11. EKG part 3

Question 1

What does it mean to be balanced and bipolar on an ECG? Significance for QRS complex?

Answer 1

• Equal amplitudes up (+) & down (-)
• QRS complex is balanced and bipolar –> axis travels perpendicular to this lead

Question 2

What are the steps you take every time you encounter an EKG?

Answer 2

1. Determine if EKG is interpretable
2. Determine the rate
3. Check conduction system (pr & QRS intervals)
4. Determine the axis
5. Analyze the rhythm

Question 3

What is the normal appearance of the aV_R lead?

Answer 3

• P and QRS are negative

Question 4

Why is it normal for the aV_R lead to be negative?

Answer 4

It’s the only lead viewing the heart’s receding depolarization from above

Question 5

What is the most common cause of upright P and QRS waves lead aV_R?

Answer 5

Switched limb leads

Question 6

What 4 characteristics do we evaluate to confirm the cardiac rhythm?

Answer 6

• Rate/timing
• QRS width
• P wave characteristics
• Regularity of cardiac cycles

Question 7

What does a narrow QRS width denote? Wide?

Answer 7

• Narrow: supra-ventricular origin
• Wide: ventricular origin

Question 8

What are the criteria for a normal sinus rhythm?

Answer 8

• 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

Question 9

What is sinus arrhythmia?

Answer 9

Phasic variation of HR w/ inspiraiton (higher HR) and expiration (lower HR)

Question 10

What characterizes a high atrial premature beat?

Answer 10

Upright P wave suggests an ectopic focus high in the atria

Question 11

What characterizes a junctional premature beat?

Answer 11

• Inverted (retrograde) or absent P wave
• P waves too close to QRS (<0.12 secs)