What is a mm on ECG?
The ECG paper speed is ordinarily 25 mm/sec. As a result, each 1 mm (small) horizontal box corresponds to 0.04 second (40 ms), with heavier lines forming larger boxes that include five small boxes and hence represent 0.20 sec (200 ms) intervals.
How do you read ECG rate?
Rate = Number of R waves X 6. The number of complexes (count R waves) on the rhythm strip gives the average rate over a ten-second period. This is multiplied by 6 (10 seconds x 6 = 1 minute) to give the average Beats per minute (bpm)
How is ECG irregular rate calculated?
If the heart rate is irregular, count the number of QRS complexes on the ECG and multiply by 6 to obtain the average heart rate in bpm (the ECG displays a period of 10 seconds; thus, 6 × 10 seconds = 60 seconds [1 minute]).
What does sinus tachycardia look like on ECG?
Sinus tachycardia is recognized on an ECG with a normal upright P wave in lead II preceding every QRS complex. This indicates that the pacemaker is coming from the sinus node and not elsewhere in the atria, with an atrial rate of greater than 100 beats per minute.
What are the normal measurements for an ECG?
The Normal ECG. Standard Calibration. A standard ECG is recorded at 25mm/sec and with a frequency cut off of no lower than 150Hz in adults, and 250Hz in children.
What is a small box on an EKG?
A small ECG box measures 1 mm, while a big one has a length of 5 mm. They represent different duration times depending on the speed of paper set in an ECG machine. When the paper speed is set at 25 mm/s, which is a value used in most cases, with each small box on X-axis, 0.04 sec of time passes.
How many seconds are in an EKG box?
Each ECG is divided by large boxes and small boxes to help measure times and distances. Each large box represents 0.20 seconds, and there are five small boxes in each large box, thus each small box is equivalent to 0.04 seconds.
What is an EKG rate?
Normal heart rhythm. Overview. An electrocardiogram (ECG) test measures the electrical activity of the heart. A normal resting heart rate is 60 to 100 beats per minute.