EKG III Lecture Powerpoint Flashcards
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Per 5 squares of an EKG horizontally, we measure ___mm and ___sec
5, .2
Atrial foci, junctional foci, and ventricular foci
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
Quick estimate determination of HR from EKG
- 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
6 second strip method of HR from EKG
- 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
“Sinus” definition (as in sinus tachy or bradycardia)
Occurs when every p wave has a corresponding QRS complex and QRS follows each corresponding P wave
Things that can alter the axis of the heart (3) as well as what is the normal axis range of the heart
- 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
Axis determination quick method
If the QRS is positive in lead I and positive in AVF you have a normal axis
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…
…left axis deviation
…right axis deviation
…extreme right axis deviation
If a wave of depolarizastion or repolarization travels perpendicular to an electrode axis resulting in…
….electrode axis that results in QRS biphasic deflection of equal positive and negative voltages (no net deflection)
Causes of right axis deviation (3)
- COPD
- Pulmonary hypertension
- anteriolateral MI
Causes of left axis deviation (4)
- mechanical shifts
- inferior wall MI
- LVH
- Left bundle branch block
