Axis & Chamber Enlargement Flashcards
Predominant direction is positive in Leads I and aVF, this indicates a ______ axis
normal
Lead 1: Positive
aVF: Negative
LAD
Range between 0 and -90 degrees…
LAD
Lead 1: negative
aVF: Positive
RAD
Lead 1: negative
aVF: negative
indeterminate/extreme axis
range between 90 and 180
RAD
Range between -90 and 180
indeterminate
aVF degrees…
+ 90
Lead I degrees
0
The axis points in the direction of the lead with the ________ QRS complex in the frontal plane
tallest QRS complex
The axis is ________ to a lead with an equiphasic QRS complex
perpendicular
Positive deflection lead I = aVF
+45 degrees (halfway between 90 and 0)
Positive deflection lead I > avF
axis between 0 and 45 (closer to Lead I)
positive deflection lead I < aVF
axis between 45 and 90 (closer to aVF
R wave in aVL > R wave in Lead I…
Strong LAD w. LAHB
R wave in lead III > R wave in aVF
Strong RAD w. LPHB
The below are causes of…
• Q waves of inferior myocardial infarction
• Chronic coronary artery disease
• Diffuse myocardial disease, such as
cardiomyopathy, amyloidosis, myocarditis, etc.
• Some cases of hyperkalemia
• Wolff-Parkinson-White syndrome with a rightsided
accessory pathway
• Left ventricular hypertrophy
LAD
The below are causes of…
• Normal finding in children and tall thin adults • Right ventricular hypertrophy • Chronic lung disease even without pulmonary hypertension • Anterolateral myocardial infarction • Left posterior hemiblock • Pulmonary embolus • Dextrocardia
RAD
Who might have a vertical heart, with mean QRS axis toward 90 degrees?
tall, thin individuals
Who may have a more horizontal heart, with the mean QRS shifting more leftward?
obese, pregnant
Atrial enlargement is assessed in which leads?
II, V1
P wave amplitude > 2.5 mm (2.5 boxes)
RAE, P Pulmonale
P wave duration > 0.10s (2.5 boxes)
LAE, P Mitrale
P wave amplitude > 2.5 mm (2.5 boxes) and duration > 0.10s (2.5 boxes)
Biatrial enlargement
In lead V1, how is RAE identified?
upward deflection > downward deflection
V1 P waves are usually…
biphasic
The below are common conditions with…
Pulmonic stenosis
Tricuspid stenosis
Tricuspid regurgitation
RAE
In lead V1/V2, how is LAE identified?
negative deflection > 0.04s and > 1mm deep
(1 box wide and deep)
(prolonged and deep, scoop like)
In LAE, what should you see in leads I, II, and V4 - V6?
notched, broad P wave
The below conditions present with…
Mitral stenosis
Mitral regurgitation
LAE
The below are common causes of what?
- Hypertension
- Valvular heart disease
LVH
LVH can be diagnosed if the sum of the deepest ____ in ____/______ + tallest _____ in ___/_____ are > _____mm
deepest S in V1 or V2 + tallest R in V5 or V6 > 35mm
LVH can be diagnosed if the R wave in ____ is > ____
R wave in aVL is > 11mm
LVH can be diagnosed if the R wave in _____ + the S wave in ______ are > _____
R in Lead I + S in Lead III > 25mm
RAD can indicate what chamber abnormality?
RVH
LAD can indicate what chamber abnormality?
LVH
R wave > S wave in V1 indicates…
RVH
S wave > R wave in V6 indicates…
RVH
Downward progressing R waves from V1-V5 indicates…
RVH
very large R waves in lateral leads (V4, V5, V6) can indicate
LVH
