What is Step 1
What can rhythm be?
- regular (R-R intervals within 0.04 seconds)
- regularly irregular (a pattern exists)
- irregularly irregular (no pattern, chaotic)
How do you determine rhythm?
Use piece of paper with lines
What should be considered if rhythm is regularly irregular?
Respiratory Sinus Arrythmia
Explain Respiratory Sinus Arrythmia
Changes in venous return and vagal tone: during inspiratory venous return increases causing vagal tone to decrease (increases HR). During expiration a reduction in venous return increases vagal tone (reduces HR).
By how much does RSA change P-P interval
Determine the rate
How many large squares are in 1 minute?
What speed does the ECG paper move at?
How do you calculate HR in a regular rhythm?
300/no. of large squares in R-R interval
How do you calculate HR in a irregular rhythm?
count no. of QRS complex in 30 large squares then x 10
Evaluate the P wave
- Are P-waves present?
- Do they all have normal configurations?
- Are they all similar shape and size?
- Is there one P-wave for every QRS?
Determine duration of PR interval
- is it between 0.12 - 0.2 seconds
- is the PR interval constant?
Determine height and duration of QRS?
- is the duration normal? 0.05 - 0.1 seconds
- does a QRS complex appear after every P wave
- Are all QRS complexes the same size and shape?
- Are the QRS R/S waves too deep/high? 25 mm individually or 35 mm combined?
Is ST segment isoelectric
- 1.0 mm elevation
- 0.5 mm depression
at 80 ms past j-point (2 squares)
Is the ST segement upsloping/downsloping or horizontal?
Evaluation the T wave
- Are T waves present
- Do they have a normal shape
- Do the have a normal amplitude (10mm precordial leads)
- Do they all have the same amplitude?
- Do the T waves have the same deflection as QRS complex?
Determine the QT interval
- 0.35 - 0.44 seconds corrected
Evaluate any other components
- origin of rhythm (SA node/AV node/ventricles)
- rate (bradycardia/tachycardia)
- rhythm abnormalities