseFloat(document.getElementById("rRInterval").value); var calibrationFactor = parseFloat(document.getElementById("calibrationFactor").value); var qrsDuration = parseFloat(document.getElementById("qrsDuration").value); var resultDiv = document.getElementById("result"); resultDiv.innerHTML = ""; // Clear previous result if (isNaN(rRInterval) || rRInterval 0) { // If the calibration factor is in seconds per mm, and we have R-R interval in seconds // we can infer the number of large boxes (300 rule approximation) var largeBoxes = rRInterval / calibrationFactor; if (largeBoxes > 0) { // This is a common approximation using large boxes var alternativeHeartRate = 300 / largeBoxes; // We can display both or choose one. For simplicity, let's use the direct calculation // and mention the approximation is possible. } } // Displaying QRS duration is usually for rhythm analysis, not direct HR calculation // but we can check if it's within normal limits if provided. if (!isNaN(qrsDuration) && qrsDuration > 0) { if (qrsDuration > 0.12) { // Typical upper limit for QRS duration is 0.12 seconds resultDiv.innerHTML += "Note: QRS duration is prolonged (greater than 0.12s)."; } } resultDiv.innerHTML = "Estimated Heart Rate: " + heartRate.toFixed(2) + " bpm"; }

Understanding ECG and Calculating Heart Rate

An electrocardiogram (ECG or EKG) is a non-invasive test that records the electrical activity of the heart. It's a crucial diagnostic tool used by healthcare professionals to assess heart rhythm, detect abnormalities, and monitor heart health. The ECG waveform represents the sequence of depolarization and repolarization of the heart's chambers.

Key Components of an ECG Waveform:

  • P wave: Represents atrial depolarization (contraction of the atria).
  • QRS complex: Represents ventricular depolarization (contraction of the ventricles). This is typically the most prominent part of the ECG.
  • T wave: Represents ventricular repolarization (relaxation of the ventricles).

Calculating Heart Rate from an ECG:

One of the simplest and most common calculations from an ECG is the heart rate, measured in beats per minute (bpm). This can be determined by measuring the time interval between consecutive heartbeats.

Method 1: Using the R-R Interval

The R-R interval is the time between two consecutive R waves on the ECG tracing. This interval directly reflects the duration of one cardiac cycle. The formula to calculate heart rate from the R-R interval is:

Heart Rate (bpm) = 60 / R-R Interval (seconds)

For example, if the R-R interval is measured to be 0.8 seconds, the heart rate would be 60 / 0.8 = 75 bpm.

Method 2: Using the Calibration Factor and Grid Paper

Standard ECG paper has a grid. Each small square typically represents 0.04 seconds, and each large square (made of 5×5 small squares) represents 0.20 seconds. If the calibration setting is 25 mm/sec, then 1 mm on the paper represents 0.04 seconds.

A quick estimation method is the "300 method". If the R-R interval is approximately one large box, the heart rate is about 300 bpm. If it's two large boxes, it's about 150 bpm, three large boxes is 100 bpm, four large boxes is 75 bpm, and five large boxes is 60 bpm. This method works best for regular rhythms.

More precisely, if you know the calibration factor (e.g., 0.04 seconds per small box) and measure the R-R interval in terms of these boxes:

Heart Rate (bpm) = 60 / (Number of Small Boxes x 0.04)

Or, if the R-R interval is measured in large boxes (each 0.20 seconds):

Heart Rate (bpm) = 60 / (Number of Large Boxes x 0.20)

Using the calculator above, if you have an R-R interval of 0.8 seconds and a calibration factor of 0.04 sec/mm (which means 1 large box is 5mm or 0.20s), the calculator will directly use the 60 / 0.8 = 75 bpm formula.

Interpreting Results:

A normal resting heart rate for adults is typically between 60 and 100 bpm. Rates below 60 bpm are considered bradycardia, and rates above 100 bpm are considered tachycardia. However, these ranges can vary based on age, fitness level, and other factors.

The QRS duration is also an important measurement. A normal QRS duration is typically less than 0.12 seconds (or 3 small boxes on standard ECG paper). A prolonged QRS duration can indicate issues with the heart's conduction system, such as a bundle branch block.

This calculator provides a quick way to estimate heart rate from an ECG tracing. Always consult with a qualified healthcare professional for a complete interpretation of ECG results.

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