EKG III Lecture Powerpoint

Question 1

Per 5 squares of an EKG horizontally, we measure ___mm and ___sec

Answer 1

5, .2

Question 2

Atrial foci, junctional foci, and ventricular foci

Answer 2

Back up pacemakers that can take over in the case of failure of SA node at approx 60-80 bpm, 40-60 bpm, and 20-40bpm respectively

Question 3

Quick estimate determination of HR from EKG

Answer 3

• Find an R wave that starts on a heavy dark line

- Start counting at next black line 300 to 150 to 100 to 75 to 60 to 50 to 43 to 38 until you hit the next R wave

Question 4

6 second strip method of HR from EKG

Answer 4

• Take 2 of the 3 second intervals marked at the top of the ekg page to get a 6 second interval
• find number of cycles within a 6 sec strip x 10 = cycles per min

Question 5

“Sinus” definition (as in sinus tachy or bradycardia)

Answer 5

Occurs when every p wave has a corresponding QRS complex and QRS follows each corresponding P wave

Question 6

Things that can alter the axis of the heart (3) as well as what is the normal axis range of the heart

Answer 6

• obesity
• hypertrophy
• infarction

Normal range is -30 degrees to +90 degrees (remember we are going clockwise from 3 o’clock for positive values to 180 and counterclockwise from 3 o’clock for negative values to -179

Question 7

Axis determination quick method

Answer 7

If the QRS is positive in lead I and positive in AVF you have a normal axis

Question 8

QRS up in I and down in AVF means…
QRS down in I and up in AVF means…
QRS down in both I and AVF means…

Answer 8

…left axis deviation
…right axis deviation
…extreme right axis deviation

Question 9

If a wave of depolarizastion or repolarization travels perpendicular to an electrode axis resulting in…

Answer 9

….electrode axis that results in QRS biphasic deflection of equal positive and negative voltages (no net deflection)

Question 10

Causes of right axis deviation (3)

Answer 10

• COPD
• Pulmonary hypertension
• anteriolateral MI

Question 11

Causes of left axis deviation (4)

Answer 11

• mechanical shifts
• inferior wall MI
• LVH
• Left bundle branch block