Shannon McCarter PGY2 FM Civic Approach to the ECG.

Shannon McCarterShannon McCarter

PGY2 FM CivicPGY2 FM Civic

Approach to the ECGApproach to the ECG

99 Topics99 Topics

General Approach to ECGGeneral Approach to ECG

1.1. RateRate

2.2. RhythmRhythm

3.3. AxisAxis

4.4. RotationRotation

5.5. Waves, Segments, IntervalsWaves, Segments, Intervals

6.6. HypertrophyHypertrophy

1. RATE1. RATE

Regular rhythms:Regular rhythms:– 300/# large square between R-R300/# large square between R-R– 1500/# small squares between R-R1500/# small squares between R-R– Countdown sequence 300-150-100-75-60 -Countdown sequence 300-150-100-75-60 -

5050 Irregular rhythms:Irregular rhythms:

– # of complexes on ECG (10seconds) x 6# of complexes on ECG (10seconds) x 6

Paper speed: 25mm/sec

2. Rhythm2. Rhythm

Step 1: Is the QRS regular or irregularStep 1: Is the QRS regular or irregular– ?regularly irregular or irregularly

irregular Step 2: Assess the QRSStep 2: Assess the QRS

?wide or narrow complex?wide or narrow complex Step 3: P waves present?Step 3: P waves present? Step 4: Relationship of P wave with QRSStep 4: Relationship of P wave with QRS

3. Axis3. Axis Look at Lead I and AVF (other Look at Lead I and AVF (other

methods involve Lead II)methods involve Lead II)Lead I AVF Axis

+ + Normal (-30 to 90)

+ - Possible LAD

- + RAD

- - Extreme axis deviation

3. Axis3. Axis

Another method:Another method:– Examine isoelectric limb lead Examine isoelectric limb lead – Most of electrical current moving Most of electrical current moving

perpendicular to isoelectric leadperpendicular to isoelectric lead

Lead GroupingLead Grouping

II, III, AVF – inferior leadsII, III, AVF – inferior leads V1, V2 – antero-septal leadsV1, V2 – antero-septal leads V3, V4 – anterior leadsV3, V4 – anterior leads V5,V6, I, aVL – lateral leadsV5,V6, I, aVL – lateral leads

4. Rotation4. Rotation

Looking at the heart in the transverse Looking at the heart in the transverse axisaxis

General rule:General rule:– Heart rotates to hypertrophy and away Heart rotates to hypertrophy and away

from infarctfrom infarct Clockwise rotation: isoelectric QRS in Clockwise rotation: isoelectric QRS in

V5, V6V5, V6 Counter-clockwise: isoelectric in V1, V2Counter-clockwise: isoelectric in V1, V2

5.Waves, Intervals, and 5.Waves, Intervals, and SegmentsSegments

PR interval: PR interval: – 0.12-0.20 seconds0.12-0.20 seconds

QRS complex:QRS complex:– 0.06-0.11 seconds0.06-0.11 seconds

QT intervalQT interval– N < 440msec men,<460 womenN < 440msec men,<460 women– Varies with HR. In General should be <1/2R-RVaries with HR. In General should be <1/2R-R– Ventricular depolarization + repolarizationVentricular depolarization + repolarization

Waves: assess morphology, voltage (P, Q, R, S, T)Waves: assess morphology, voltage (P, Q, R, S, T) Segments assess for elevation or depression (PR, Segments assess for elevation or depression (PR,

ST)ST)

6. Hypertrophy6. Hypertrophy

Left Ventricular HypertrophyLeft Ventricular Hypertrophy S wave of V1/ V2 + R wave of V5/V6 > S wave of V1/ V2 + R wave of V5/V6 >

35mm35mm R wave in aVL >11 mmR wave in aVL >11 mm May also see LAE and LADMay also see LAE and LAD

Right Ventricular HypertrophyRight Ventricular Hypertrophy RAD +/- RAERAD +/- RAE R wave in V1 > 7mm or R/S ratio >1R wave in V1 > 7mm or R/S ratio >1

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This rhythm is the most common This rhythm is the most common sustained arrhythmia. sustained arrhythmia.

What is atrial fibrillation?What is atrial fibrillation?

Atrial fibrillationAtrial fibrillation Most common sustained arrhythmiaMost common sustained arrhythmia

Complications: cardiomyopathy, embolic events, CHFComplications: cardiomyopathy, embolic events, CHF

Etiology: HTN, IHD, Valvular heart disease, infection, Etiology: HTN, IHD, Valvular heart disease, infection, electrolytes (hypoK, hypoMg), pulmonary (PE), electrolytes (hypoK, hypoMg), pulmonary (PE), pericardial disease, drugs, endocrine (thyrotoxicosis, pericardial disease, drugs, endocrine (thyrotoxicosis, pheo), acid-base disturbance, cardiomyopathies, pre-pheo), acid-base disturbance, cardiomyopathies, pre-excitation syndromesexcitation syndromes

ECG: irregularly irregular rhythm, no P waves, QRS ECG: irregularly irregular rhythm, no P waves, QRS normally < 120msecnormally < 120msec

Atrial FibrillationAtrial Fibrillation Classification: first episode, recurrent (>2), paroxysmal Classification: first episode, recurrent (>2), paroxysmal

(< 7 days), persistent (>7 days), permanent (> 1 year)(< 7 days), persistent (>7 days), permanent (> 1 year)

Management:Management:– Anti-coagulant: CHADS2Anti-coagulant: CHADS2– Rate controlRate control– Rhythm ControlRhythm Control– CardioversionCardioversion– **Treat underlying****Treat underlying**

See Canadian Cardiovascular Guidelines for See Canadian Cardiovascular Guidelines for Management of Atrial Fibrillation (2014)Management of Atrial Fibrillation (2014)

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This supraventricular tachycardia has a This supraventricular tachycardia has a characteristic saw-tooth pattern. characteristic saw-tooth pattern.

What is atrial flutter?What is atrial flutter?

Atrial FlutterAtrial Flutter Rate approximately 300bpmRate approximately 300bpm

Etiology: re-entrant circuitEtiology: re-entrant circuit

Look for conduction 2:1, 3:1, 4:1Look for conduction 2:1, 3:1, 4:1

Saw tooth waves best seen in inferior leadsSaw tooth waves best seen in inferior leads

Mngt: Mngt: – AblationAblation– Similar management to atrial fibrillationSimilar management to atrial fibrillation

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Unless ACLS and shock is rapidly instituted, this rhythm is invariably fatal

What is Ventricular fibrillation?What is Ventricular fibrillation?

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This mnemonic is instrumental in ACLS This mnemonic is instrumental in ACLS and helpful for remembering the causes of and helpful for remembering the causes of cardiac arrest.cardiac arrest.

What is 5 H’s and 5 T’s?What is 5 H’s and 5 T’s?

5 H’s and 5 T’s5 H’s and 5 T’s– 5 H’s:5 H’s:

HypoxiaHypoxia HypovolemiaHypovolemia HyperK+HyperK+ Hydrogen ionHydrogen ion HypothermiaHypothermia

– 5 T’s:5 T’s: Tension pneumothoraxTension pneumothorax TamponadeTamponade ToxinsToxins Thrombosis – heartThrombosis – heart Thrombosis - lungThrombosis - lung

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This heart block often is benign and does This heart block often is benign and does not require treatment.not require treatment.

What is: AV block: 2What is: AV block: 2ndnd degree, Mobitz Type degree, Mobitz Type I I – Aka Wenckebach Aka Wenckebach

Heart BlocksHeart Blocks 11stst degree: PR > 200ms degree: PR > 200ms

– Usually benign. No treatment required.Usually benign. No treatment required. 22ndnd degree degree

– Mobitz I (Wenckebach): progressive PR prolongation Mobitz I (Wenckebach): progressive PR prolongation until QRS droppeduntil QRS dropped Rarely progresses to Type II, CHBRarely progresses to Type II, CHB Rx: asymptomatic do not require rx. Rx: asymptomatic do not require rx. Usually responds to atropineUsually responds to atropine

– Mobitz II: PR interval stable with occasional dropped QRSMobitz II: PR interval stable with occasional dropped QRS High risk of syncope or CHBHigh risk of syncope or CHB Requires temp pacing/ permanent pacemakerRequires temp pacing/ permanent pacemaker

Etiology: high vagal tone, age related, infectious, infarct, Etiology: high vagal tone, age related, infectious, infarct, drugs, electrolyte abN, post-cardiac surgerydrugs, electrolyte abN, post-cardiac surgery

Heart BlocksHeart Blocks 33rdrd degree – Complete Heart Block degree – Complete Heart Block

– Complete AV dissociation Complete AV dissociation – P waves not conductedP waves not conducted– Etiology: inferior MI, progression of Etiology: inferior MI, progression of

Mobitz Type I/ II, AV nodal blockersMobitz Type I/ II, AV nodal blockers– Require temporary pacing and Require temporary pacing and

permanent pacemakerpermanent pacemaker

2 - $2002 - $200 What drugs should you avoid with a patient What drugs should you avoid with a patient

with this condition?with this condition?

What are AV blockers?What are AV blockers?

Pre-excitation syndrome: Pre-excitation syndrome: WPWWPW

• Congenital accessory pathway (Bundle of Kent)• Can cause AVRT (atrioventricular reentry tachycardia)• ECG findings: PR < 120msec, delta wave,

prolongation QRS, ST segment and T wave discordant changes (opposite direction of QRS complex)

• Treatment with AV nodal blockers VT or VF• Unstable: cardioversion• Stable: procainamide

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This syndrome is caused by a sodium This syndrome is caused by a sodium channelopathy. channelopathy.

What is Brugada?What is Brugada?

BrugadaBrugada

Brugada SyndromeBrugada Syndrome• Epidemiology: often Asian males, middle age• ECG changes can be transient and unmasked by fever,

drugs, ischemia, hypothermia, hypoK• Diagnosis requires: ECG changes + 1 clinical criteria

• ECG: Type I: Brugada sign: coved ST segments >2mm in >1 of V1-V3 followed by negative T wave• Type II: nondx - > 2mm of saddleback ST

elevation in V1-V3• Clinical criteria: family history of SD < 45, Vfib/

polymorphic VT, Coved ECG changes in family, syncope, inducible VT with electrical stimulation, nocturnal agonal respirations

• Management: ICD• No treatment SD age 40s

2 - $4002 - $400 What is the name of this condition? What is the name of this condition? Bonus marks: what is the clinical significanceBonus marks: what is the clinical significance

What is Wellen’s Syndrome? It indicates What is Wellen’s Syndrome? It indicates critical stenosis of the LAD.critical stenosis of the LAD.

Wellen’s SyndromeWellen’s Syndrome Deep, symmetric or biphasic T wave inversion Deep, symmetric or biphasic T wave inversion

in anterior precordial leads (V2, V3)in anterior precordial leads (V2, V3) Indicates significant proximal LAD stenosisIndicates significant proximal LAD stenosis Patients may be pain free initially but at high Patients may be pain free initially but at high

risk of extensive anterior wall infarct in the risk of extensive anterior wall infarct in the upcoming days/weeksupcoming days/weeks

No ST segment changes. No Q waves.No ST segment changes. No Q waves. Pathophysiology: sudden occlusion of LAD Pathophysiology: sudden occlusion of LAD

transient anterior STEMI transient anterior STEMI reperfusion reperfusion biphasic T waves biphasic T waves deep inverted T waves deep inverted T waves

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This condition produces a characteristic chest This condition produces a characteristic chest pain that is pleuritic in nature, worse with pain that is pleuritic in nature, worse with lying flat, relieved with sitting forward and lying flat, relieved with sitting forward and often is associated with a viral infection. often is associated with a viral infection.

What is pericarditis?What is pericarditis?

PericarditisPericarditis ECG changes:ECG changes:

– Diffuse concave ST segment elevationDiffuse concave ST segment elevation– Diffuse PR depressionDiffuse PR depression– Sinus tachycardiaSinus tachycardia– Reciprocal changes in AVRReciprocal changes in AVR– ProgressesProgresses N ST segments + flat T waves N ST segments + flat T waves T waves inverted T waves inverted

(3+ weeks) (3+ weeks) ECG normal ECG normal Etiology: infectious (viral –coxsackie), immunological Etiology: infectious (viral –coxsackie), immunological

(SLE), uremia, post-MI, trauma, post-cardiac surgery, (SLE), uremia, post-MI, trauma, post-cardiac surgery, drug related, post radiotherapy, paraneoplastic drug related, post radiotherapy, paraneoplastic syndromessyndromes

Management: treat underlyingManagement: treat underlying– NSAID + colchicine NSAID + colchicine – Glucocorticoids if refractory, autoimmune, connective tissue d/o, Glucocorticoids if refractory, autoimmune, connective tissue d/o,

uremia not responding to dialysis, contraindications to NSAIDsuremia not responding to dialysis, contraindications to NSAIDs– If associated effusion +/- drainageIf associated effusion +/- drainage

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This ECG belong to an individual with retro This ECG belong to an individual with retro sternal chest pressure, SOB and a history of sternal chest pressure, SOB and a history of smoking.smoking.

What is anterior STEMI?What is anterior STEMI?

3 - $3003 - $300 These drugs should be used with caution These drugs should be used with caution

in patients presenting with inferior STEMI. in patients presenting with inferior STEMI.

What is drugs that affect preload e.g. nitrates, morphine?What is drugs that affect preload e.g. nitrates, morphine?

Inferior STEMIInferior STEMI

More favorable prognosis than anterior STEMIsMore favorable prognosis than anterior STEMIs 40% have right ventricular infarction 40% have right ventricular infarction GET GET

right sided leadsright sided leads– Concern about posterior STEMI in ALL inferior and Concern about posterior STEMI in ALL inferior and

lateral STEMIs lateral STEMIs OBTAIN 15 lead ECG OBTAIN 15 lead ECG 20% associated with bradyarrhythymias 20% associated with bradyarrhythymias Most common etiology RCA (80%), left Most common etiology RCA (80%), left

circumflex (20%)circumflex (20%) ECG: ST elevation in II, III and AVF, reciprocal ECG: ST elevation in II, III and AVF, reciprocal

changes in aVLchanges in aVL

DO NOT MISS!DO NOT MISS!

ST elevation in aVR with diffuse ST ST elevation in aVR with diffuse ST depression indicates left main disease, depression indicates left main disease, triple vessel disease or proximal LAD triple vessel disease or proximal LAD occlusionocclusion

STEMI ManagementSTEMI Management ABCs, cardiac monitoringABCs, cardiac monitoring Oxygen if O2 sats < 90%Oxygen if O2 sats < 90% ReperfusionReperfusion

– PCI: <90 minutesPCI: <90 minutes– FibrinolyticsFibrinolytics

Anti-platelet:Anti-platelet:– ASA ASA – Clopidogrel (if fibrinolytic candidate)Clopidogrel (if fibrinolytic candidate)– Ticagrelor (if PCI)Ticagrelor (if PCI)

Anti-coagulant: HeparinAnti-coagulant: Heparin Nitrates: 3 SL then IV. Caution if preload dependentNitrates: 3 SL then IV. Caution if preload dependent Morphine: caution as can increase mortalityMorphine: caution as can increase mortality B-blockers: caution in heart failure, low CO, high risk of B-blockers: caution in heart failure, low CO, high risk of

cardiogenic shock, bradycardia, reactive airway diseasecardiogenic shock, bradycardia, reactive airway disease Statins: as early as possibleStatins: as early as possible

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These criteria are useful in differentiating These criteria are useful in differentiating a LBBB from an acute myocardial a LBBB from an acute myocardial infarction.infarction.

What are the sgarbossa criteria?What are the sgarbossa criteria?

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This is the textbook ECG finding for This is the textbook ECG finding for pulmonary embolism even though the pulmonary embolism even though the most common finding is sinus tachycardia.most common finding is sinus tachycardia.

What is S1, Q3, T3 pattern?What is S1, Q3, T3 pattern?

Pulmonary embolismPulmonary embolism Findings on ECG not sensitive, non-specificFindings on ECG not sensitive, non-specific DDX: any cause of acute/chronic cor pulmonale:DDX: any cause of acute/chronic cor pulmonale:

– Acute: pneumonia, COPDAE, pneumothorax, recent Acute: pneumonia, COPDAE, pneumothorax, recent pneumonectomypneumonectomy

– Chronic: COPD, CF, ILD, OSA, recurrent small PEsChronic: COPD, CF, ILD, OSA, recurrent small PEs ECG findings:ECG findings:

– #1 sinus tachycardia#1 sinus tachycardia– RBBBRBBB– Right ventricular strain pattern, RADRight ventricular strain pattern, RAD– Right atrial enlargementRight atrial enlargement– S1Q3T3S1Q3T3– T wave inversions in inferior leadsT wave inversions in inferior leads

4 - $2004 - $200 The phenomenon of electrical alternans The phenomenon of electrical alternans

produced by the heart swinging (QRS height produced by the heart swinging (QRS height varies from beat to beat) and low voltage on varies from beat to beat) and low voltage on an ECG can be indicative of this condition an ECG can be indicative of this condition that may require a tap? that may require a tap?

What is severe pericardial effusion and What is severe pericardial effusion and cardiac tamponade?cardiac tamponade?

4 - $3004 - $300 A patient presents with the following rhythm A patient presents with the following rhythm

strip to the ED after being prescribed strip to the ED after being prescribed levofloxacin. Translated this conditions means levofloxacin. Translated this conditions means twisting of the spikes. twisting of the spikes.

What is Torsades de pointes? (Secondary to What is Torsades de pointes? (Secondary to Prolonged QT)Prolonged QT)

Prolonged QTProlonged QT Symptoms:Symptoms:

– Most episodes revert spontaneously to sinus rhythmMost episodes revert spontaneously to sinus rhythm– Palpitations, dizziness, syncope, sudden cardiac deathPalpitations, dizziness, syncope, sudden cardiac death

Pathophysiology: prolonged repolarization gives rise to early after Pathophysiology: prolonged repolarization gives rise to early after depolarizations depolarizations PVCs PVCs If PVC occurs in preceding T wave = R If PVC occurs in preceding T wave = R on T phenomenon on T phenomenon Torsade's de Pointes Torsade's de Pointes VF VF

Etiology:Etiology:– Drugs: anti-psychotics, tramadol, abx, type I anti-arrhythmicDrugs: anti-psychotics, tramadol, abx, type I anti-arrhythmic– Metabolic (low Mg, Low K, low Ca)Metabolic (low Mg, Low K, low Ca)– Congenital prolonged QT syndromesCongenital prolonged QT syndromes– Increased ICPIncreased ICP

Management:Management:– Treat underlying + stop offending agentTreat underlying + stop offending agent– Replace electrolytesReplace electrolytes– MgS04 +/- antiarrhythmic drugsMgS04 +/- antiarrhythmic drugs– Overdrive pacing, defibrillation Overdrive pacing, defibrillation

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What is fusion beat?What is fusion beat?

This ECG demonstrates a common pattern that is useful for DDX VT versus SVT with aberrancy.

VT versus SVT with VT versus SVT with aberrancy aberrancy

– Features that suggest VTFeatures that suggest VT Absence of RBBB/LBBBAbsence of RBBB/LBBB Extreme axis deviationExtreme axis deviation Broad complexes >160msBroad complexes >160ms Capture beats Capture beats Fusion beatsFusion beats RSR’ complex with taller left rabbit earRSR’ complex with taller left rabbit ear AV dissociationAV dissociation

– Clinical history that increases likelihood of VTClinical history that increases likelihood of VT Age >35Age >35 Structural heart diseaseStructural heart disease IHDIHD Previous MIPrevious MI CHFCHF Family history of sudden deathFamily history of sudden death

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This medication can be used as an This medication can be used as an antidote to treat most beta-blocker antidote to treat most beta-blocker overdoses.overdoses.

What is glucagon *?What is glucagon *?

Beta-Blocker OverdoseBeta-Blocker Overdose

**Propranolol causes sodium channel blockage**Propranolol causes sodium channel blockage QRS QRS widens widens Give NaHCO3 Give NaHCO3

**Sotalol causes K efflux blockage **Sotalol causes K efflux blockage Long QT Long QT TdP TdP S/S: heart failure, bronchospasm, hyperK, hypoglycemia, S/S: heart failure, bronchospasm, hyperK, hypoglycemia,

coma, seizurecoma, seizure ECG findings: bradycardia, heart block, ECG findings: bradycardia, heart block, Management:Management:

– Fluid, B-agonists, VasopressorsFluid, B-agonists, Vasopressors– Atropine, PacingAtropine, Pacing– Antidotes: Antidotes:

GlucagonGlucagon High dose insulinHigh dose insulin Intralipid if refractoryIntralipid if refractory

5 - $3005 - $300 This ECG strip has a characteristic T wave This ECG strip has a characteristic T wave

pattern of an acute metabolic disturbance. pattern of an acute metabolic disturbance. Bonus: What are the treatment options?Bonus: What are the treatment options?

What is treatment of hyperkalemia?What is treatment of hyperkalemia?

HyperkalemiaHyperkalemia Pathophysiology: high K+ > 5.5 levels decrease myocardial excitability Pathophysiology: high K+ > 5.5 levels decrease myocardial excitability Etiology: Etiology:

– renal failure, dialysis, renal failure, dialysis, – Drugs: ACEI, K sparing diuretics, K+ supplements, NSAIDS, digoxin Drugs: ACEI, K sparing diuretics, K+ supplements, NSAIDS, digoxin

toxicity, succinylcholine toxicity, succinylcholine – Release from cells (Rhabdo, burns, hemolysis, shifts – acidosis/low Release from cells (Rhabdo, burns, hemolysis, shifts – acidosis/low

insulin/b-blockersinsulin/b-blockers ECG findings: peaked T waves (symmetrical), ECG findings: peaked T waves (symmetrical),

– P wave widens, PR segment lengthens P wave widens, PR segment lengthens P waves eventually P waves eventually disappeardisappear

– QRS prolonged, sinus bradycardia, conduction blocksQRS prolonged, sinus bradycardia, conduction blocks– Sine wave (LATE)Sine wave (LATE)

Treatment:Treatment:– Calcium gluconate Calcium gluconate – Temporary MeasuresTemporary Measures

Insulin, SalbutamolInsulin, Salbutamol– EliminationElimination

Hemodialysis, Kayexalate, Loop diureticsHemodialysis, Kayexalate, Loop diuretics

Final JeopardyFinal Jeopardy This traditional Newfoundland musical This traditional Newfoundland musical

instrument (featured in the picture) is fashioned instrument (featured in the picture) is fashioned out of household and toolshed items. out of household and toolshed items.

What is the ugly stick?What is the ugly stick?