EKG Interpretation Unrein Lecture Flashcards
The Basics •Every time
–Rate –Rhythm –Axis –Hypertrophy –Infarction –Wave interval and segment abnormalities
Tracings •Waves -Summation Vectors
–P, Q, R, S, T, U
Tracings •Segments
–ST
Tracings •Intervals
- PR - QRS - QT
PR interval
less than 0.2 seconds (one big –five little boxes)
QRS interval
less than 0.12 seconds (three little boxes)
QT interval
0.44 seconds Bazett’s formula
Rate
–300, 150, 100, 75, 60, 50 –Six second strip -Multiply by 10 –Normal, Bradycardia, Tachycardia
QRS Sequence of Ventricular Depolarization
Depolarization starts at the ventricular septum (Q wave) and the endocardial surfaces. Average current flows from the base of the heart to the apex (R wave). At the end of depolarization, the current reverses, flows toward the outer walls of the ventricles near the base (S wave).
Atrial Rhythm simplified
•Up right P waves, narrow QRS
Junctional Rhythm simplified
•Absent or inverted P waves, narrow QRS
Ventricular Rhythm simplified
•No p waves •Wide QRS complexes
Repetitive Sequence Rhythm simplified
•Bigeminal, Trigeminal, Quadrigeminal –A series-pattern of ectopic depolarizations, either atrial or ventricular in origin
Physiology that affects Rhythm
–Sympathetic •adrenergic –Parasympathetic •Cholinergic –Depolarization/repolarization •Automaticity –Escape beats »Refractory periods –Premature »Irritable focus »Reentry –Injury/scaring
Supraventricular Rhythms
–Sinus/Atrial –Junctional –Wolf-Parkinson-White (WPW)
–Sinus/Atrial Rhythm Overview
•Sinus arrhythmia •Wandering pacemaker, multifocal atrial tachycardia (MAT) •Paroxysmal atrial tachycardia (PAT) •Artial flutter –Singular atrial focus–reentry mechanism •Artial fib –Lack of any organized atrial activity
Junctional Rhythm Overview
•Paroxysmal junctional tachycardia (PJT) •AV nodal reentry
Wolf-Parkinson-White (WPW) Rhythm overview
•Accessory conduction pathway (bundle of Kent) •Delta waves •Often has the appearance of an IWMI, this determination must be interpreted carefully •Shortened PR interval
Wandering Pacemaker
Irregular Rhythm P’ wave shape varies atrial rate less than 100 irregular ventricular rhythm
Atrial Bigeminy
normal sinus beat followed by an abnormal beat
atrial flutter
sawtooth
atrial fibrillation
no p waves, qrs coming in at no pattern
Junctional Rhythm notes
no p waves, so not atrial origin
if qrs is truly widended and not from a supraventricular origin, the upper limit is 3 boxes
inverted p waves, conduction is retrograde from junctino up to atria
Wolf-Parkinson-White (WPW) notes
p wave runs into qrs to make delta wave
First Degree AV Blocks
•Prolonged PR interval -> 0.2 seconds
Second Degree AV block overview
Variable penetration of AV conductions –lone P waves without a QRS conduction following
Type I second degree AV block
(conduction abnormality in the AV node and heavy parasympathetic influence)
–Wenckebach
–Progressively prolonged PR intervals with a subsequent dropped beat and lone P wave –usually a fixed ratio/pattern
–Vagal maneuvers
type II second degree AV block
–Mobitz
–Failure of AV conduction in a fixed ratio/pattern, the PR interval is not gradually increasing in length
–Widened QRS
multiple p waves to each qrs?
Third Degree AV block
–Complete Atrial and Ventricular dissociation –both are being independently paced
wenckeback is a…
Regularly Irregular pattern
Ventricular Dysrhytmias
Wide QRS complex tachycardia
greater than .12
usually less than 40
Ventricular tachycardia
Torsades De Pointes
Vetricullar Fibrillation
Ventricular Dysrhythmias
Wide QRS complex tachycardia
–Supraventricular vs. ventricular
Ventricular Dysrhythmias
Ventricular Tachycardia
–Irritable focus of a ventricular origin –usually reentry mechanism
Ventricular Dysrhythmias
Torsades de Pointes
twisted ribbon
Ventricular Dysrhythmias
Ventricular fibrillation
–Multiple irritable automatic foci depolarizing
Prolonged QT syndrome leads to?
Torsades de pointes
Prlonged QT syndrome can be caused by hypo-
magnesemia
Right Bundle Branch Block
»Left bundle conducts first
»Best viewed inV1 V2
Left Bundle Branch Block
»Right bundle conducts first
»Best viewed in V5 V6
Axis
Vector direction and mass summation
–Limb leads –frontal plane (Determine axis)
–Chest Leads –horizontal plane (Determine rotation)
–0-90 degrees is normal (actually -30 to 110)
–Isoelectric point
•Right angle from the axis plane
Atrial Hypertrophy
Lead V1
–Used to assess atrial enlargement
–Positioned over the atria right side of the chest
•Biphasic P wave – the predominate vector deflection determines the hypertrophy
–positive right atrial hypertrophy
–negative left atrial hypertrophy
Atrial Hypertrophy
Leads II, III, aVF (heart lays on its side)
–amplitude is increased to greater than 2.5 mm in leads II, III, aVF is also indicative of right atrial hypertrophy (also referred to as p-pulmonale)
Ventricular Hypertrophy Overview
•Can be determined electrically with caution in the presence of a Bundle Branch Block
•Electrical size
–Chamber size increase – dilation
–Increased muscle mass
Ventricular Hypetrophy
V1
–positioned over the atria right side of the chest
–Used to assess atrial enlargement
•Biphasic P wave
–Used to assess right ventricular hypertrophy - abnormally large R wave
–Used to assess left ventricular hypertrophy - abnormally large S wave
Ventricular Hypertrophy
V5
–Used to assess left ventricular hypertrophy - abnormally large R wave
Left ventricular hypertrophy
–Millimeters on EKG of S wave in V1 plus the R wave in V5 > 35mm
–Inverted/asymmetric T waves (repolarization abnormality)
–Strain pattern depressed and humped ST segment
Infarction - Ischemia
–Symmetrically inverted T waves
–ST segment depression subendocardial infarction, angina, stress tests
Infaction - injury
–Acute
•ST segment elevation transmural infarction
Infarction - Necrosis
–Q waves
•Old injury
Myocardial Infarction - inferior
II,III,AVF
Myocardial Infarction - anterior
V1-4
Myocardial Infarction - lateral
I,AVL,V5-6
Myocardial Infarction - Posterior
V1,V2 - tall R wave and ST depression
Myocardial Infarction - LBBB
EKG is invalid diagnostic tool for Acute MI
Firemans hat sign shows what?
MI
Posterior-lateral Wall MI Artery?
Circumflex Artery (with anterior reciprocal changes)
Hyperkalemia
- Flattened/widened P waves
- Widened ORS complexes
- Peaked T waves
Hypokalemia
- Flattened T waves
- Prominent U waves
Hypercalcemia
- Shortened QT interval
- Widened T wave
Hypocalcemia
- Prolonged QT interval
- Flattened T waves
Hypothermia
•Severe sinus Bradycardia
•Prolonged PR interval
•Widened QRS complex
•Prolonged QT interval
•Osborn wave
–Extra deflection at the end of the QRS complex
Pericarditis
- ST segment elevation that is flattened with T wave elevated off the baseline
- Usually present in all leads
- Convincing evidence of PR segment depression
Paced Rhythm
- Sharp depolarizations - spikes
- Unable to interpret anything beyond that it is a paced rhythm
- Can be atrial, ventricular or AV sequential pacers
Atrial Flutter
Atrial Bigeminy
Atrial fibrillation
Rhythm
Junctional
Rhythm
Junctional
Wolf-Parkinson-White (WPW)
Wolf-Parkinson-White (WPW)
First degree AV block
Wenckebach
Wenckebach
Second Degree AV Block Mobitz type II
Second Degree AV Block Mobitz type II
Third Degree AV Block
Ventricular Bigeminy
Ventricular Tachycardia
Ventricular Tachycardia
Torsades de Pointes
Prolonged QT Syndrome
Prolonged QT Syndrome (Hypomagnesemia)
Vetricular Fibrillation
RBBB
RBBB
LBBB
Axis
+30
Axis
- 90
Axis
- 60
Axis
0
Axis
+100
Left Atrial Hypertrophy
Left Atrial Hypertrophy
Right Atrial Hypertrophy
Left Ventricular Hypertrophy
Left Ventricular Hypertrophy - with Strain Pattern
Left Ventricular Hypertrophy - with Strain Pattern
Anterior Ischemia
Inferior Wall MI
Inferior Wall MI
Anterolateral Wall MI
Posterior MI
Posterior-lateral Wall MI - ircumflex Artery (with anterior reciprocal changes)
Hyperkalemia
hypercalcemia
Hypocalcemia
Hypothermia
Hypothermia
Hypothermia
Hypothermia
Hypothermia
Hypothermia
Pericarditis
Reciprocal changes in V1, I and aVL
Pericardial effusion?
Paced Rhythm
Paced Rhythm
Paced Rhythm
Dextrocardia
