Heart Rate Calculation on Ecg

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ECG Heart Rate Calculator

Your calculated heart rate will appear here.

function calculateHeartRate() { var rrInterval = parseFloat(document.getElementById("rrInterval").value); var ecgPaperSpeed = parseFloat(document.getElementById("ecgPaperSpeed").value); var resultDiv = document.getElementById("result"); if (isNaN(rrInterval) || isNaN(ecgPaperSpeed) || rrInterval <= 0 || ecgPaperSpeed <= 0) { resultDiv.innerHTML = "Please enter valid positive numbers for RR interval and ECG paper speed."; return; } // Formula: Heart Rate (bpm) = 60 / RR Interval (seconds) var heartRate = 60 / rrInterval; resultDiv.innerHTML = "Calculated Heart Rate: " + heartRate.toFixed(0) + " bpm"; }

Understanding ECG Heart Rate Calculation

Electrocardiograms (ECG or EKG) are vital diagnostic tools that record the electrical activity of the heart. One of the most common pieces of information derived from an ECG is the heart rate, which tells us how many times the heart is beating per minute (bpm).

How to Calculate Heart Rate from an ECG

There are several ways to calculate heart rate from an ECG tracing, but a common and straightforward method relies on the R-R interval. The R-R interval is the time between two consecutive R waves on the ECG, which represent the peak of ventricular depolarization. This interval directly corresponds to the duration of one cardiac cycle.

Using the R-R Interval

The fundamental principle is that if you know the duration of one heartbeat (the R-R interval), you can determine how many heartbeats occur in a minute.

The formula is:

Heart Rate (bpm) = 60 / RR Interval (seconds)

In this calculator, you simply input the measured RR interval in seconds. The calculator then divides 60 by this value to give you the heart rate in beats per minute.

The Role of ECG Paper Speed

ECG machines typically print the tracing on graph paper that moves at a standard speed. The most common speed is 25 mm/sec. While the R-R interval method doesn't directly use paper speed in its core calculation, understanding it is crucial for accurately measuring the R-R interval. Each small box on the ECG paper is usually 1 mm wide and represents 0.04 seconds (at 25 mm/sec), and each large box (5 small boxes) represents 0.20 seconds.

If you were to calculate the R-R interval manually by counting the small boxes, you would use the paper speed. For example, if the R-R interval spans 20 small boxes, and the paper speed is 25 mm/sec, the interval would be 20 boxes * 0.04 sec/box = 0.8 seconds.

Interpreting Heart Rate Values

  • Normal Heart Rate: For adults at rest, a normal heart rate is typically between 60 and 100 bpm.
  • Bradycardia: A heart rate below 60 bpm is considered bradycardia.
  • Tachycardia: A heart rate above 100 bpm is considered tachycardia.

It's important to note that these ranges can vary based on age, fitness level, and other physiological factors. An ECG technician or healthcare professional is best equipped to interpret the results within a clinical context.

Example Calculation

Let's say you measure the R-R interval on an ECG tracing and find it to be 0.8 seconds.

  • RR Interval = 0.8 seconds
  • Heart Rate = 60 / 0.8
  • Heart Rate = 75 bpm

Therefore, a heart rate of 75 beats per minute is calculated.

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