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Flashcards in EKG fundamentals Deck (17)
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How long should the PR interval take?

0.12-0.2 sec or 3-5 small squares (this represents the time that the conduction is 'stuck' at the AV node to allow ventricular filling to complete)

too long= 1st degree heart block


How long should the QRS complex take?

less than 0.12 sec or 3 small squares


How long should the QT interval (beginning of Q to end of T wave) take?

varies inversely with heart rate (faster HR = shorter QT)

at 60 bpm, the QT should be between 0.35-0.46 seconds (9-12 squares)


What lead is being read on a rhythm strip?

lead II


How to read a rhythm strip.

1) divide 300 by the number of large squares between 2 adjacent R waves

2) or if the rhythm appears irregular, look at the number of R waves that occur within 30 large squares and multiply by 10


What could cause a prolonged QRS complex?

- impulse blocked after AV node
- pulse originates in the ventricles (ventricular tachycardia)


How would atrial fibrillation look on an ECG?

-no P wave
-irregular QRS

AV node is overwhelmed and only some impulse gets through


What would super ventricular tachycardia look like on an ECG?

-absence of P wave
-Very close QRS complexes


What would an atrial flutter look like?

-sawtooth shape of P wave

the SA is firing way too fast (300 bpm) and the AV only lets through half (150bpm), a third (100bpm), or 1/4th (75bpm)


What are the two types of 2nd degree heart block?

Mobitz 1


What does Moritz 1 look like on an ECG?

continually increasing PR interval before dropping a PR interval completely and resetting


What does Moritz 2 look like on an ECG?

dropped QRS with an otherwise regular PR interval- can be random or patterned


What does a 3rd degree bock look like?

- very serious
- AV node is defective and eventually the ventricles will begin to fire on their own as a safety net


What is the cardiac axis?

average direction of flow of electricity in the heart


What is the normal cardiac axis?

+90 to -30


What is left axis deviation?

-90 to -30


What is right axis deviation?

+180 to +90