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Emergency Medicine Andrew Petrosoniak, MD PGY2 Emergency Medicine University of Toronto Canada Tachyarrhythmias & Cardioversion

Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

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Page 1: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Andrew Petrosoniak, MDPGY2 Emergency Medicine

University of TorontoCanada

Tachyarrhythmias & Cardioversion

Page 2: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Objectives1. (Very) Briefly review pathophysiology

of arrhythymias (4 slides!)2. Cardioversion3. Tachydysrhythmias4. Special case of wide complex

tachyardia5. Example ECGs

Page 3: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Cardiac conduction system

Page 4: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Action Potentials

Page 5: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Tachyarrhythmias: mechanisms1. Automaticity

– Increase/decrease rate of spontaneous depolarization of cells above their threshold

2. Re-entry– Impulse traveling in a circular movement

3. Triggered

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Emergency Medicine

Re-entry mechanism

Necessary Conditions1.Two paths2.One path must be slower3.Critical timing

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Emergency Medicine

Now, the patient!• IV, oxygen, monitor & defibrillator to

bedside• Rhythm strip • If possible obtain ECG• Ask yourself 4 questions every time

Page 8: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Questions to ask when analyzing an ECG 1. Is the patient stable or unstable?2. Is the QRS narrow or wide?3. Is the rate regular or irregular?4. Are P waves visible?

Page 9: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Questions to ask when analyzing an ECG 1. Is the patient stable or unstable?2. Is the QRS narrow or wide?3. Is the rate regular or irregular?4. Are P waves visible?

Page 10: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

1. Hypotension2. Chest pain (suggestive of

ischemia)3. Shortness of breath4. Decreased level of

consciousness

Stable vs. Unstable

Page 11: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

UNSTABLE = SYNCHRONIZED CARDIOVERSION

Page 12: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Electrical Cardioversion • Electrical shock to heart (synchronized to QRS

complex)• Cardiac cells depolarize and restarts electrical

cardiac activity• SA node resumes pacemaker activity • Avoid shock during relative refractory period (may

cause VF)• Effective if etiology of arrhythmia is reentry circuit • Not effective if impulse originates from SA node

Page 13: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Electrical Cardioversion• Synchronization = Prevent R on T phenomenon• Press “Sync” on the machine• Be familiar with your machine; do you need to press

sync after each shock?

Page 14: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

• Insufficient evidence to suggest either position is superior for effective cardioversion (AP vs. AL) Emerg Med J 2005 22(1):44-6

• Reasonable to try alternative position if unsuccessful with initial attempts Interact Cardiovasc Thorac Surg 2004 3:386-89

Electrical Cardioversion

FRONT BACKBotto G L et al. Heart 1999;82:726-730

Page 15: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Narrow Complex QRS

Narrow Complex QRS

Wide Complex QRS

Wide Complex QRS

Irregular

Irregular

Regular

Regular

Regular

Regular

Polymorphic VT

Polymorphic VT

(Am J Emerg Med 2010;28:159-165, AHA 2010 guidelines)

Electrical Cardioversion

100 - 150J100 - 150J50J50J 100J100J 200J200J

**Double energy dose if unsuccessful

Unsynchronized

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Emergency Medicine

Recap

• Re-entry mechanism: most common tachydysrhythmia

• Every ECG = 4 Questions • Unstable = synchronized

cardioversion• Atrial fibrillation requires most energy

(>100J)

Page 17: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Questions to ask when analyzing an ECG 1. Is the patient stable or unstable?2. Is the QRS narrow or wide?3. Is the rate regular or irregular?4. Are P waves visible?

Page 18: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Narrow Complex

Tachycardia

Narrow Complex

Tachycardia

Hemodynamically

Unstable

Hemodynamically

Unstable

Hemodynamically

Stable

Hemodynamically

Stable

IrregularIrregularRegularRegular

Synchronized cardioversionSynchronized cardioversion

Approach to narrow complex tachycardias

Page 19: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Narrow complex tachycardiasREGULAR IRREGULAR

• Sinus Tachycardia

• Paroxysmal supraventricular tachycardia (PSVT)

• Atrial flutter with consistent conduction

• Atrial Fibrillation

• Atrial flutter with variable conduction

• Multifocal atrial tachycardia

Page 20: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Case: 24 year old, healthy male Chief complaint: 1 hour of palpitations • No chest pain or shortness of breath• HR 180, BP 145/85, RR 18, 98% (room air)

Page 21: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

REGULAR • Sinus Tachycardia

• Paroxysmal supraventricular tachycardia (PSVT)

• Atrial flutter with consistent block

Narrow complex tachycardias

Page 22: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Case: 24 year old, healthy male Palpitations, stable hemodynamicallyECG: regular, narrow complex tachycardia

What are the management options?

Page 23: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Regular narrow complex tachycardia

Modified from Neumar et al. Circulation 2010; 122;S729-S767

Page 24: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Case: 24 year old, healthy male ECG: regular, narrow complex tachycardia

• Management is initiated• What does this rhythm strip demonstrate?

Page 25: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

62 M with palpitations and dyspneaPMHx: CHF, HTN

Page 26: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

REGULAR • Sinus Tachycardia

• Paroxysmal supraventricular tachycardia (PSVT)

• Atrial flutter with consistent block

Narrow complex tachycardias

Page 27: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Atrial Flutter: Management• ACLS: classify unstable vs. stable

– Stable: rate control and only consider cardioversion if <48hrs

– Rate control (no CHF): IV metoprolol or IV diltiazem

– Rate control (with CHF): digoxin or amiodarone – Electrical Cardioversion if unstable

• Electrical cardioversion may be preferred method yet electrical dose is unclear (Ann Emerg Med 2011 Jan 21 Epub ahead of print)

Page 28: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

62 M with palpitations and dyspneaPMHx: CHF, HTN

Management• Further history: 7 days of palpitations• In ED, BP 130/65 P 150 98%1L NP• Decision to rate control and arrange follow-up

Page 29: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Case: 68 yr old female1 day of palpitations, slight chest discomfort PMHx: NSTEMI 10 yrs ago, high cholesterol, hypertension

Vitals: 150-170bpm, BP 108/45, 95% 1L NP, RR 20

Page 30: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

IRREGULAR • Atrial fibrillation

• Atrial flutter with variable block

• Multi focal atrial tachycardia

Narrow complex tachycardias

Page 31: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Questions to ask when analyzing an ECG 1. Is the patient stable or unstable?

A. HypotensionB. Chest painC. Shortness of breathD. Decreased LOC

2. Is the QRS narrow or wide?3. Is the rate regular or irregular?4. Are P waves visible?

Page 32: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Management of Atrial Fibrillation in the ED

• Lack of strong evidence to guide ED management

• Decision to cardiovert new onset A. Fib, varies significantly between institutions: 42-82% at 8 Canadian EDs (Ann Emerg Med 2011 57(1):13-21)

• AFFIRM & AF-CHF only apply to outpatient population but suggests no difference between rate vs. rhythm control

• Significant controversy exists between rate vs. rhythm control in acute AF

Page 33: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

New Onset Atrial

Fibrillation

New Onset Atrial

Fibrillation

Hemodynamically

Unstable

Hemodynamically

Unstable

Hemodynamically

Stable

Hemodynamically

StableRate Control

IV metoprolol or diltiazem

Rate ControlIV metoprolol or

diltiazem

> 48hrs> 48hrs<48hrs <48hrs

Anti-arrhythmics +/- electric

cardioversion

Anti-arrhythmics +/- electric

cardioversion

TEE or 3wks anti-coagulation then cardioversion

TEE or 3wks anti-coagulation then cardioversion

Chest 2009; 135:849-859

Synchronized cardioversionSynchronized cardioversion

Page 34: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Rate controlNo accessory pathway• Diltiazem IV 0.25mg/kg over 2min (Class I)

• Verapamil IV 0.075-0.15mg/kg over 2min (Class I)

Accessory Pathway• Amiodarone IV 150mg over 10min (Class IIa)

Heart Failure without accessory pathway• Digoxin IV 0.25mg q2h (Class I)

• Amiodarone IV 150mg over 10min (Class IIa)

ACC/AHA/ESC 2006 Atrial Fibrillation guidelines

Page 35: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Rhythm control: Stable patients• Consider cardioversion especially if younger, without

hypertension or heart disease ACC/AHA/ESC Atrial Fibrillation guidelines 2006

• Ottawa protocol: IV 1g procainamide (in 250ml D5W) over 1hr; 58% conversion rate CJEM 2010 12(3):181-91

• Amiodarone 3-5mg/kg IV over 15-20min • Ibutilide 0.015-0.02mg/kg IV over 10-15min

• Electrical cardioversion: 80-90% conversion rates

• Admit AF patients if: – Unstable, MI, worse heart failure

Page 36: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

BACK TO THE CASE

Case: 68 yr old female1 day of palpitations, slight chest discomfort Vitals: 150-170bpm, BP 108/45, 95% 1L NP, RR 20

MANAGEMENT• if patient becomes unstable then synchronized cardioversion• Probably reasonable to rate control • Decide whether chemical or electrical cardioversion is appropriate

Page 37: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

RecapNarrow complex tachycardias

• Unstable vs. stable• Synchronized cardioversion if unstable• If stable Adenosine first if stable• Rate control especially if unknown duration• Chemical cardioversion: consider amiodarone or

procainamide• Electricity more effective than medication

Page 38: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Wide complex tachycardias

Page 39: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Approach to wide complex tachycardias

Wide Complex Tachycardia

Wide Complex Tachycardia

Hemodynamically

Unstable

Hemodynamically

Unstable

Hemodynamically

Stable

Hemodynamically

Stable

IrregularIrregularRegularRegular

Synchronized cardioversionSynchronized cardioversion

Page 40: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

1. Hypotension2. Chest pain (suggestive of

ischemia)3. Shortness of breath4. Decreased level of

consciousness

Wide Complex TachycardiaStable vs. Unstable

Unstable = Immediate Synchronized Cardioversion

Page 41: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Regular• Monomorphic VT

• SVT with aberrancy (BBB)

• Antidromic Wolf Parkinson White syndrome

• Electrolyte abnormalities or overdoses

Wide Complex TachycardiasDifferential Diagnosis

Irregular• Polymorphic VT (including Torsades)

• A. Fib with aberrancy (BBB)

• A. Fib + accessory pathway

Page 42: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Wide Complex TachycardiasVentricular Tachycardia vs. SVT

Page 43: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Wide Complex Tachycardias

Regular wide complex tachycardia is ventricular tachycardia until proven

otherwise

Page 44: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Wide Complex TachycardiasManagement: Stable, regular WCT

• Consider adenosine ONLY if regular WCT • Procainamide (Class IIa)

• Amiodarone (Class IIb)

• Electrical cardioversionACLS guidelines 2010

*** If ONE anti-arrhythmic fails then proceed to electrical cardioversion***

Page 45: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Case 1: 33 M severe palpitations; healthy; BP 145/85

Case 2: 75 F chest pain; PMHx MI; BP 109/75

Page 46: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Impression: most likely SVT w/ aberrancy

Management • Consider Adenosine – ensure regular rhythm• Other options: Amiodarone, Procainamide, Electrical cardioversion

Impression: most likely VT

Management: • Avoid adenosine • Amiodarone or Procainamide or Electrical cardioversion • Concern about hemodynamic stability

Case 2: 75 F chest pain; PMHx MI; BP 109/75

Case 1: 33 M severe palpitations; healthy; BP 145/85

Page 47: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

FUSION BEAT CAPTURE BEATS

Wide Complex TachycardiasECG Findings Suggestive of VT

AV DISSOCIATION

Page 48: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Wide Complex TachycardiasAccessory Pathways

Orthodromic/AnterogradeQRS typically normalMore common

Antidromic/RetrogradeQRS typically wideLess common

Page 49: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Why do accessory pathways matter?

Wide Complex TachycardiasAccessory Pathways

Wide complex, irregular tachycardia can degenerate to ventricular fibrillation with

AV nodal blockade

Calcium Channel BlockersBeta BlockersAdenosine

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Emergency Medicine

Wide Complex TachycardiasAccessory Pathways

Page 51: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Wide Complex TachycardiasAccessory Pathways

When to suspect accessory pathway?• Rapid ventricular response (>200bpm)• Wide, irregular QRS complexes • Bizarre QRS morphology• History of accessory pathway dysrhythmia

Management• Unstable = Synchronized cardioversion• Check previous ECG for PR interval & Delta wave • Always have defibrillator available with infusions • Amiodarone (AHA 2005 guidelines)

• Procainamide (Intern Emerg Med 2010;5:421-426)

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Emergency Medicine

RecapWide complex tachycardias

• Unstable vs. stable• Synchronized cardioversion if unstable• ONLY try adenosine if convinced it is regular WCT• Assume VT if cardiovascular history or >50yrs • No AV nodal blocker if irregular WCT

Page 53: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

Objectives: recap1. (Very) Briefly review pathophysiology

of arrhythymias (4 slides!)2. Cardioversion3. Tachydysrhythmias4. Special case of wide complex

tachyardia5. Example ECGs

Page 54: Emergency lectures - Arrhythmias & cardioversion andrew petrosoniak

Emergency Medicine

References• Rosen’s Emergency Medicine (7th edition)• Lilly LS. Pathophysiology of heart disease. 2003• Cvphysiology.com• Simplified approach to tachyarrhythmias (EMRap.com)• EMCrit.org• References listed in presentation