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Asked by: Guerau Azhnikoff
medical health heart and cardiovascular diseasesHow do you measure QRS duration?
Correspondingly, what is the normal QRS duration?
The normal duration (interval) of the QRS complex is between 0.08 and 0.10 seconds — that is, 80 and 100 milliseconds. When the duration is between 0.10 and 0.12 seconds, it is intermediate or slightly prolonged. A QRS duration of greater than 0.12 seconds is considered abnormal.
Also question is, how is an ECG measured?
ECG paper is a grid where time is measured along the horizontal axis.
- Each small square is 1 mm in length and represents 0.04 seconds.
- Each larger square is 5 mm in length and represents 0.2 seconds.
Normal range 120 – 200 ms (3 – 5 small squares on ECG paper). Normal range up to 120 ms (3 small squares on ECG paper). QT interval (measured from first deflection of QRS complex to end of T wave at isoelectric line). Normal range up to 440 ms (though varies with heart rate and may be slightly longer in females)