MEDICAL
ARTERIES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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0.25mm/second
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0.025mm/second
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2.5mm/second
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25mm/second
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Detailed explanation-1: -At standard paper speed of 25mm/sec, the rhythm strip comprises of: 250 SMALL squares = 50 LARGE squares = 10 seconds.
Detailed explanation-2: -Normal ECG. A normal ECG is illustrated above. Note that the heart is beating in a regular sinus rhythm between 60-100 beats per minute (specifically 82 bpm). All the important intervals on this recording are within normal ranges.
Detailed explanation-3: -Measurements. Because ECG paper moves at a standardized 25mm/sec, the vertical lines can be used to measure time. There is a 0.20 sec between 2 of the large lines. Therefore, if you count the number of heart beats (QRS complexes) in between 30 large boxes (6 seconds) and multiply by 10, you have beats per minute.
Detailed explanation-4: -The ECG is recorded at a speed of 25 mm/sec (5 large squares/sec), and the voltages are calibrated so that 1 mV = 10 mm (2 large squares) in the vertical axis. Therefore, each small 1-mm square represents 0.04 sec (40 msec) in time and 0.10 mV in voltage.