Reading an ECG Flashcards
What is a normal heart rate?
60-100 bpm
When is a heart rate tachycardic?
>100bpm
When is a heart rate bradycardic?
<60bpm
How can a heart rate be calculated on a normal ECG?
Count the number of large squares present within one R-R interval. Divide 300 by this number to calculate heart rate. Example: - 4 large squares in an R-R interval - 300/4 = 75 beats per minute
What are the 2 types of irregular heart beats?
- Regularly irregular 2. Irregularly irregular
Describe regularly irregular
a recurrent pattern of irregularity
Describe irregularly irregular
completely disorganised
Photo of normal ECG
NEEDED
What represents the T wave?
Ventricular diastole
What represents the QRS complex?
Ventricular systole
What represents the P wave?
Atrial systole
What represents the dicrotic notch?
Closure of SL valves
What does a P wave with a chaotic baseline indicate?
fibrillation waves
What does a P wave with a sawtooth baseline indicate?
flutter waves
What does a flat line p wave indicate?
no atrial activity at all
What is a suggested diagnosis of absent P waves and irregular rhythm?
Atrial fibrillation
How long should the PR interval be?
120-200 ms (3-5 small squares).
What does the presence of a prolonged PR interval suggest?
Presence of AV delay (AV block)
Describe the PR interval during first-degree heart block (AV block)
a fixed prolonged PR interval (>200 ms)
What is complete heart block?
third-degree heart block occurs when there is no electrical communication between the atria and ventricles due to a complete failure of conduction
Describe an ECG of complete heart block
the presence of P waves and QRS complexes that have no association with each other, due to the atria and ventricles functioning independently
Where does first-degree AV block occur?
Between the SA node and AV node (within the atrium)
Where does third-degree (total) AV block occur?
Occurs at or after the AV node resulting in a complete blockade of distal conduction
What is a normal explanation for a shortened PR interval?
P wave is originating from somewhere closer to the AV node so the conduction takes less time (the SA node is not in a fixed place and some people’s atria are smaller than others)
What is a medical diagnosis for a shortened PR interval?
The atrial impulse is getting to the ventricle by a faster shortcut instead of conducting slowly across the atrial wall (accessory pathway)
