What does it mean to be balanced and bipolar on an ECG? Significance for QRS complex?
- Equal amplitudes up (+) & down (-)
- QRS complex is balanced and bipolar --> axis travels perpendicular to this lead
What are the steps you take every time you encounter an EKG?
- Determine if EKG is interpretable
- Determine the rate
- Check conduction system (pr & QRS intervals)
- Determine the axis
- Analyze the rhythm
What is the normal appearance of the aVR lead?
- P and QRS are negative
Why is it normal for the aVR lead to be negative?
It's the only lead viewing the heart's receding depolarization from above
What is the most common cause of upright P and QRS waves lead aVR?
Switched limb leads
What 4 characteristics do we evaluate to confirm the cardiac rhythm?
- QRS width
- P wave characteristics
- Regularity of cardiac cycles
What does a narrow QRS width denote? Wide?
- Narrow: supra-ventricular origin
- Wide: ventricular origin
What are the criteria for a normal sinus rhythm?
- HR = 60-100 bpm
- QRS width is narrow (<0.10 ms)
- P wave is positive in lead II
- PR duration 0.12 - 0.20 ms
- 1:1 P:QRS ratio
- Regularly spaced QRS's
What is sinus arrhythmia?
Phasic variation of HR w/ inspiraiton (higher HR) and expiration (lower HR)
What characterizes a high atrial premature beat?
Upright P wave suggests an ectopic focus high in the atria
What characterizes a junctional premature beat?