EKG Flashcards
what leads do you look at for BBB
V1 (V2) and V6 (V5)
causes of right BBB
- normal
- rate related (if HR is high especially in paroxysmal)
- CAD
- Ventricular hypertrophy
- aberrant ventricular conduction
- Congenitial heart disease
- Acute dilation of the RV
- MI
- conduction system disease
not as ominous as left BBB
Causes of Left BBB
more ominous than right BBB - MI or ischemia - congestive heart failure - quinidine - occasionally seen in normal individuals - HTN -Conduction system disease - cardiomyopathy - Severe AS if patient has CP and new LBBB needs to go to cath immediately because it is difficult to see ST changes with LBBB
Causes of left ventricular enlargement
- chronic HTN
- cardiomyopathy/CHF
- chronic mitral regurgitation
- chronic aortic stenosis/ regurgitation
- VSD with pulmonary HTN
- obesity
- cocaine
- anabolic steriods
- extreme athletic conditioning
Calculating HR with the box method
1 box- 300 2 boxes- 150 3 boxes- 100 4 boxes- 75 5 boxes- 60 6 boxes 50
P wave
small rounded upright wave ( atrial depolarization)
Q wave
first negative deflection after a P wave
R wave
first positive deflection after a p wave
s wave
first negative deflection after an r wave
ST segment elevation means
injury
ST segment depression means
ischemia
Lead 1 has a positive electrode…
left arm– perpendicular, a little up a little down
lead II has a positive electrode
left foot, positive QRS, electrical forces towards the positive
Lead III has a positive electrode
left foot upward positive QRS
Lead aVR has a positive electrode
right arm, QRS negative deflection, away from the positive electrode… P and T wave inverted is normal
Lead aVL has a positive electrode
on the left arm… perpendicular biphasic QRS alittle up and a little down
Lead aVF has a positive electrode
on the left foot, positive QRS
Inferior leads
II, III, aVF ( all have a positive electrode on the left foot), RCA (in the majority of people)
Lateral leads (high lateral)
I, aVL (positive electrode is on the left arm) left circumflex in the majority of people
Septal leads
V1 V2, LAD
Anterior Leads
V3, V4, LAD
Low lateral leads
V5, V6, left circumflex in the majority of people
What leads do you look at for axis determination
Lead I and aVF
Normal axis
Lead I positive avF positive
Left axis deviation
Lead 1 positive, aVF negative
indeterminate axis
lead I negative and aVF negative
Right axis deviation
Lead I negative and aVF positive
Causes of Left axis deviation
- Normal
- LBBB
- Left anterior hemiblock
- inferior wall MI
- Left ventricular hypertrophy
- cardiomyopathies
- congenitial heart disease
- severe pulmonary disease
- aberrant ventricular
conduction
Causes of right axis deviation
- normal
- right BBB
- Left posterior hemiblock
- right ventricular hypertrophy
- anterolateral MI
- Severe pulmonary disease
- aberrant ventricular conduction
- reversal of right and left arm leads
posterior wall leads
V1 V2 mirror image changes, posterior descending artery (PDA)
