EKG’s By: Robby Zehrung

Leads  In a 3-lead View there are two types of Leads:  Bipolar  Lead I: Right Arm to Left Arm  Lead II: Right Arm to Left Foot  Lead III: Left Arm to Left Foot  Unipolar  AVF: Left Foot to Heart  AVL: Left Arm to Heart  AVR: Right Arm to Heart

Deflection

Waves and Normal Values Wave/SegmentLengthHeight P-WaveLess than 0.12Less than 2.5 mm PR-Interval0.12 to 0.20N/A QRS Complex0.04 to 0.12Variable ST SegmentN/AIsoelectric QT-SegmentLess than 0.44 secN/A

Regularity and Rate  A rhythm can be Regular or Irregular  Regular- There is the same number of boxes between each R to R interval and the same number of boxes between each P to P interval.  Irregular- The number of boxes between the R to R and P to P intervals varies.  To determine the rate you can use one of three methods:  Rule of 300- Count the number of Big boxes between the R to R interval and divide it into 300)  Rule of 1500 (Count the number of small boxes between the R to R intervals and divide it into 1500)  6 Second Rule- Count the number of boxes on a 6 second strip and multiple by 10. (This is best when the regularity is irregular.)

Sinus Rhythms  Sinus Rhythm  Sinus Tachycardia  Sinus Bradycardia  Sinus Arrhythmia  Sinus Block  Sinus Arrest  Asystole

Sinus Rhythm Systematic ApproachCharacteristic of this Rhythm RegularYes Rate60 to 100 BPM P-WaveUpright/Uniform/One for every QRS PR-Interval0.12 to 0.20 QRS ComplexLess than 0.12

Sinus Tachycardia Systematic ApproachCharacteristic of this Rhythm RegularYes Rate100 to 150 BPM P-WaveUpright/Uniform/One for every QRS PR-Interval0.12 to 0.20 QRS ComplexLess than 0.12

Sinus Bradycardia Systematic ApproachCharacteristic of this Rhythm RegularYes RateLess than 60 BPM P-WaveUpright/Uniform/One for every QRS PR-Interval0.12 to 0.20 QRS ComplexLess than 0.12

Sinus Arrhythmia Systematic ApproachCharacteristic of this Rhythm RegularNo Rate60 to 100 BPM P-WaveUpright/Uniform/One for every QRS PR-Interval0.12 to 0.20 QRS ComplexLess than 0.12

Sinus Block Systematic ApproachCharacteristic of this Rhythm Regular RateDepends on underlying Sinus Rhythm P-WaveUpright/Uniform/One for every QRS PR-Interval0.12 to 0.20 QRS ComplexLess than 0.12 Comes back in at regular interval!

Sinus Arrest Systematic ApproachCharacteristic of this Rhythm Regular RateDepends on underlying Sinus Rhthm P-WaveUpright/Uniform/One for every QRS PR-Interval0.12 to 0.20 QRS ComplexLess than 0.12 Comes back in at irregular interval!

Asystole Systematic ApproachCharacteristic of this Rhythm RegularN/A Rate0 P-WaveN/A PR-IntervalN/A QRS ComplexN/A

Atrial Rythms  Atrial Fibrillation  Atrial Flutter  Supraventricular Tachycardia (PSVT or SVT)

Atrial Fibrillation Systematic ApproachCharacteristic of this Rhythm RegularNo RateVariable P-WaveUncountable/multiple per QRS PR-IntervalN/A QRS ComplexLess than 0.12

Atrial Flutter Systematic ApproachCharacteristic of this Rhythm RegularP- Yes QRS-Variable RateVariable P-Wave“Saw Tooth Pattern” PR-IntervalN/A QRS ComplexLess than 0.12

Supraventricular Tachycardia PSVT or SVT Systematic ApproachCharacteristic of this Rhythm Regular RateGreater than 150 P-WaveBuried in T-Wave PR-IntervalUnreadable QRS ComplexLess than 0.12

Junctional Rhythms  Junctional Rhythm  Accelerated Junctional Rhythm  Junctional Tachycardia

Junctional Rhythm Systematic ApproachCharacteristic of this Rhythm Regular Rate40 to 60 P-WaveInverted/Absent/after QRS PR-IntervalIf P-Wave Present less than 0.12 QRS ComplexLess than 0.12

Accelerated Junctional Rhythm Systematic ApproachCharacteristic of this Rhythm Regular Rate60 to 100 P-WaveInverted/Absent/after QRS PR-IntervalIf P-Wave Present less than 0.12 QRS ComplexLess than 0.12

Junctional Tachycardia Systematic ApproachCharacteristic of this Rhythm Regular RateGreater than 100 P-WaveInverted/Absent/after QRS PR-IntervalIf P-Wave Present less than 0.12 QRS ComplexLess than 0.12

AV Nodal Blocks  1 st Degree Heart Block  2 nd Degree Heart Block Type I  2 nd Degree Heart Block Type II  3 rd Degree Heart Block

1 st Degree Block Systematic ApproachCharacteristic of this Rhythm Regular Rate Depends on Underlying Rhythm (usually 60 to 100 BPM) P-WaveUniform/Upright/One for every QRS PR-IntervalGreater than 0.20/Constant QRS ComplexLess than 0.12

2 nd Degree Type I Systematic ApproachCharacteristic of this Rhythm RegularRegular w/Occasional Dropped QRS Rate Depends on Underlying Rhythm (usually 60 to 100 BPM) P-WaveUniform/Upright/One for every QRS PR-IntervalGradual Lengthening with each beat QRS ComplexLess than 0.12 (Occasional Dropped QRS)

2 nd Degree Type II Systematic ApproachCharacteristic of this Rhythm RegularRegular w/Occasional Dropped QRS Rate Depends on Underlying Rhythm (usually 60 to 100 BPM) P-WaveUniform/Upright/One for every QRS PR-Interval0.12 to 0.2 w/Consistent with each beat QRS ComplexLess than 0.12 (Occasional Dropped QRS)

3 rd Degree Block Systematic ApproachCharacteristic of this Rhythm RegularRegular P Waves/Regular QRS Rate Depends on Underlying Rhythm (usually 60 to 100 BPM) P-WaveUniform/Upright/Out of Sync with QRS PR-IntervalUnmeasurable QRS ComplexWider than 0.12

Ventricular Rhythms  Ventricular Tachycardia  Ventricular Fibrillation  Torsades De Pointes

Ventricular Tachycardia Systematic ApproachCharacteristic of this Rhythm RegularRegular QRS RateGreater than 150 P-WaveNone PR-IntervalNone QRS ComplexWider than 0.12

Ventricular Fibrillation Systematic ApproachCharacteristic of this Rhythm RegularIrregular QRS RateUnmeasurable P-WaveNone PR-IntervalNone QRS ComplexUnmesurable

Torsades De Pointes Systematic ApproachCharacteristic of this Rhythm RegularIrregular QRS RateGreater than 150 P-WaveNone PR-IntervalNone QRS ComplexGreater than 0.12

Random Escape Rhythms  PAC  PJC  PVC  Unifocal  Multifocal  Couplets  Bigeminal PVC

Premature Atrial Contraction Systematic ApproachCharacteristic of this Rhythm RegularRegular depending on underlying rhythm RateDepends on underlying rhythm P-WaveUpright/uniform/one for every QRS PR-Interval0.12 to 0.20 QRS Complex0.04 to 0.12

Premature Junctional Contraction Systematic ApproachCharacteristic of this Rhythm RegularRegular depending on underlying rhythm RateDepends on underlying rhythm P-WaveUpright/uniform/one for every QRS PR-Interval0.12 to 0.20 QRS Complex0.04 to 0.12

Premature Ventricular Contraction: Unifocal Systematic ApproachCharacteristic of this Rhythm RegularRegular depending on underlying rhythm RateDepends on underlying rhythm P-WaveUpright/uniform/one for every QRS PR-Interval0.12 to 0.20 QRS Complex0.04 to 0.12

Premature Ventricular Contraction: Multifocal Systematic ApproachCharacteristic of this Rhythm RegularRegular depending on underlying rhythm RateDepends on underlying rhythm P-WaveUpright/uniform/one for every QRS PR-Interval0.12 to 0.20 QRS Complex0.04 to 0.12

Premature Ventricular Contraction: Couplets Systematic ApproachCharacteristic of this Rhythm RegularRegular depending on underlying rhythm RateDepends on underlying rhythm P-WaveUpright/uniform/one for every QRS PR-Interval0.12 to 0.20 QRS Complex0.04 to 0.12

Premature Ventricular Contraction: Bigeminal Systematic ApproachCharacteristic of this Rhythm RegularRegular depending on underlying rhythm RateDepends on underlying rhythm P-WaveUpright/uniform/one for every QRS PR-Interval0.12 to 0.20 QRS Complex0.04 to 0.12

12-Leads  Chest Leads  Hypertrophy and Enlargement  Axis Deviation  Bundle Branch Block  Ischemia  Q-Wave  ST-Segment Elevation  Posterior MI

Unipolar Chest Leads  V1 though V6

Ventricular Hypertrophy  Left Ventricular Hypertrophy  Greatest R Wave in Leads V5 or V6 added to the Deepest S-Wave in either V1 or V2  If Greater than 35 mm = positive for LVH OR  R in Lead I and S in Lead III is greater than 25 mm = LVH OR  R in Leads aVR Greater than 12 mm = LVH  Right Ventricular Hypertrophy  In V1  R to S ratio greater than 1 And  Inverted T-Wave Or  R Greater than 6 mm  S less than 2 mm Or  rSR’ with R greater than 10 mm

Atrial Enlargement  Left Atrial Enlargement  Lead II greater than 0.04 sec between two notched peaks on a p- wave OR  V1 negative deflection greater of biphasic P-Wave greater than 1 little box wide and 1 little box deep  Right Atrial Enlargement  Lead II P-wave greater than 2.5 mm tall OR  Lead V1 or V2 P wave greater than 1.5 mm tall

Axis Deviation  Axis Deviation is the net direction that the electrical activity of the heart is flowing and is measured in degrees.  Normal Axis: 0 to 90 degrees  Right Axis: 90 to 180 degrees  Left Axis: Physiologic 0 to -40  Left Axis: Pathologic -40 to -90  Extreme Right Axis Deviation: -90 to -180

Axis Deviation  Equiphasic Approach  Quadrant Approach

Equiphasic Approach  Rules  Step 1: Fine the most Equiphasic QRS in LEAds I, II, III, aVF, aVR, or aVL  Step 2: Look at Hexaxial wheel and find the lead that corresponds with step one.  Step 3: Fine the lead 90 degrees to the lead identified in step two.  Step 4: Identify the lead from step three on the 12-lead and determine if it is upright or negative.  Step 5: If upright, find it on the hexaxial wheel and it’s degree is the axis deviation. Or  Step 5: If negative find it on the hexaxial wheel and it’s degree minus 180 degrees is the axis deviation.

Equiphasic Approach  Step 1: Find the most Equiphasic QRS complex in LEAds I, II, III, aVF, aVR, or aVL  For this 12-Lead it is aVR

Equiphasic Approach  Step 2: Look at Hexaxial wheel and find the lead that corresponds with step one.  aVR was the lead and if you look at the hexaxial wheel it’s aVR is at -150 degrees

Equiphasic Approach  Step 3: Find the lead 90 degrees to the lead identified in step two.  In this case the lead that is 90 degrees to aVR on the Hexaxial Reference System is Lead III.  Lead III is noted to be at 120 degrees.

Equiphasic Approach  Step 4: Identify the lead from step three on the 12-lead and determine if it is upright or negative.  Lead III is noted to be predominantly positive

Equiphasic Approach  Step 5:  If upright, find it on the hexaxial wheel and it’s degree is the axis deviation. OR  If negative find it on the hexaxial wheel and it’s degree minus 180 degrees is the axis deviation.  Lead III was upright so the axis deviation for this 12-lead EKG would be 120 degrees.  If lead III was negative the axis deviation for this 12-lead EKG would be 120 degrees minus 180 which equals -60.

Quadrant Approach  Determine deflection in Lead I and aVF  Upright I/ Upright aVF = Normal Axis Deviation  Upright I/Negative aVF = Left Axis Devation  Negative I / Upright aVF = Right Axis Deviation  Negative I / Negative aVF = Extreme Right Axis Deviation or “No Mans Land”

Quadrant Approach: left axis deviation  If axis deviation is determined to be LAD do the following:  Look at lead II  If positive or equiphasic then it is physiologic Left Axis Deviation OR  If negative then it is pathologic Left Axis Deviation

Bundle Branch Block  LBBB  RBBB

Left Bundle Branch Block  Rules  QRS is greater than 0.12  Look at V1 and determine if the terminal portion of the QRS is positive or negative  If negative = LBBB

Right Bundle Branch Block  Rules  QRS greater than 0.12  Look at V1 and determine if the terminal portion of the QRS is positive or negative  If Positive= RBBB

“Contiguous Leads”  I (Inferior)  See (Septal)  All (Anterior)  Leads (Lateral) Inferior (II, III, aVF) Septal (V1,V2) Anterior (V3,V4) Lateral (V5, V6, Lead I, and aVL)

Q-Wave Importance  If a significant Q- Wave is present this indicates prior injury to the heart

Myocardial Ischemia  ST Segment Depression of 1 mm or more in contiguous leads = Ischemia to the heart  Here II, III, aVF, and V3 through V6 shows ST Segment Depression.  So this would be InferoSeptoLateral ischemia.

Myocardial Infarction  ST- Segment Elevation of 1 mm in two contiguous leads.

Anterior MI

Lateral MI

Inferior MI  Commonly has Right sided involvement

Septal MI

Posterior MI  Suspect Posterior MI if you have an Inferior  Look at Leads V1/V2  No ST Segment Elevation is Present  V1/V2 have significant ST Depression  Flip the Paper upside down  After flipping the paper upside down, if Elevation is present in V1 and V2 w/q-wave this is likely a Posterior MI