EKG Characteristics Flashcards
P-wave
atrial depolarization, causing atrial contraction
QRS Complex
ventricular depolarization, causing ventricular contraction
ST segment and T-wave
ventricular re-polarization
U wave
will probably result from slow or delayed re-polarization of Purkinje fibers
View of Heart: II
inferior
View of Heart: III
inferior
View of Heart: aVF
inferior
View of Heart: I
lateral
View of Heart: aVL
lateral
View of Heart: V5
lateral
View of Heart: V6
lateral
View of Heart: V3
anterior
View of Heart: V4
anterior
View of Heart: V1
septal
View of Heart: V2
septal
tall P-waves in II, III, and aVF
indicates right atrial overload
seen in Pulmonary Valve Stenosis
right axis deviation (negative QRS in V1) and rSR’ in V1
Atrial Septal Defect
RVH and right axis deviation; right bundle branch block pattern in patients who have had surgical repair; beware of arrythmias if QRS width is greater than 180 msec
Tetralogy of Fallot
1 mm horizontal or downsloping ST-depression that occurs, then reverses after ischemia disappears; occurs during stress test then goes away
Stable Angina
1 mm elevation of ST-segment; new Q waves; may see T-wave inversion
STEMI
STEMI Location: II, III, aVF
inferior wall
STEMI Location: I, aVL, V4-V6
lateral wall
STEMI Location: V1-V3
anteroseptal
STEMI Location: V1-V6
anterolateral
Right ventricular
RV4, RV5
Posterior Wall
R/S ratio greater than 1 in V1 and V2 adn T-wave changes in V1, V8, and V9
an increase in duration or a QRS complex is sign of
delayed conduction through the ventricle
a large q-wave may indicate a ______, and a diagnostically significant Q wave is usually ______.
recent or old infarction
0.04 seconds in duration and 1/3 the size of the QRS complex
How does Ventricular Hypertrophy effect the QRS?
amplitude greater than 35 mm
a QRS amplitude less than 5 mm indicates?
CAD, emphysema, marked obesity, generalized edema, or pericardial effusion
ST-segment depression
ischemia or NSTEMI (20-25%)
ST-segment elevation
injury/STEMI (unless in Prinzmetal Angina)
Right Axis Deviation
- QRS in I; + in aVF
Left Axis Deviation
+ QRS in I; - in aVF
Right Chest Leads
V1 and V2
Left Chest Leads
V5 and V6
Right BBB
widened QRS
R,R’ in V1 and V2
Positive QRS in V1
Left BBB
widened QRS
R,R’ in V5 and V6
negative QRS in V1
Atrial Hypertophy
look in V1
P-wave is diphasic – both positive and negative
Initial portion is larger or taller, right atrial hypertrophy.
Terminal portion is larger, left atrial hypertrophy.
• Regular tachycardia
• QRS complex usually narrow unless there is aberrant conduction or a pre-existing bundle branch block
• ST-segment depression may be seen with or without the presence of CAD
• P waves may be:
o Buried in the QRS complex
o Visible after the QRS complex (this example)
o (Rarely) visible before the QRS complex
o atria and ventricles are contracting at about the same time
AVNRT
- Short PR interval (<120 ms)
- Delta wave: “slurring” of initial portion of QRS (ventricular pre-excitation)
- QRS prolonged > 110 ms
- S-T and T waves can be inverted (opposite to the major portion of the QRS)
AVRT
irregularly irregular rate and rhythm
absence of P-waves
irregular ventricular response
rate can be slow or fast
Atrial Fibrillation
back-to-back identical flutter waves described as having a “sawtooth” appearance; especially in leads II, III, and aVF
not a QRS for every P-wave
Atrial Flutter
Varying P wave morphology and irregular P-P intervals
rate exceeds 100
Multifocal Atrial Tachycardia (MAT)
wide QRS complexes that vary from other QRS complexes in the same lead and are not preceded by a P-wave
Premature Ventricular Contractions
3 or more consecutive premature ventricular beats (wide QRS complexes)
rapid rate: >120, but typically 160-240
Ventricular Tachycardia
wide complex rhythm
rate of 60-120 bpm
Accelerated Idioventricular Rhythm
QT intervals greater than 440 msec
Long QT Syndrome
Regular, generally narrow, QRS complexes without p-waves preceding them.
May sometimes see retrograde p-waves after the QRS in the ST segment or t-wave
Junctional Rhythms
fixed, prolonged PR interval
every P has a QRS
normal QRS width
First Degree AV Block
Progressive lengthening of PR interval until a QRS is dropped
P wave falls in refractory period of ventricles and fails to conduct impulse to ventricles
Regular P-P interval
Irregular R-R interval
QRS width is normal
Second Degree AV Block Mobitz Type I
Fixed normal PR interval with intermittent dropped QRS
Regular P-P interval
Irregular R-R interval
There is a P for every QRS but not a QRS for every P
QRS may be widened if the block occurs below the bundle of His
Second Degree AV Block Mobitz Type II
No relationship between P waves and QRS complexes: PR interval varies
Atria and Ventricles beat independently
Regular P-P and R-R interval
Third Degree AV Block
alternating bradycardia and tachycardia
Tachy-Brady Syndrome
Narrow Complex Tachycardias with Regular Atrial Rhythm
Sinus tachycardia
Atrial tachycardia
Atrial flutter
Narrow Complex Tachycardias with Irregular Atrial Rhythm
Atrial fibrillation
Atrial flutter with variable block
Multifocal atrial tachycardia
Narrow Complex Tachycardias with Regular Atrioventricular Rhythm
AV nodal re-entry tachycardia (AVNRT): Stuck in a roundabout
Atrioventricular re-entry tachycardia (AVRT) (bypass tract): there is a detour back to the atria, stuck driving around the main road-detour circle every time
Junctional tachycardia
Wide complex tachycardias; Regular
Ventricular tachycardia
SVT with aberrant conduction
AVRT with antidromic conduction
Wide complex tachycardias: Irregular
Ventricular fibrillation
Polymorphic ventricular tachycardia
Torsades de Pointes
AVRT/WPW with atrial fibrillation
Bradycardias: P wave present
P always followed by QRS
Sinus bradycardia
First degree AV block
Sinus pause/arrest
Bradycardias: P wave present
P not always followed by QRS
Second degree AV block: Mobitz I (Wenckebach), Mobitz II, Fixed ratio, eg 2:1, 3:1
Third degree AV block
Bradycardias: P wave absent
Narrow Complex: Junctional Escape Rhythm
Wide Complex: Ventricular Escape Rhythm
