lab quiz cardiac Flashcards
What is an ECG?
measure of the sum of all the charges outside the heart
what form of electrical activity is measured by an ECG?
heart rhythm and action potentials
why do lead 1, lead II, and lead iii all look different?
each different places from the heart and are recorded from different directions
why. is this important for medical personnel
gives precision to see where depolarizations occur
what does the P wave represent?
Atrial depolarization
what does the QRS represent
ventricle depolarization
T wave?
ventricle repolarization
why don’t we see a wave that represents the depolarization of the atria?
Because it happens at the same time ventricual waves depolarize
Flat line meaning
Tine between beats and no difference between electrical activity
heart rate equation
1500/number of small squares
60-100bpm
normal sinus rhythm
less than 60bpm
bradycardia
more than 100bpm
tachycardia
what causes the lab sound of the heartbeat?
AV valve closing
What causes the dub sound of the heartbeat?
semilunar valve closing
Why does the lab sound occur just after the peak of the R-wave?
Because the AV valve closes due to the heart contracting
Is the time delay between the R-wave and the lab sound always the same?
No, because blood pressure fluctuates.
why does the dub sound occur just after the peak of the T-wave?
b/c it closes when the heart relaxes the semilunar valve
