Remove the Mystery from 12 Lead EKG Interpretation for Acute MI The simple, rapid “12 lead solution” to 12 lead confusion! A 12 Lead Program for ALL health care professionals! Copyright Apex Innovations 2003

The Basics….. Let’s do the re-view Coronary Anatomy Conduction Paper and rate basics Rhythm Lead placement Vectors and axis R wave progression

Coronary Anatomy Aorta Circumflex (Cx) Right Coronary Artery (RCA) Left Anterior Decending (LAD)

Constant, Continuous Conduction….the beat goes on Normal P-QRS-T Constant, Continuous Conduction….the beat goes on QRS.. Ventricular depolarization P wave Depolarization & contraction of both atria Iso-electric Line T wave… Ventricular repolarization

Constant, Continuous Conduction….the beat goes on Normal P-QRS-T Constant, Continuous Conduction….the beat goes on R-Upward slope S-Down slope Iso-electric Line Q-First down slope

Normal P-QRS-T P Wave PR Interval QRS Complex ST Segment Represents Atrial depolarization Time between onset of atrial depolarization and onset of ventricular depolarization (AV conduction time) Ventricular depolarization Interval between ventricular depolarization and repolarization Duration < 0.12 seconds 0.12 - 0.20 seconds 0.04 - 0.10 seconds Measure from end of QRS to J-point, the beginning of T wave Height < 2.5 mm Measure start of P wave to start of QRS Q- First negative deflection R- First positive S- Negative deflection after R wave Shape Smooth Prolonged indicates a conduction block Shortened indicates accelerated conduction or junctional in origin In relation to iso-electric line: Depression/Negative indicates ischemia Elevation/Positive indicates injury Orientation Positive in Leads I,II,aVF, V4 Negative in aVR

Cardiac Conduction System Sinus node Internodal pathways AV node Left Bundle Branch Bundle of His Right Bundle Branch Purkinje fibers

Cardiac Conduction System Relationship of ECG to anatomy

Rate: EKG Paper Basics Standard paper speed = 25mm per second Note calibration on side of EKG - 2 Large Blocks tall One small Block = 1mm Voltage One Small Block = .04 Seconds One Large Block = 5mm Voltage One Large Block = .20 Seconds -Increased paper speed makes complexes wider -Decreased paper speed makes the complexes narrower

Rate: Calculation Options RATE = # of R waves in a 6 second strip X 10 RATE = 300  # large squares between R waves RATE Count = Count from a QRS complex on any bold line to the next QRS complex. Count “300, 150, 100, 75, 60, 50” for each bold line after first complex. 300 150 100 75 60 50 Start End Rate = 82 BPM

Rhythms Sinus (SA Node) Normal Sinus Sinus Bradycardia Sinus Tachycardia Sinus Arrhythmia Sick Sinus Syndrome Wandering Atrial Pacemaker Sinus Block Sinus Arrest

Rhythms Continued Atrial Rhythms Premature Atrial Contraction (PAC) Paroxysmal Atrial Tachycardia (PAT) Multifocal Atrial Tachycardia Atrial Flutter Atrial Fibrillation

Rhythms Continued Junctional (AV) Premature Junctional Contraction (PJC) Paroxysmal Junctional Tachycardia (PJT) Junctional Flutter Junctional Fibrillation

Rhythms Continued Ventricular Premature Ventricular Contraction (PVC) - Bigeminy Trigeminy, Quadrageminy Paroxysmal Ventricular Tachycardia (PVT) Multifocal Ventricular Tachycardia Ventricular Flutter Ventricular Fibrillation

Rhythms Continued AV Blocks 1 Prolonged PRI 2 Type I - Wenchebach 2 Type II - Mobitz II - 2:1, 3:1 Conduction 3 Complete Heart Block Bundle Branch - Right BB - Left BB

The 12 Lead EKG… 12 angles or pictures of the electrical activity of the heart 6 Limb Leads 6 Chest or Pre-cordial Leads I II III AVR AVL AVF V1 V2 V3 V4 V5 V6

Looking and Learning: Vectors and Axis ~the hard way~ The sum of all vectors determines the axis A panoramic view of the heart’s electrical activity from 12 different angles

Lead Placement - Lead I, II, III LEAD I Bipolar Limb Lead Looks from Right to Left Shoulder Looks at high lateral wall of left ventricle Supplied by circumflex artery–CX Positive/upright P QRS T - RA + LA LL

Lead Placement - Lead I, II, III LEAD II Bipolar Limb Lead Looks from R Shoulder to Left Leg Looks at inferior wall of left ventricle Supplied by right coronary artery–RCA Positive/upright P QRS T - RA + LA - + LL

Lead Placement - Lead I, II, III LEAD III Bipolar Limb Lead Looks from Left Shoulder to Left Leg Looks at inferior wall of left ventricle Supplied by right coronary artery-RCA A biphasic QRS complex is expected - RA + LA - - + + LL

Augmented Limb Leads AVR AVL Augmented Voltage Left Arm AVF Augmented Voltage Right Arm All complex waves are negative Typically, this lead not used for diagnosing! AVL Augmented Voltage Left Arm Looks at lateral wall of left ventricle Supplied by circumflex artery - CX All complexes should be positive AVF Augmented Voltage (left) Foot Cross between Leads I and II Looks at inferior wall of left ventricle Supplied by right coronary artery-RCA RA LA + + + LL

Lead Placement – V-Leads V1-V2 = Septal V3-V4 = Anterior V5-V6 = Lateral V1-V3 = Posterior V1 – 4th ICS, right of sternum V2 – 4th ICS, left of sternum V3 – Midpoint between V2 and V4 V4 – 5th ICS, mid-clavicular line V5 – Level with V4 , anterior to axillary line V6 – Level with V4, mid-axillary line

V-Lead R Wave Progression The progression or increasing in R wave amplitude from negative to positive in leads V1 to V4 is expected and normal! - V1 - R wave is generally smallest or most negative - V4 - R wave is typically the tallest or most positive - Lack of R wave progression may mean : Pathology- Disease state, CAD, Septal wall MI Normal- A patient with Congenital state, Rotated heart, Obesity, COPD Other- Breast tissue, poor lead placement

R Wave Progression in the V Leads V1 – PQRST All negative V2 – PQRST Should be mostly negative but start progression V3 – PQRST Biphasic with upright T waves V4 – PQRST Nearly completely upright V5 – PQRST Upright V6 – PQRST Upright

Myocardial Infarction Bumps, elevations and tombstones… Ischemia Injury Recognition Criteria Infarct Location Template AMI Evolution Practice EKG’s

Myocardial Infarction Occurs when a coronary artery is narrowed and occludes, terminating the blood and oxygen supply. This results in cardiac hypoxia and irritability which may cause fatal arrhythmias. Without a blood supply to the cardiac muscle, depolarization cannot happen and renders the muscle, electrically dead. An EKG can diagnose AMI location, identify the culprit artery and reveal any blocks in ventricular conduction.

ST Depression = Ischemia Inverted T waves, sometimes peaked T wave deflection is opposite from QRS (Normally T wave is upright when QRS is upright and vice versa) T wave inversion is usually in same leads that demonstrates signs of acute infarction (Q waves, ST elevation)

Causes for ST depression Ischemia Digoxin Toxicity Pulmonary Embolism Ventricular Hypertrophy Left Bundle Branch Block

ST Elevation = Current Injury Depicts current myocardial injury Measure J-point to beginning of ventricular repolarization May be elevated >1mm in limb leads and >2mm in precordial leads Will see reciprocal ST depression in other leads

Causes for ST elevation Pericarditis Ventricular aneurysm Drug induced Myocardial Infarction

Recognition of AMI Know what to look for: ST elevation >1 mm J point Know what to look for: ST elevation >1 mm 3 contiguous leads PR baseline ST-segment deviation = 4.5 mm

AMI  Requires at least 2 of these criteria: History of characteristic chest pain Crushing-pressure in chest, pain radiation to jaw, arms, back, N/V, SOB, diaphoresis Evolutionary EKG changes ST depression (ischemia) ST elevation (injury) Q wave development (muscle death) Elevated cardiac enzymes Troponin, CKMB-CK, Myoglobin

Understanding infarct location Here’s the trick! The 12 Lead Solution to 12 Lead Confusion!

Location, Location, Location! Simple - Rapid!! Finally……. Remove the mystery! Location, Location, Location!

AMI Location Correlation I Lateral aVR V1 Septal V4 Anterior This slide illustrates the 3  4 format of the 12-lead ECG. Each box represents 1 lead, and the viewpoint of that lead is indicated. II Inferior aVL Lateral V2 Septal V5 Lateral III Inferior aVF Inferior V3 Anterior V6 Lateral

Lateral Lead ST Elevation in AMI LEAD I AVL V5 V6  “High Lateral” Wall  Lateral: Usually supplied by Circumflex (CX) Look for reciprocal changes in Lead V1

Normal EKG Lateral Reciprocal Change Lateral Lateral Lateral

Inferior Lead ST Elevation in AMI LEAD II LEAD III AVF Inferior: Usually supplied by Right Coronary Artery (RCA) Look for reciprocal changes in Leads I, AVL

Normal EKG Reciprocal Change Inferior Reciprocal Change Inferior

Septal Lead ST Elevation in AMI Septal: Usually supplied by Left Anterior Descending (LAD) Look for reciprocal changes in Leads V3, AVF

Normal EKG Septal Septal Reciprocal Change Reciprocal Change

Anterior Lead ST Elevation in AMI Usually supplied by Left Anterior Descending (LAD) Look for reciprocal changes in Leads V2, AVF

Normal EKG Anterior Reciprocal Change Reciprocal Change Anterior

12 Lead-Paper Heart To better understand rhythm location: Hold left upper corner and right lower corner of EKG Roll EKG to note: inferior leads at apex lateral leads on sides anterior and septal leads in front

Significant Q Wave Characteristics Height is 1/3 the size of entire QRS complex Width is at least one square or 0.04 seconds in duration Q waves in V1,V2,V3 or V4 indicate anterior or antero- septal infarction Damage from old infarcts cause Q waves that last a lifetime Abnormal if thick on tracing Q wave may be normal in AVR

ST segment Evolution and Q wave development with AMI

Differentiating Between Acute and Old MI Q wave with no other morphology = old MI Q wave and ST segment elevation (with or without T wave inversion) = AMI Q wave and inverted T wave = age undetermined

Evolutional Changes of an Acute Myocardial Infarction

Identify infarct location using a systematic approach Rhythm ST Depression ST Elevation R Wave Progression Q Waves

Let’s take a look at… the Good, the Bad and the Ugly! ~EKG Review~

Review #1 What Does This 12-Lead ECG Show? INFERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Review #2 What Does This 12-Lead ECG Show? LATERAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Review #3 What Does This 12-Lead ECG Show? LATERAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Appearances and History are Important! Your patient, a 58 y/o male, was diagnosed with cancer 2 weeks ago and was scheduled to receive his first chemotherapy treatment this morning. Instead, he was delivered in a wheelchair hurriedly (by his oncologist), to the emergency department in distress. He presents complaining of intense chest pain described as a “10”, is very restless, nauseated, diaphoretic and pale. You order the usual cardiac work-up. Here is what his EKG showed…

Review #4 What Does This 12-Lead ECG Show? LATERAL SEPTAL ANTERIOR INFERIOR

Later that day… This patient’s cardiac workup returned within normal limits and was diagnosed with anxiety and released to begin his chemotherapy.

Review #5 What Does This 12-Lead ECG Show? LATERAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Review #6 What Does This 12-Lead ECG Show? INFERIOR LATERAL LATERAL SEPTAL ANTERIOR INFERIOR

Review #7 What Does This 12-Lead ECG Show? LATERAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Appearances and History are Important! Your patient, a 62 year old male pharmacist, presents at 6:00AM with chest pressure radiating to his neck, jaw and left arm. He is mildly short of breath and says he’s had indigestion all night. You order the usual cardiac work-up. Here is what his EKG showed…

Review #8 What Does This 12-Lead ECG Show? LATERAL SEPTAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Later that day… The Inferolateral/Anteroseptal MI caused massive injury and tissue death, and the patient subsequently died.

Review #9 What Does This 12-Lead ECG Show? INFERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Review #10 What Does This 12-Lead ECG Show? SEPTAL LATERAL SEPTAL ANTERIOR INFERIOR

Posterior MI’s can be tricky! EKG changes are seen in V1-V3 (the anterior precordial leads) and are a mirror image of an anteroseptal MI You will see: Increased R wave amplitude and duration R wave is more prominent than S wave in V1 and V2 ST depression and large inverted T waves V1-V3 Posterior MI HINT: R waves in V1 and V2? Suspect Posterior MI!

Review #11 What Does This 12-Lead ECG Show? POSTERIOR LATERAL SEPTAL? ANTERIOR INFERIOR ANTERIOR?

Review #12 What Does This 12-Lead ECG Show? Look at those R waves!!! POSTERIOR INFERIOR LATERAL SEPTAL? ANTERIOR INFERIOR ANTERIOR?

Tick-Tock ~~ Time is Muscle! ~~

Please stop here! ~Test Time~ Answer the Self Assessment Sheet’s first 8 questions. 2. Next proceed to the remaining slides and record the infarct location for each EKG on the self assessment.

Quiz #1 Where is the elevation or infarct? LATERAL SEPTAL ANTERIOR INFERIOR INFERIOR

Quiz #2 Where is the elevation or infarct? SEPTAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Quiz #3 Where is the elevation or infarct? LATERAL LATERAL SEPTAL ANTERIOR INFERIOR

Quiz #4 Where is the elevation or infarct? SEPTAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR Review the 12-lead ECG. Go lead by lead, and pick one good complex in each lead. Find the J point and ST segment. Compare the ST to the TP segment, looking for 1 mm (1 small box) of elevation (ignore ST depression for now). Place a check mark next to any lead with 1 mm of ST-segment elevation. Localize the area of infarction.

Quiz #5 Where is the elevation or infarct? LATERAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Quiz #6 Where is the elevation or infarct? SEPTAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Quiz #7 Where is the elevation or infarct? INFERIOR LATERAL LATERAL SEPTAL ANTERIOR INFERIOR

Quiz #8 Where is the elevation or infarct? LATERAL SEPTAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Quiz #9 Where is the elevation or infarct? SEPTAL LATERAL SEPTAL ANTERIOR INFERIOR

Quiz #10 Where is the elevation or infarct? LATERAL ANTERIOR INFERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Quiz #11 Where is the elevation or infarct? SEPTAL ANTERIOR LATERAL SEPTAL ANTERIOR INFERIOR

Thank you for your participation! Please complete the program and speaker evaluation. Copyright Apex Innovations 2003