As a medical professional with expertise in cardiology, I can explain how heart rate can be determined from an ECG, which stands for electrocardiogram. An ECG is a test that records the electrical activity of the heart, providing a snapshot of the heart's rhythm and its overall function.

To determine the heart rate from an ECG, follow these steps:


1. Identify the QRS Complex: The QRS complex on the ECG represents the electrical activity that causes the ventricles to contract. It is the most prominent and recognizable feature of the ECG waveform.


2. Count the QRS Complexes: Count the number of QRS complexes in a 10-second interval. This is because a normal heart rate is between 60 and 100 beats per minute, which means there should be 3 to 5 QRS complexes in a second.


3. Calculate the Heart Rate: If there are three QRS complexes in 10 seconds, then there would be 18 QRS complexes in a minute (since 3 complexes x 6 equals 18). This would indicate a heart rate of 18 beats per minute. If there are five QRS complexes in 10 seconds, then there would be 30 QRS complexes in a minute (5 complexes x 6 equals 30), indicating a heart rate of 30 beats per minute.


4. Adjust for Irregular Rhythms: If the rhythm is irregular, you may need to measure the heart rate over a longer period or calculate the average beats per minute.


5. Use a Rhythm Strip: A rhythm strip is a continuous 10- or 15-second segment of an ECG. It is particularly useful for determining the heart rate in patients with irregular rhythms.


6. Calibration Marks: Keep in mind that the standard ECG paper has a calibration of 25 millimeters (mm) in height, which corresponds to 0.20 seconds in time. This can help you count the intervals between QRS complexes more accurately.

Remember, an ECG is a valuable tool for diagnosing various heart conditions, and determining heart rate is just one aspect of the comprehensive analysis that a healthcare professional performs.

read more >>

The pictorial explanation of this method is shown here. Another quick way to calculate the rate is based on the entire ECG being 10 seconds. By counting the number of QRS complexes and multiplying by six, the number per minute can be calculated �� because 10 seconds times six equals 60 seconds, or 1 minute.read more >>