Reading an ECG Flashcards
What should you determine first on an ECG?
Heart rhythm
What suggests a regular heart rhythm?
All R-R intervals are the same length
What suggests a regularly irregular rhythm?
Recurrent pattern of irregularity (i.e. R-R length = 5, 12, 5, 12 etc.)
What suggests an irregularly irregular rhythm?
No pattern of irregularity
After heart rhythm, heart rate is determined. True/false?
True
In a regular rhythm, what equation is used to determine rate?
Rate = 300 / no. of large squares in R-R interval
In an irregular rhythm, what equation is used to determine rate?
Rate = 10 x no. of QRS complexes in 30 large squares
What lead is most positively deflected in a normal cardiac axis?
Lead II
In right axis deviation, lead I has the most positive deflection and lead III is negative. True/false?
False
Other way around
What are the lead deflections in left axis deviation?
Lead I most positive deflection
Leads II and III are negative
P waves should be present and follow each QRS complex. True/false?
False
Should be before each QRS complex
How long should the P-R interval be?
3-5 small squares (0.12-0.2s)
The width of a QRS complex should always be less than 3 small squares (<0.12s). True/false?
True
The ST segment should be what between the end of the S wave and start of the T wave?
Isoelectric (neither elevated or depressed)
How tall should T waves be in limb leads and chest leads?
No bigger than 5mm in limb leads
No bigger than 10mm in chest leads
