ECG Interpretation Flashcards
Axis gives us the _________ of depolarization?
direction
The progressive depolarization of the __________ moves in a certain direction.
myocardium
AV node is the tail of the vector
Positive wave of depolarization is moving ______ a positive electrode, an ______ deflection.
toward
upward
What does a vector show?
the generalized direction of depolarization of the heart
Vector normally points down to between _ and ___ degrees.
0 and +90 degrees
When the left ventricle is thickened as in LVH then the vector ( wave of depolarization) will have a ______ deflection to the ____.
bigger
left
horizontal axis
Vectors swing ____ from damaged heart?
away
Mean QRS Vector?
AV node is the tail of the vector
To determine the axis:
use leads I and AVF
To determine the axis of the QRS vector use what leads?
I and AVF
QRS deflection of:
Lead 1: positive
AVF: positive
what is the resulting axis?
Normal
QRS deflection of:
Lead 1: positive
AVF: negative
what is the resulting axis?
LAD
left axis deviation
QRS deflection of:
Lead 1: negative
AVF: positive
what is the resulting axis?
RAD
Right axis deviation
QRS deflection of:
Lead 1: negative
AVF: negative
what is the resulting axis?
Extreme RAD or Extreme LAD
What can cause an extreme RAD or extreme LAD?
Extreme RAD: severe pulmonary HTN, severe RSHF, severe COPD
Emphysema Hyperkalemia Lead transposition Ventricular pacing Ventricular arrhythmia
What can cause a LAD?
HTN
Valvular disease
Past inferior MI left anterior fascicular block Ventricular pacing Emphysema Hyperkalemia WPW- right sided accessory pathway Tricuspid atresia Ostium primum atrial septum defect
What can cause a RAD?
Past MI on the left
RVH
Pulmonary HTN
PE
Normal in kids LVH COPD previous anterolateral MI PE ASD or VSD Dextrocardia Pectus excavatum WPW - left sided accessory pathway Left posterior fascicular block reversed arm leads
If LVH, what will you see in lead II?
Bifid P wave with > 40 ms between the two peaks
Total P wave duration > 110 ms
If LVH, what will you see in V1?
Biphasic P wave with terminal negative portion > 40 ms duration
Biphasic P wave with terminal negative portion > 1mm deep
one side has a stronger vector or wave of depolarization -
Right atrial enlargement (RAH) produces a peaked _ wave with amplitude: > ___ mm in the inferior leads (II, III, AVF) and > ___ mm in V1 and V2
P wave ( P pulmonale)
> 2.5 mm in inferior leads
> 1.5 mm in V1 and V2
V1 sits right above the right atrium so we get a big upward deflection in V1 with RAH
If RVH, V1 will show?
Large R wave
Small S wave
If LVH, V1 will show?
Deep S wave
If LVH, V5 will show?
Tall R wave
LVH, Sokolov-Lyon criteria?
S wave depth in V1 + tallest R wave height in V5-V6 > 35 mm.
What is ischemia (MI) and what is it characterized by on ECG
Reduced blood supply causing hypoxia
Characterized by inverted T waves
inverted T wave from an area in the heart that is not getting oxygen
If we are having an acute infarct ( happening now) what will we see on the ECG?
ST segment elevation:
>1mm in limb leads
> 2mm in 2 continguous precordial leads
What are reciprocal changes with MI injury?
St depression in other leads on the other side of the heart. because the vector is swinging
Ex.
2, 3, avf - inferior part of the heart ( inferior leads) - ST elevation
then…..
st depression in 1 and avl ( lateral leads) - this is the reciprocal change
With an Mi, what indicated necrosis on ECG?
Q wave indicates necrosis
Significant Q wave is 1 mm wide or 1/3 of the QRS amplitude
q waves are pathologic and indicated necrosis
Area of ECG changes correlates with area of ischemia: Anterior?
V1-V4
Area of ECG changes correlates with area of ischemia: Anteroseptal?
V1 and V2
Area of ECG changes correlates with area of ischemia: Anterolateral ?
V3 and V4
Area of ECG changes correlates with area of ischemia: Lateral?
I and AVL
Area of ECG changes correlates with area of ischemia: Inferior?
II, III, AVF
Area of ECG changes correlates with area of ischemia: Posterior?
Large R wave or ST depression in V1/V2
posterior MI are very hard to see on an EKG - cardiac enzymes for better determination
Area of ECG changes correlates with area of ischemia: Subendocardial?
Infarction that doesn’t extend through entire LV wall, flattened ST segments.
Brugada Syndrome is?
Familial condition caused by dysfunctional cardiac Na+ channels.
Brugada Syndrome findings on ECG
RBBB and ST elevation in leads V1-V3
ST segment convex to the top
ST segment downward straight
Pericarditis ECG findings?
Elevated the entire T wave from baseline
Produces elevated ST segments
it is the way the vector is going through the inflamed tissue
ST elevation in all of the leads
Pulmonary Embolism ECG findings?
S1Q3T3:
Large wide S in I
Large Q in III
Inverted T in III
Sinus Tachycardia is the most common finding on a EKG with a PE
COPD ECG finding?
Low voltage amplitude in all leads
RAD
barrel chested and a small heart ( small heart in a large chest )
“all the leads with kind of dampen”
Hyperkalemia ECG finding?
P wave flattens ( >9.0 mEq/L)
QRS widens (>7.5)
Peak T waves( >6.0)
electrolyte disturbances
elevated potassium levels - peaked T waves = because K is used in repolarization which is happening during a T wave
Hypokalemia ECG findings?
T wave flattened
U wave develops
At risk for Torsades
“Tiny bumps after a QRS complex“
lower and lower the K then the wider and wider the QRS
Hypocalcemia ECG findings?
QT interval lengthens (Torsades risk)
Hypercalcemia ECG findings?
QT interval shortens
Digitalis Effects on ECG finding?
Gradual downward curve of the ST segment
“Reverse check” or “Reverse tick” signs from digoxin effect
Pacemaker ECG findings?
Can see pacing “spike” on ECG
first spike is atria depolarization second is ventricularr
