ECG- Reading and Interpretation

Slide 1: 

The Reading & Interpretation of ECG

Dr V.Dharma Rao: 

Dr V.Dharma Rao Associate Professor of General Medicine Mamata Medical College -------------------- Khammam

Slide 3: 

ECG for Non-Cardiologists:

Slide 4: 

Approaching the Patient

Slide 5: 

“See what you see!” “People look, but they don’t see” …A. Fowler, Jr.

Slide 6: 

The most common investigation In cardiology. . . Electrocardiogram

Slide 7: 

Let’s consider the following uninterpreted EKG :

Slide 9: 

Your diagnosis ? a. “ I think it’s OK ” b. Wait for cardiology to confirm ? How should it / might it affect your anesthetic plan? a. Delay case ? b. Cancel case ? c. Proceed based upon surgeon’s request ? d. Consult with other anesthesia team member (MDA) & proceed accordingly ?

HOW TO READ ECG: 

HOW TO READ ECG Rate Rhythm Axis Chamber enlargement & hypertrophy Arrythmias & conduction delays Ischaemia / infarction

Slide 11: 

Cardiac Anatomy

Slide 13: 

Circumflex L eft C oronary A rtery L eft A nterior D escending R ight C oronary A rtery Sinus Artery

Slide 14: 

R ight C oronary A rtery P osterior D escending C oronary A rtery Circumflex

Slide 15: 

Right Coronary Artery Posterior Descending Circumflex Right Dominant Coronary Circulation

Slide 16: 

Circumflex Lateral MI

Slide 17: 

Right Coronary Artery Posterior MI

Slide 18: 

Posterior Descending Inferior MI

Slide 19: 

Left Anterior Descending Anterior MI

Slide 20: 

Conduction System

Slide 21: 

S-A Node A-V Node Bundle of His RCA / Cx

Slide 22: 

LAD Right Bundle Branch Purkinje Fibers Posterior Fascicle Anterior Fascicle

Slide 23: 

ECG

Components of the ECG: 

Components of the ECG R Wave

What do those bumps mean?: 

P Wave – atrial electrical activity/contraction What do those bumps mean? Atrial activity

What do those bumps mean?: 

PR Interval – time between atrial to ventricular electrical activity What do those bumps mean? Atrial activity

What do those bumps mean?: 

QRS Complex – ventricular electrical activity/contraction What do those bumps mean? Atrial activity Ventricular activity

What do those bumps mean?: 

T Wave – ventricular “recharging” What do those bumps mean? Atrial activity Ventricular activity “Resetting”

What do those bumps mean?: 

QT Interval – represents “recharging” of the electrical system of the heart What do those bumps mean? Atrial activity Ventricular activity “Resetting”

Putting It Together: 

Putting It Together

ECG waves and intervals: 

ECG waves and intervals QT interval: duration of ventricular depolarization and repolarization RR interval: duration of ventricular cardiac cycle (an indicator of ventricular rate) PP interval: duration of atrial cycle (an indicator or atrial rate) PR interval: time interval from onset of atrial depolarization (P wave) QRS duration: duration of ventricular muscle depolarization P wave: the sequential activation (depolarization) of the right and left atria QRS complex: right and left ventricular depolarization (normally the ventricles are activated simultaneously )

How do we obtain an ECG?: 

How do we obtain an ECG?

What are leads?: 

What are leads? Leads are a series of electrodes which measure the difference in electrical activity between 2 points. Leads are placed at specific points on the arms, legs and thorax that sense and record the heart’s electrical activity.

The “Limb” Leads: 

The “Limb” Leads “Frontal” Leads

Chest Wall Leads: 

Chest Wall Leads “Precordial” Leads

12 Lead ECG: 

12 Lead ECG

Anatomy and ECG (Septal Wall): 

Anatomy and ECG ( Septal Wall)

Anatomy and ECG (Anterior Wall): 

Anatomy and ECG (Anterior Wall)

Anatomy and ECG (Lateral Wall): 

Anatomy and ECG (Lateral Wall)

Anatomic Groups (Inferior Wall): 

Anatomic Groups (Inferior Wall)

Determining Heart Rate: 

Determining Heart Rate

Determining the Heart Rate: 

Determining the Heart Rate Rule of 300 10 Second Rule

Rule of 300: 

Rule of 300 Take the number of “big boxes” between neighboring QRS complexes, and divide this into 300. The result will be approximately equal to the rate Although fast, this method only works for regular rhythms.

What is the heart rate?: 

What is the heart rate? (300 / 6) = 50 bpm www.uptodate.com

What is the heart rate?: 

What is the heart rate? (300 / ~ 4) = ~ 75 bpm www.uptodate.com

What is the heart rate?: 

What is the heart rate? (300 / 1.5) = 200 bpm

The Rule of 300: 

The Rule of 300 It may be easiest to memorize the following table: # of big boxes Rate 1 300 2 150 3 100 4 75 5 60 6 50

10 Second Rule: 

10 Second Rule As most EKGs record 10 seconds of rhythm per page, one can simply count the number of beats present on the EKG and multiply by 6 to get the number of beats per 60 seconds. This method works well for irregular rhythms.

What is the heart rate?: 

What is the heart rate? 33 x 6 = 198 bpm The Alan E. Lindsay ECG Learning Center ; http://medstat.med.utah.edu/kw/ecg/

Interpreting EKG Axis: 

Interpreting EKG Axis

The QRS Axis: 

The QRS Axis The QRS axis represents the net overall direction of the heart’s electrical activity. Abnormalities of axis can hint at: Ventricular enlargement Conduction blocks (i.e. hemiblocks)

The QRS Axis: 

The QRS Axis By near-consensus, the normal QRS axis is defined as ranging from -30 ° to +90 ° . -30 ° to -90 ° is referred to as a left axis deviation (LAD) +90 ° to +180 ° is referred to as a right axis deviation (RAD)

Determining the Axis: 

Determining the Axis The Quadrant Approach The Equiphasic Approach

Determining the Axis: 

Determining the Axis

Determining the Axis: 

Determining the Axis Predominantly Positive Predominantly Negative Equiphasic

The Quadrant Approach: 

The Quadrant Approach 1. Examine the QRS complex in leads I and aVF to determine if they are predominantly positive or predominantly negative. The combination should place the axis into one of the 4 quadrants below.

The Quadrant Approach: 

The Quadrant Approach 2. In the event that LAD is present, examine lead II to determine if this deviation is pathologic. If the QRS in II is predominantly positive, the LAD is non-pathologic (in other words, the axis is normal). If it is predominantly negative, it is pathologic.

Quadrant Approach: Example 1: 

Quadrant Approach: Example 1 Negative in I, positive in aVF  RAD The Alan E. Lindsay ECG Learning Center http://medstat.med.utah.edu/kw/ecg/

Quadrant Approach: Example 2: 

Quadrant Approach: Example 2 Positive in I, negative in aVF  Predominantly positive in II  Normal Axis (non-pathologic LAD) The Alan E. Lindsay ECG Learning Center http://medstat.med.utah.edu/kw/ecg/

The Equiphasic Approach: 

The Equiphasic Approach 1. Determine which lead contains the most equiphasic QRS complex. The fact that the QRS complex in this lead is equally positive and negative indicates that the net electrical vector (i.e. overall QRS axis) is perpendicular to the axis of this particular lead. 2. Examine the QRS complex in whichever lead lies 90° away from the lead identified in step 1. If the QRS complex in this second lead is predominantly positive, than the axis of this lead is approximately the same as the net QRS axis. If the QRS complex is predominantly negative, than the net QRS axis lies 180° from the axis of this lead.

Equiphasic Approach: Example 1: 

Equiphasic Approach: Example 1 Equiphasic in aVF  Predominantly positive in I  QRS axis ≈ 0° The Alan E. Lindsay ECG Learning Center ; http://medstat.med.utah.edu/kw/ecg/

Equiphasic Approach: Example 2: 

Equiphasic Approach: Example 2 Equiphasic in II  Predominantly negative in aVL  QRS axis ≈ +150° The Alan E. Lindsay ECG Learning Center ; http://medstat.med.utah.edu/kw/ecg/

Slide 66: 

Hexaxial Array for Axis Determination determination of the angle of the HEART AXIS in the frontal plain

Slide 67: 

Lead I If lead I is mostly positive, the axis must lie in the right half of of the coordinate system (the main vector is moving mostly toward the lead’s positive electrode) Hexaxial Array for Axis Determination – Example 1

Slide 68: 

If lead AVF is mostly positive, the axis must lie in the bottom half of of the coordinate system (again, the main vector is moving mostly toward the lead’s positive electrode Lead AVF Hexaxial Array for Axis Determination – Example 1

Slide 69: 

Hexaxial Array for Axis Determination – Example 1 I AVF Combining the two plots, we see that the axis must lie in the bottom right hand quadrant

Slide 70: 

I AVF AVL Hexaxial Array for Axis Determination – Example 1 Once the quadrant has been determined, find the most equiphasic or smallest limb lead. The axis will lie about 90 o away from this lead. Given that AVL is the most equiphasic lead, the axis here is at approximately 60 o .

Slide 71: 

Hexaxial Array for Axis Determination – Example 1 Since QRS complex in AVL is a slightly more positive, the true axis will lie a little closer to AVL (the depolarization vector is moving a little more towards AVL than away from it). A better estimate would be about 50 o (normal axis). I AVF AVL

Slide 72: 

EKG with a Normal Axis.

Slide 73: 

Hexaxial Array for Axis Determination – Example 2 Lead I If lead I is mostly negative, the axis must lie in the left half of of the coordinate system.

Slide 74: 

Hexaxial Array for Axis Determination – Example 2 Lead AVF If lead AVF is mostly positive, the axis must lie in the bottom half of of the coordinate system

Slide 75: 

I AVF Combining the two plots, we see that the axis must lie in the bottom left hand quadrant (Right Axis Deviation) Hexaxial Array for Axis Determination – Example 2

Slide 76: 

Hexaxial Array for Axis Determination – Example 2 I AVF II Once the quadrant has been determined, find the most equiphasic or smallest limb lead. The axis will lie about 90 o away from this lead. Given that II is the most equiphasic lead, the axis here is at approximately 150 o .

Slide 77: 

Hexaxial Array for Axis Determination – Example 2 I AVF II Since the QRS in II is a slightly more negative, the true axis will lie a little farther away from lead II than just 90 o (the depolarization vector is moving a little more away from lead II than toward it). A better estimate would be 160 o .

Extreme RAD: 

Extreme RAD If lead I is negative AND aVF is also negative – extreme RAD Clue: If aVR is positive = extreme RAD This is seen with rare situations such as VT or Pacemakers In general we should never have an axis over here!

Slide 81: 

EKG with Right Axis Deviation

EKG Axis Summary: 

EKG Axis Summary look at lead I and aVF : if both are positive = Normal axis If I is positive but aVF is negative = probable LAD If between 0 ° & – 30 ° = upper limits of normal If between – 30 ° & – 90 ° = True LAD (check lead II to determine) If I is negative = RAD (axis > 90 ° )…you can be more specific and decide: If between +90 & +120 = upper limits of normal If between +120 to +180 = True RAD When both I & aVF are negative, axis is between -90 and +/-180 – this is Extreme RAD

Finally: EKG Axis for Dummies!: 

Lead I = left thumb and aVF = right thumb If both I & aVF are up = Normal Axis If I is up but aVF is down = LAD If I is down but aVF is up = RAD If both I & aVF are down = Extreme RAD Finally : EKG Axis for Dummies!

Slide 84: 

Since Lead III is the most equiphasic lead and it is slightly more positive than negative, this axis could be estimated at about 40 o . Precise calculation of the axis can be done using the coordinate system to plot net voltages of perpendicular leads, drawing a resultant rectangle, then connecting the origin of the coordinate system with the opposite corner of the rectangle. A protractor can then be used to measure the deflection from 0. Net voltage = 12 Net voltage = 7 Precise Axis Calculation

Slide 85: 

Chamber enlargement & hypertrophy

LVH: 

ESTES Criteria for LVH ("diagnostic", > 5 points; "probable", 4 points) ECG Criteria Points R or S in limb leads > 20mm S in V1 or V2 > 30mm R in V5 or V6 > 30mm Any criteria positive 3 points ST – T abnormalities Without digoxin With digoxin 3 points 1 point Left Atrial Enlargement inV1 3 points Left Axis Deviation 2 points QRS duration 0.09sec 1 point Delayed intrinsicoid deflection in V5 or V6 > 0.05SEC 1 point LVH

RVH : 

RVH V1 Lead: - R/S ratio > 1 and negative T wave - R > 6 mm, or S < 2mm, - rSR' with R' >10 mm R in V1 + S in V5 (or V6) > 10 mm V5 or V6 - R/S ratio in V5 or V6 < 1 - R in V5 or V6 < 5 mm - S in V5 or V6 > 7 mm

LAE: 

LAE Sensitivity = 50%; Specificity = 90% P wave duration > 0.12s in frontal plane (usually lead II) Terminal P negativity in lead V1 (i.e., "P-terminal force") duration > 0.04s, depth > 1 mm.

RAE : 

RAE P wave amplitude >2.5 mm in II and/or >1.5 mm in V1 (Sensitivity = 50%; Specificity = 90%) QRS voltage in V1 is <5 mm and V2/V1 voltage ratio is >6 (Sensitivity = 50%; Specificity = 90%)

Slide 91: 

CONDUCTION BREAK

Slide 93: 

“Well, Mr Rajesh, You have heart block.” “What is that” “ Traffic jam in the conduction system of the heart. “

Slide 94: 

1 º 2º 3º Superspeciality in cardiology !!!

Slide 96: 

AV Heart Blocks Pauline Seydak, Cardiac Physiology Trainer N.I.

AV Nodal Blocks (heart blocks): 

AV Nodal Blocks (heart blocks) Disturbances of the conduction through the heart, occurring at the AV Node AV Node – damaged/diseased – delay or total block of impulses at the AV Node This conduction defect can be seen on the ECG

Slide 98: 

1- All the time (but taking a little longer than usual). 2- Some of the time. 3- None of the time. All, some, or none of the time. And see, those are the three kinds, or degrees of heart block: first, second, and third degree. All, some, or none. Here’s the key idea - the signal is either getting through:

AV Node: 

AV Node AV nodal conduction time is represented on the ECG as the PR segment. But - we always measure the PR interval.

First Degree Heart Block (1º): 

First Degree Heart Block (1 º) SA Node – normal Normal P wave AV Node conducts more slowly than normal Prolonged PR Interval Rest of conduction is normal Normal QRS

First Degree Heart Block (1º): 

First Degree Heart Block (1 º) PR Interval > 0.2 seconds (5 small sq) Note – the PR Interval is constant

Significance: 

Significance Clinical significance None Note – this can progress to 2 º or 3º heart block

Second Degree Heart Block (2º): 

Second Degree Heart Block (2 º) Mobitz Type I (Wenkebach) Mobitz Type II 2 : 1

Second Degree Heart Block (2º) Mobitz Type I (Wenkebach): 

Second Degree Heart Block (2 º) Mobitz Type I (Wenkebach) PR Interval prolongs with each beat until a dropped beat is seen The PR Interval is NOT constant After each dropped beat, the PR interval is normal and the cycle starts again

Second Degree Heart Block (2º) Mobitz Type I (Wenkebach): 

Second Degree Heart Block (2 º) Mobitz Type I (Wenkebach) PR PR PR DROPPED BEAT

Slide 107: 

2 nd Degree AV block Mobitz 1

Second Degree Heart Block (2º) Mobitz Type II : 

Second Degree Heart Block (2 º) Mobitz Type II Conduction through the AV node is constant. PR interval is normal and constant Occasionally a dropped beat is seen

Second Degree Heart Block (2º) Mobitz Type II : 

Second Degree Heart Block (2 º) Mobitz Type II PR PR DROPPED BEAT PR

Second Degree Heart Block (2º) 2 : 1: 

Second Degree Heart Block (2 º) 2 : 1

Third Degree Heart Block (3º) (Complete): 

Third Degree Heart Block (3 º) (Complete) Complete failure of the AV Node No impulses from Sinus Node will pass through to the ventricles Some part if the conducting system will take over as pacemaker of the heart (even a myocardial cell 10-15 bpm)

Third Degree Heart Block (3º) (Complete): 

Third Degree Heart Block (3 º) (Complete) P wave rate – normal Ventricular rate – slow Ventricular complex may be broad Idioventricular rhythm Complete dissociation between P waves & QRS

Third Degree Heart Block (3º) (Complete): 

Third Degree Heart Block (3 º) (Complete) P P P P P QRS QRS

Slide 115: 

3 rd degree AV block

Summary: 

Summary 1 º - prolongation of PR Interval ALL 2º - Mobitz I – Increasing PR Interval until dropped beat is seen SOME Mobitz II – Constant PR Interval with more P waves to QRS 2 : 1 – Constant PR Interval with more P waves to QRS 3º - Complete dissociation between P waves & QRS NONE

Bundle Branches: 

Bundle Branches Normal conduction speed through the bundles is about 0.1 seconds

Bundle Branch Block: 

Bundle Branch Block Consider a blocked or slowed branch or bundle Right Left

Right Bundle Branch Block: 

Right Bundle Branch Block 1. r wave in V1 q wave in V6 2. S wave in V1 R wave in V6 3. R’ wave in V1 S wave in V6 1. 2. 3.

Right Bundle Branch Block Criteria: 

Right Bundle Branch Block Criteria V 1 or V 2 = rSR ’ - “M” or rabbit ear shape V 5 or V 6 = qRS Large R waves Right chest leads: T wave inversion (“secondary changes” since they reflect a delay in depolarization not an actual change in depolarization). Complete RBBB: QRS > 0.12 sec. Incomplete RBBB: QRS = 0.10 to 0.12 sec.

Right Bundle Branch Block: 

Right Bundle Branch Block V 1 = rSR’ V 6 = qRS

Right Bundle Branch Block: 

Right Bundle Branch Block V 2 = rSR’ V 6 = qRS

Left Bundle Branch Block: 

Left Bundle Branch Block 1. r wave in V1 R wave in V6 2. S wave in V1 R wave in V6

Left Bundle Branch Block: 

Left Bundle Branch Block Loss of septal R in V1 and septal Q in V6. Wide QRS Negative in V1 Positive in V6

Left Bundle Branch Block Criteria: 

Left Bundle Branch Block Criteria Wide QRS complex V1 = QS (or rS ) and may have a “W” shape to it. V6 = R or notched R showing a “M” shape or rabbit ears Secondary T wave inversion Secondary if in lead with tall R waves Primary if in right precordial leads

Left Bundle Branch Block: 

Left Bundle Branch Block

RBBB versus LBBB: 

RBBB versus LBBB ? ?

Incomplete Bundle Branch Blocks: 

Incomplete Bundle Branch Blocks RBBB or LBBB where QRS is between .10 and .12 with same QRS features Incomplete RBBB normal variant Incomplete LBBB a progression of LVH

Intraventricular Delay or Intraventricular Conduction Defect: 

Intraventricular Delay or Intraventricular Conduction Defect General term for wide QRS complexes that are not typical of RBBB or LBBB

Pacemaker Pattern: 

Pacemaker Pattern

Pacemaker Patterns: 

Pacemaker Patterns

Trifascicular Conduction System: 

Trifascicular Conduction System

Tri-fascicular Conduction System: 

Tri-fascicular Conduction System Right bundle Left anterior (superior) fascicle Left posterior (inferior) fascicle Fascicular block (or hemiblock) = a block in either the LAF or LPF.

Fascicular Blocks: 

Fascicular Blocks Fascicular blocks only slightly prolongs the QRS. Fascicular blocks cause axis deviation as do infarcts and hypertrophy. Left or right axis deviation without signs of infarct or hypertrophy are fascicular blocks.

Left Anterior Fascicular Block: 

Left Anterior Fascicular Block Limb leads QRS less width less than 0.12 sec. QRS axis = Left axis deviation (-45° or more) if S wave in aV F is greater than R wave in lead I small Q wave in lead I, aV L , or V 6

Left Posterior Fascicular Block: 

Left Posterior Fascicular Block Right axis deviation (QRS axis +120° or more) S wave in lead I and a Q wave in lead III (S1Q3) Rare

Bifascicular Block: 

Bifascicular Block Two of the three fascicles are blocked. Most common is RBBB with left anterior fascicular block.

Slide 141: 

“And that, in simple terms, How to diagnose bundle branch blocks.”

Slide 142: 

RBBB or LBBB..

Slide 144: 

Forget about the notch! Rabbit ears are for rabbits not EKGs!! Look for widened QRS (>120ms) in ANY lead (3 little boxes) This is an indication of aberrant ventricular conduction Always measure - Don’t trust your eyes!!

Slide 145: 

Measure widest QRS with discernible beginning and ending Look for evidence of atrial activity producing QRS complexes Then try to determine LBBB from RBBB

Slide 146: 

Defining a BBB must be done in V1 Complex must be atrial in origin Determine the terminal force of the QRS complex Locate the J point Determine if the last electrical activity produced a upward or downward deflection

Bundle Branch Block: 

Bundle Branch Block Determine direction of terminal force Find J point Did last electrical activity produce an upward or downward deflection?

Bundle Branch Block: 

Bundle Branch Block RBBB will produce upward terminal force deflection LBBB will produce downward terminal force deflection

Bundle Branch Block: 

Bundle Branch Block What’s the story with this EKG?

Bundle Branch Block: 

Bundle Branch Block Notice how this EKG differs from the previous one

Bundle Branch Block: 

Bundle Branch Block Turn Signal Method R. turn push up L. turn push down RBBB = up LBBB = down

Bundle Branch Block: 

Bundle Branch Block Exception to the rule Sensitivity and Specificity Junction rhythms - sensitivity Wolf-Parkinson-White - specificity

Slide 156: 

No, this is sensex

Myocardial Infarction: 

Myocardial Infarction

Myocardial Infarction: 

Myocardial Infarction Process of Infarction Changes in EKG During Infarction Site and Extent of Infarction Right Ventricular Infarction Posterior Wall Infarction

Process of Infarction: 

Process of Infarction Infarction strictly refers to necrosed tissue from ischemia AHA suggest infarction as a “process” Occurs when coronary artery can’t supply tissue Can result from thrombus, spasm, etc.

Process of Infarction: 

Process of Infarction Ischemia Temporary shortage of O 2 at cellular level Usually results from narrowed coronary artery Pain results as O 2 demand exceeds supply

Process of Infarction: 

Process of Infarction Injury Occurs as O 2 levels fall short of demand Cells are still alive, but will die if condition not corrected Can produce pump dysfunction or electrical conduction defects Necrosis Cellular death

Changes in EKG During Infarction: 

Changes in EKG During Infarction Morphology vs. Rhythm Focus change from just rate & rhythm Morphologic changes help identify infarction Predictable changes are observed during an infarction in progress These are known as “Indicative Changes”

Changes in EKG During Infarction: 

Changes in EKG During Infarction Development of Tall “T” Waves Denotes ischemic cardiac tissue Becomes more symmetrical May become pointed Sometimes referred to as “Tombstone” T waves Occurs during first few minutes of infarction Described as the “Hyperacute Phase” of infarction

Changes in EKG During Infarction: 

Changes in EKG During Infarction Example of Tall T Waves Observed in Hyperacute phase of Myocardial Infarction

Changes in EKG During Infarction: 

Changes in EKG During Infarction T Wave Inversion Denotes ischemic cardiac tissue May be seen in patients suffering from stable angina pectoris May be seen in patients suffering from acute infarction

Changes in EKG During Infarction: 

Changes in EKG During Infarction Example of T Wave Inversion Observed During Cardiac Ischemia

Changes in EKG During Infarction: 

Changes in EKG During Infarction ST segment elevation Hallmark sign of infarction Denotes infarction in progress Occurs during first few hours of the infarction process Described as the “Acute Phase” of infarction

Changes in EKG During Infarction: 

Changes in EKG During Infarction Example of ST Segment Elevation Observed During Myocardial Infarction

Changes in EKG During Infarction: 

Changes in EKG During Infarction Pathological Q Wave Development Denotes Myocardial Necrosis Greater than 40 ms wide is considered pathological - (one small box or more wide) Occurs in the first few to several hours Occurs later in the “Acute Phase” of infarction

Changes in EKG During Infarction: 

Changes in EKG During Infarction Example of Pathological Q Wave Development Observed During Myocardial Infarction

Changes in EKG During Infarction: 

Changes in EKG During Infarction What happens after the infarction process ends?

Changes in EKG During Infarction: 

Changes in EKG During Infarction Pathological Q waves remain Possible to detect previous infarction from this sign Not possible to determine when the infarction occurred

Site and Extent of Infarction: 

Site and Extent of Infarction Indicative Changes - Signs of Infarction Will not be in every lead Will only be seen in those leads which “look” at the infarction site

Site and Extent of Infarction: 

Site and Extent of Infarction To suspect infarction--- indicative changes must occur in 2 or more “anatomically contiguous” leads

Site and Extent of Infarction: 

Site and Extent of Infarction Localization is Important II, III, aVF observes the Inferior Wall V 1, V 2 observes the Septal Wall V 3, V 4 observes the Anterior Wall V 5, V 6, I, aVL observes the Lateral Wall aVR “No Man’s Land”

Site and Extent of Infarction: 

Site and Extent of Infarction Question??? Where is the patient’s infarction occurring in the above EKG???

Site and Extent of Infarction: 

Site and Extent of Infarction Inferior Wall Infarction!! Simple, huh!!!!!

Site and Extent of Infarction: 

Site and Extent of Infarction Assessing the Extent of Infarction How many leads show indicative changes? D - Massive Infarct V 1 - V 6 , aVL, I C - Lateral Wall V 5 - V 6 , aVL, I

Site and Extent of Infarction: 

Site and Extent of Infarction Assessing the Extent of Infarction How many leads show indicative changes? B - Anterioseptal Infarct V 1 - V 4 A - Anterior Wall V 3 - V 4

Site and Extent of Infarction: 

Site and Extent of Infarction Assessing the Extent of Infarction How many leads show indicative changes? A & B - Inferior Wall II, III, aVF C - Posterioinferior Wall II, III, aVF

Site and Extent of Infarction: 

Site and Extent of Infarction 8 of 12 leads look at tissue supplied by the Left Coronary Incomplete view of tissue supplied by the Right Coronary What about Right Ventricular Infarction??

Right Ventricular Infarction: 

Right Ventricular Infarction Old Thinking RVI of little significance “out of sight out of mind” New Thinking 40% of inferior infarct are complicated by RVI RVI is significant because both ventricles are usually involved

Right Ventricular Infarction: 

Right Ventricular Infarction So... How do we find RVI?? Place electrodes in the precordial positions on the right chest wall V 3 Right - V 6 Right

Right Ventricular Infarction: 

Right Ventricular Infarction V 3 R - V 6 R allow us to observe: Right Anterior Wall Right Lateral Wall Septal wall observed by V 1 and V 2 How many electrodes do I need!!???

Right Ventricular Infarction: 

Right Ventricular Infarction Simple alternative to detect RVI Obtain V 4 R 90% accurate and specific for RVI

Right Ventricular Infarction: 

Right Ventricular Infarction So, when should I check V 4 R? Indicative changes in II, III, aVF

Posterior Wall Infarction: 

Posterior Wall Infarction None of the standard electrodes see the posterior wall Can’t directly use same clues of infarction for posterior wall So Now What??!!

Posterior Wall Infarction: 

Posterior Wall Infarction Look for reciprocal changes Inverse of indicative changes Electrical view from opposite perspective Inferior Wall is reciprocal to Lateral Wall Anterior Wall is reciprocal to Posterior Wall

Posterior Wall Infarction: 

Posterior Wall Infarction Where is this patients infarction occurring? Notice how the lateral leads show the inverse of what is seen in the inferior leads.

Posterior Wall Infarction: 

Posterior Wall Infarction Understanding reciprocal changes is key to recognition of posterior infarction Look for reciprocal changes in V 1 , V 2 , V 3 Look for tall R waves, and ST segment depression

Posterior Wall Infarction: 

Posterior Wall Infarction Example of posterior wall infarction

Where is the ST Elevation?: 

Where is the ST Elevation?

“I See All Leads”: 

“ I See All Leads” I Lateral aVR V1 Septal V4 Anterior II Inferior aVL Lateral V2 Septal V5 Lateral III Inferior aVF Inferior V3 Anterior V6 Lateral

Where is the ST Elevation?: 

Where is the ST Elevation?

“I See All Leads”: 

“I See A ll Leads” I Lateral aVR V1 Septal V4 Anterior II Inferior aVL Lateral V2 Septal V5 Lateral III Inferior aVF Inferior V3 Anterior V6 Lateral

Slide 198: 

So, can the previous 12 lead be called a septal MI as well as an anterior MI? By definition, no. To diagnose septal MI, the ST elevation MUST be in V1 AND V2. HOWEVER, both the septal and anterior walls are fed by the LAD, thus it is logical that we would see changes in the septal leads as well. After all, the “walls” of the heart aren’t actual walls separate from one another. Anterior and septal MI’s often have what is termed “extension” into the wall sharing the same blood supply, the LAD. The previous EKG would often be called an anterioseptal MI

Where is the ST Elevation?: 

Where is the ST Elevation?

“I See All Leads”: 

“I S ee All Leads” I Lateral aVR V1 Septal V4 Anterior II Inferior aVL Lateral V2 Septal V5 Lateral III Inferior aVF Inferior V3 Anterior V6 Lateral

Where is the ST Elevation?: 

Where is the ST Elevation?

“I See All Leads”: 

“I See All L eads” I Lateral aVR V1 Septal V4 Anterior II Inferior aVL Lateral V2 Septal V5 Lateral III Inferior aVF Inferior V3 Anterior V6 Lateral

Slide 204: 

Medical Student: What do you call two orthopedic surgeons reading an EKG? A double-blind study.

Infarct or Not?: 

Infarct or Not?

Infarct or Not?: 

Infarct or Not? Infarction Impostors! Left Bundle Branch Block Ventricular Rhythms Left Ventricular Hypertrophy Pericarditis Early Repolarization

Infarct or Not?: 

Infarct or Not? Left Bundle Branch Block ST elevation in downward deflected leads Usually V 1 - V 3 QRS >120 ms This one can be hard to determine!

Infarct or Not?: 

Infarct or Not? Ventricular Rhythms ST elevation in downward deflected leads Wide QRS Pacemaker Spikes

Infarct or Not?: 

Infarct or Not? Note the wide QRS complexes and pacemaker spikes

Infarct or Not?: 

Infarct or Not? Left Ventricular Hypertrophy ST elevation in downward deflected leads Usually V 1 - V 3 Choose deepest S wave from V 1 & V 2 Choose tallest R wave from V 5 & V 6 Add mm of these deflections Suspect LVH if total >= 35mm

Infarct or Not?: 

Infarct or Not? Left Ventricular Hypertrophy Note the deep S waves in V 1 - V 3

Infarct or Not?: 

Infarct or Not? Pericarditis ST elevation in multiple leads ST elevation not in anatomical grouping PR interval depression Notching of the J point

Infarct or Not?: 

Infarct or Not? Pericarditis Notice the diffuse ST elevation in all leads

Infarct or Not?: 

Infarct or Not? Early Repolarization ST elevation particularly in anterior or anteriolateral leads Tall T waves Notching of the J point

Infarct or Not?: 

Infarct or Not? Early Repolarization Normal variant - Pt.may be asymptomatic Most common in young adults and black males

Infarct or Not?: 

Infarct or Not? Early Repolarization Note the notching at the J point and tall T waves

Infarct or Not?: 

Infarct or Not? Can be difficult to determine cause of ST elevation May require hours of serial EKGs Not reasonable to expect single EKG to always provide adequate information Sometimes, “I don’t know” is the most intelligent response.

Hypertrophy In The Presence of Bundle Branch Block: 

Hypertrophy In The Presence of Bundle Branch Block RVH and RBBB RAD is typically seen; also look for RAE and its peaked P waves. RBBB with RAD indicates RVH is likely present, too. LVH and RBB usual criteria can be used but also look for LAE

Slide 222: 

Dysrhythmia Recognition

Cardiac Dysrhythmias ( incidence ): 

Cardiac Dysrhythmias ( incidence ) 16.3% - 84% for both cardiac & noncardiac surgery “serious arrhythmias” < 1% What’s important here is how you define “serious” ( e.g., VT, VF vs outcome )

Forrest JB et al. Anesth 76 : 3 : 1992 Multicenter Study of General Anesthetics involving 17,201 patients: 

Forrest JB et al. Anesth 76 : 3 : 1992 Multicenter Study of General Anesthetics involving 17,201 patients When the etiology of severe adverse outcomes are assessed ….. Cardiac arrhythmias account for ~ 44% ( 372 of 847 ) poor outcomes !

Most Common Dysrhythmias Under Anesthesia: 

Most Common Dysrhythmias Under Anesthesia PACs bradycardias nodal rhythms simple PVCs In children  SVT ( not under anesthesia )

Factors Precipitate Dysrhythmias: 

Factors Precipitate Dysrhythmias Ischemia / hypoxemia acidosis / alkalosis electrolyte abnormalities increase catecholamines drug toxicities hypothermia Anesthetics volatile , opioids

Guidelines: Rhythm Analysis: 

Guidelines: Rhythm Analysis overall rhythm regular ? reasons for irregular rhythm ….

Reasons for Irregular Heart Rates ( R to R intervals are inconsistent ): 

Reasons for Irregular Heart Rates ( R to R intervals are inconsistent ) Discharge rate from primary pacemaker site is occurring at an irregular interval ( Sinus dysrhythmia ) Premature extrasystoles are interrupting an otherwise regular pattern ( PACs , PJCs ) Periods of cessation of electrical activity ( sinus pause , sinus exit block )

Guidelines: Rhythm Analysis: 

Guidelines: Rhythm Analysis overall rhythm regular ? determine HR ( atrial & vent ) morphology p - waves pr - intervals / are they fixed ? relationship between p - waves & QRS morphology QRS ( shape & width )

Slide 230: 

Sinus Tach or PSVT, Afib, Aflutter, MAT, or VTach THE ONLY PROBLEM IS TELLING THE DIFFERENCE!!

Slide 231: 

Many medics are not adept at EKG interpretation WHY???

Slide 232: 

Because many EKG courses are too long, too boring, and teach difficult concepts to medics who will never use that information

Slide 234: 

Rhythm Strip Interpretation Anatomically speaking...

Slide 235: 

The first thing you do is to perform a “primary survey” of the EKG strip

Slide 236: 

Rate Rate Rate Rate R A T E ! ! !

Slide 237: 

IMPORTANT: Sinus tachycardia with a rate of 150 or above and PAT/PSVT look very similar PAT/PSVT are not usually life threatening except in the rare setting of a patient having myocardial ischemia (chest pain, diaphoresis, or dyspnea)

Slide 238: 

Even More Important: When you can’t tell if a rhythm is sinus tachycardia or PAT/PSVT, be wary of the more serious cause It may be difficult, or even impossible, to see any irregularity in very fast atrial fibrillation

Slide 239: 

Always explain a tachycardia... Corollary: Don't depend on the presence of a tachycardia to determine that an emergency is present

Slide 240: 

Sinus Tachycardia: A “physiological response”

Slide 241: 

Remember: The Maximum Sinus Tachycardia for a patient is about 220 - age

Slide 242: 

What is this rhythm? Correct answer: “It COULD be sinus tach” 220 – 55 = 165

Slide 243: 

If you forget everything else that I say: Remember that patients having near maximum sinus tachycardia at rest are dying!

Slide 244: 

Hemorrhagic shock Sepsis Tension Tamponade Ruptured aorta Ruptured ectopic Massive P.E. Something mobilizing a massive physiological response

Slide 245: 

Your job is to determine if a rapid rhythm MAY be sinus tach If it is, you must take action

Slide 246: 

What is this rhythm? 220 – 60 = 160 Correct answer: “This HAS to be an arrhythmia

Slide 247: 

Regularity

Slide 248: 

Is there Regular Irregularity or Irregular Irregularity?

Slide 249: 

Is there Regular Irregularity: Bigeminy/Trigeminy Wenckebach The “guy with a limp”

Slide 250: 

Regular Irregularity: Bigeminy/Trigeminy Underlying sinus rhythm with PVC’s regularly

Slide 251: 

Bigeminy

Slide 252: 

Regular Irregularity: Wenckebach Sinus rhythm with progressive prolongation of PR until dropped P wave

Slide 253: 

Wenckebach

Slide 254: 

Irregular Irregularity: Atrial Fibrillation Variable Atrial Flutter MAT Ectopy The “stumbling drunk”

Slide 255: 

Irregular Irregularity: Atrial Fibrillation Irregularly irregular, narrow complex, chaotic baseline

Slide 256: 

Atrial Fibrillation

Slide 257: 

Appears almost regular on this small portion of the strip A look at a larger strip reveals the irregularity

Slide 258: 

Irregular Irregularity: Multifocal Atrial Tachycardia Irregularly irregular, narrow complex, three or more P waves

Slide 259: 

Multifocal Atrial Tachycardia

Slide 260: 

Irregular Irregularity: Ectopy Underlying sinus rhythm disturbed by PAC’s (narrow) or PVC’s (wide)

Slide 261: 

Irregular Irregularity: Atrial Flutter with Variable Block Sawtooth Baseline with Varying Ventricular Response

Slide 262: 

Atrial Flutter with Variable Block

Slide 263: 

Atrial Flutter with Higher Grade Block

Slide 264: 

Regular Sinus Tach PSVT Aflutter with fixed block Narrow complex, very regular and fast

Slide 265: 

Regular Sinus Tach Narrow complex, usually see P waves, defined by >100, Remember 220 – age!

Slide 266: 

Sinus Tach

Slide 267: 

Sinus Tach with LBBB

Slide 268: 

Regular PSVT Narrow complex, often don’t see P waves, typically >150, perhaps over 200

Slide 269: 

Paroxysmal Supraventricular Tachycardia

Slide 271: 

Speaking of Adenosine

Slide 272: 

…but just when we thought life was getting easier…

Slide 273: 

Advanced Cardiac Life Support …is commendable for its continued search for the science of emergency cardiac care …but, misses the boat in terms of telling us how to assess tachycardia in a rememberable manner

Slide 274: 

Remember: If you find a patient with a tachycardia, The first question to ask is “could this be a sinus tachycardia”! Of course, if the patient is on the monitor and you see THIS…..

Slide 275: 

Remember too: 80% of Wide Complex Tachycardias will be VTach The rest will be sinus tach with a bundle branch block

Slide 276: 

Evaluation of Tachycardia Ventricular rate over 100 Max sinus = 220 - age What is the patient’s maximum expected sinus tachycardia? Is it fast? (If so, keep going)

Slide 277: 

If so, rule out and/or treat cause(s), such a hypovolemia, sepis, and other shock states Could it be sinus tachycardia? YES

Slide 278: 

Is it narrow, perfectly regular, and 150 or above? Paroxysmal supraventricular tachycardia, unless sinus tachycardia is possible YES

Slide 279: 

Irregularly irregular, narrow complex, probably atrial fibrillation Also consider frequent ectopy, Variable Aflutter and MAT Is it regular? NO

Slide 280: 

WIDE and PERFECTLY regular, probably Vtach WIDE and irregular, probably atrial fibrillation with bundle branch block Is it wide? YES

Slide 281: 

Narrow OR wide, regular (usually), with sawtooth baseline Atrial flutter (fairly rare) REMEMBER, the block MAY be variable in flutter YES

Slide 282: 

IMPORTANT: Sinus tachycardia with a rate of 150 or above and PAT/PSVT look very similar PAT/PSVT are not usually life threatening except in the rare setting of a patient having myocardial ischemia (chest pain, diaphoresis, or dyspnea)

Slide 283: 

Even More Important: When you can’t tell if a rhythm is sinus tachycardia or PAT/PSVT, be wary of the more serious cause It may be difficult, or even impossible, to see any irregularity in very fast atrial fibrillation

Slide 284: 

Case Studies in Tachycardia Evaluation

Slide 285: 

A 15 year old AA male is found confused, sweaty, with a respiratory rate of 36, a systolic pressure of 80, and this EKG rhythm strip What is the “working impression” and what do you think might be the cause of his problem?

Slide 286: 

72 WF with a cardiac history presents with palpitations and shortness of breath Her systolic is 130 and her lungs have rales

Slide 287: 

72 years old 220 – 72 = 148 The Strip is at about 160 What statement can you make?

Slide 288: 

72 years old 220 – 72 = 148 It HAS to be an arrhythmia! It can’t be sinus tach!

Slide 289: 

30 year old Sweet Sue presents with a systolic of 90 and history of palpitations plus abdominal pain today She ran out of her “heart pill”

Slide 290: 

30 year old female Rate of 180 220 – 30 = 190 What statement can you make?

Slide 291: 

Is it PSVT (hx of palpitations?) or Sinus Tach? Which is more dangerous? 30 year old female Rate of 180 220 – 30 = 190

Slide 292: 

60 year old Aunt Minnie presents with systolic of 90 and no cardiac history She has been ill for two days

Slide 293: 

60 year old with rate of 158 220 – 60 = 160 What statement can you make?

Slide 294: 

60 year old with rate of 158 220 – 60 = 160 Does she need Adenosine?

Slide 295: 

Speaking of Adenosine

Slide 296: 

Summary Thoughts About Tachycardia Don’t be a careless EKG reader Your patients’ lives depend on it Make YOUR medical director proud Remember that you start with the patient’s maximum possible pulse rate (220 – age), eliminate sinus tachycardia if it is too fast or doesn’t look right, and then figure it out from there

Treat the Patient, Not the Monitor!: 

Treat the Patient, Not the Monitor! Remember, all of these findings are relative to the presentation of the patient. BBB, hemiblocks , and axis deviations can be established changes in an individual’s 12 lead. These findings are only significant when they are new onset, or more importantly when they are accompanied by S&S (typical or atypical) of an MI. Treat the patient, not the test! Your patient will often tell you their diagnosis in their own way if you only take the time to listen to them.

Conclusion: 

Conclusion You only see what you look for and you only look for what you know! Systematic approach Understanding of common (and not-so-common) arrhythmias Not all rhythm disorders produce symptoms View the rhythm in the context of the patient’s overall condition: treat the patient, not the tracing!

Slide 300: 

So, Who’s Foolin’ Who??

Slide 301: 

This Talk may be found at www.vdraolectures.blogspot.com vdrao1@rediffmail.com vdrao1@gmail.com www.vdrao.freeforums.com

Slide 302: 

The End