ECG Interpretation William A. Shapiro, M.D. Advanced Cardiac Life Support Department of Anesthesia and Perioperative.

ECG InterpretationECG Interpretation

William A. Shapiro, M.D.William A. Shapiro, M.D.

http://anesthesia.ucsf.edu/shapirohttp://anesthesia.ucsf.edu/shapiro

Advanced Cardiac Life SupportAdvanced Cardiac Life Support

Department of Anesthesia and Perioperative Care advancing health worldwide TM

Course Objectives & Description:Course Objectives & Description:

• Recognize & initiate early management of peri-arrest conditions that may result in cardiac arrest

• Manage cardiac arrest until return of spontaneous circulation, or transfer of care

• Understanding of arrhythmia interpretation

• Recognize the hemodynamic consequencesof arrhythmias

Normal Sinus RhythmNormal Sinus Rhythm

Normal sinus rhythm results from the initiation of an Normal sinus rhythm results from the initiation of an

electrical signal (the cardiac impulse) by cells of the electrical signal (the cardiac impulse) by cells of the

sinus node at a rate appropriate to the age and state of sinus node at a rate appropriate to the age and state of

activity of the individual, and then the propagation of activity of the individual, and then the propagation of

that signal in an orderly manner through the atria, A-that signal in an orderly manner through the atria, A-

V junction, ventricular specialized conducting V junction, ventricular specialized conducting

system and the ventricular myocardiumsystem and the ventricular myocardium

Cardiac Conduction System Cardiac Conduction System

Bachmann’s bundle

Left bundle branch

Posterior division

Anterior division

Purkinje fibersRight bundle branch

Bundle of His

AV node

Internodal pathways

Sinus node

ArrhythmiaArrhythmia

An arrhythmia reflects either abnormally rapid or An arrhythmia reflects either abnormally rapid or

slow impulse initiation by the sinus node, or slow impulse initiation by the sinus node, or

interruption of the sinus rhythm by impulses interruption of the sinus rhythm by impulses

originating from some other site in the heart, originating from some other site in the heart,

either for short or long periods of timeeither for short or long periods of time

Mechanisms of ArrhythmiasMechanisms of Arrhythmias

•Reentry

•Automaticity–Altered normal automaticity–Abnormal automaticity

•Triggered Rhythms due to DAD (delayed after depolarizations

Causes of ArrhythmiasCauses of Arrhythmias

• Physiologic and Pathologic Processes–Vagal stimulation, Fever, Hypothermia

–Electrolyte abnormalities, CNS problems

–Hypovolemia, Pain, anaphylaxis, etc.

• Preexisting Cardiac & Pulmonary Disease–Acute coronary syndrome, HTN, AODM

–COPD, hypoxia, hypercarbia

The ElectrocardiogramThe Electrocardiogram

QuickTime™ and a decompressor

are needed to see this picture.

PR Interval

QRS Interval

PR Interval

QRS Interval

QT Interval

Relationship of ECG to anatomy

THE ACLS THE ACLS

PROVIDER PROVIDER

IS:IS: IN

Normal Sinus Rhythm Normal Sinus Rhythm

•Rate 60-100 beats per minute

•Rhythm: Regular

•P waves: Upright in Leads: 1, 2, AVF

Determining the RateDetermining the Rate

Determining the RhythmDetermining the Rhythm

Sinus Tachycardia Sinus Tachycardia

•Rate: Greater than 100 beats per minute

•Rhythm: Regular

Sinus Tachycardia Sinus Tachycardia

•Rate: Greater than 100 beats per minute

•Rhythm: Regular

Sinus Bradycardia Sinus Bradycardia

•Rate: Less than 60 beats per minute

•Rhythm: Regular

Sinus Bradycardia Sinus Bradycardia

•Rate: Less than 60 beats per minute

•Rhythm: Regular

Premature Atrial Complexes Premature Atrial Complexes

•P wave Rhythm: Irregular

•P waves: Premature, often in the T-wave

•QRS complex: Normal or widened

P-wave

•QRS complex: (Normal or widened) or blocked

Non conducted P-wave

Atrial TachycardiaAtrial Tachycardia

• Rate: Atrial- 140-240 bpm, p-waves hard to see

• Rhythm: – P-wave- regular

– QRS- 1-1 conduction with atrial rates < 200 bpm

– With atrial rates > 200 bpm, A-V conduction block common (less than 1-1 conduction)

• PR interval- depends on the origin of the p-wave

• QRS- usually normal

P-Wave

Atrial Tachycardia with variable block

P-Waves are regular at 160 bpm

Atrial FlutterAtrial Flutter

• Rate: Atrial- 300 bpm (260-320)

• Rhythm: – P-waves- regular

– QRS- 2-1 conduction - 150 bpm, variable AV conduction with constant AV conduction ratio

• P-waves: F-waves (Flutter), sawtooth pattern

• QRS- usually normal, obviously sometimes wide

F-waves

Atrial Flutter with variable conduction (block)

Atrial FibrillationAtrial Fibrillation

• Rate: Atrial- rapid, Ventricular- Depends

• Rhythm: – P-waves- irregular

– QRS- beat to beat variability, Irregularly irregular

• P-waves: From F-waves (Flutter) to absent

• QRS duration- normal or wide

Premature Junctional ComplexesPremature Junctional Complexes

•Rhythm: Irregular

•P waves: Retrograde

•PR interval: < .12 sec or nonexistent

Premature Ventricular ComplexesPremature Ventricular Complexes

•P waves: Usually not seen

•QRS complex: Wide > .12 sec

•Compensatory pause

Compensatory pause

This distanceis double the

sinus distance

This is the sinus and the QRSdistance

•Unifocal PVCs

•Multifocal PVCs

Compensatory pause

This distanceis double the

sinus distance

This is the sinus and the QRSdistance

Interpolated PVC

Ventricular Bigeminy

Pairs of PVCs

PVC on T-wave precipitating Ventricular Tachycardia

Ventricular TachycardiaVentricular Tachycardia

•Rate: Approx 100-230 bpm

•Rhythm: Usually regular

•P waves: Usually not seen

– Independent A and V activity

– A-V dissociation

•QRS complex: Wide > .12 sec

•Capture beats, fusion beats

Ventricular TachycardiaVentricular Tachycardia

Polymorphic Ventricular Tachycardia

Ventricular FibrillationVentricular Fibrillation

•Rate: Rapid- no effective cardiac rhythm

•P, QRS, T- waves: Absent

•No blood pressure!

Course VF

Fine VF

Ventricular AsystoleVentricular Asystole

•P, QRS, T- waves: Complete absent of cardiac electrical activity

•Complete absent of effective cardiac pumping function

Acute Coronary SyndromesAcute Coronary Syndromes

ReviewReview

Atrial Fibrillation

ReviewReview

Atrial Fibrillation

Sinus Rhythm

ReviewReview

Atrial Fibrillation

Sinus Rhythm

Acute Coronary Syndrome

ReviewReview

Asystole

ReviewReview

Asystole

Fine Ventricular Fibrillation

ReviewReview

Asystole

Fine Ventricular Fibrillation

Coarse Ventricular Fibrillation

ReviewReview

Ventricular Tachycardia- ?

ReviewReview

Premature Ventricular Complex (PVC)

ReviewReview

Premature Ventricular Complex (PVC)

Ventricular Tachycardia

ReviewReview

(Paroxsymal) Atrial Tachycardia (SVT)

ReviewReview

Paroxsymal Atrial Tachycardia (SVT)

ReviewReview

Paroxsymal Atrial Tachycardia (SVT)

Atrial Flutter

Treatment of All Cardiac Arrhythmias

All arrhythmias that are

hemodynamically significant

require immediate

cardioversion, defibrillation,

or cardiac pacing

Break Time

AV BlockAV Block

•Why is it important?

•Where is the block?

•What’s a pacemaker anyway?

Rates of Intrinsic Cardiac Pacemakers

•Primary pacemaker

–Sinus node (60-100 bpm)

•Escape pacemakers

–AV junction (40-60 bpm)

–Ventricular (< 40 bpm)

Escape PatternsEscape Patterns

Junctional Escape ComplexesJunctional Escape Complexes

•Rate: Junctional escape rate 40-60 bpm

•Rhythm: Junctional

•P-waves: Retrograde, inverted in 2,3, avf

–Before, during, or after QRS

•QRS: Normal or wide

Junctional Rhythm

Ventricular Escape ComplexesVentricular Escape Complexes

Classification of AV BlockClassification of AV Block

•Partial– First-degree AV block– Second-degree AV block,

Types I (Wenckebach) and Type II

•Complete AV block– Third-degree AV Block

“You should know the major AV blocks because important treatment decisions are based on the type of block present.” Page 79

First-Degree AV BlockFirst-Degree AV Block

•Rhythm: Regular

•1:1 Conduction: Each P-wave is followed by a QRS complex

•PR Interval: > .20 secs

•QRS Complex: Generally normal

•Hemodynamic implications: None

First-Degree AV BlockFirst-Degree AV Block

Second-Degree AV Block, Type ISecond-Degree AV Block, Type I

• Rate: – Atrial- regular– Ventricular- less than the atrial rate

• Rhythm: – Atrial- regular– Ventricular- progressive shortening of

the R-R interval before pause• PR: progressive increase until P blocked

• Why is knowing this important

Second-Degree AV Block, Type ISecond-Degree AV Block, Type I

Second-Degree AV Block, Type IISecond-Degree AV Block, Type II

• Rhythm: – Atrial- regular– Ventricular- usually irregular

• PR: constant when present• Why is knowing this important

Second-Degree AV Block, Type IISecond-Degree AV Block, Type II

Third-Degree AV Block Third-Degree AV Block

• Rhythm: – Atrial- regular– Ventricular- regular

• PR: varies with every beat• QRS: normal or wide• Hemodynamics: No atrial contribution

Third-Degree AV Block Third-Degree AV Block

All arrhythmias that are

hemodynamically significant

require immediate

cardioversion, defibrillation,

or cardiac pacing

Electrical TherapyElectrical Therapy

• Understand when cardioversion or defibrillation is indicated

• Know the difference between unsynchronized and synchronized shocks

• Energy doses for specific rhythms

• Challenges of delivering shocks safely and effectively- may include iv sedation

Electrical TherapyElectrical Therapy

Cardioversion and DefibrillationCardioversion and Defibrillation

• Understand when cardioversion or

defibrillation is indicated

SYMPTOMS

Hemodynamically SignificantHemodynamically Significant

Tachycardia or Bradycardia

• Hypotension (Systolic BP < 80 mmHg)

• Altered mental status

• Congestive heart failure

• Angina

• Does not respond promptly to medical

management, if tried

Defibrillation

The electric shock depolarizes all

excitable myocardium, interrupts

reentrant circuits, discharges

foci, and establishes electrical

homogeneity

Defibrillation

• AED: Learn the one in your setting

• Biphasic: 200 watt-seconds (joules)

• Monophasic: 360 watt-seconds (joules)

“The interval from collapse to defibrillation is

one of the most important determinants of

survival from cardiac arrest.” Page 35

• Power on

• Apply pads

• Analyze the rhythm

• Select the energy level

• Clear the area

• Discharge the device

Procedure for Defibrillation

Cardioversion

• Know when cardioversion is indicated

• Synchronized vs unsynchronized shock

• What energy level for what arrhythmias

• Establish iv and consider sedation

Cardioversion

A physician skilled in airway management

(ie., an anesthesiologist) should be in

attendance, and all necessary equipment

for emergency resuscitation should be

immediately available

Anesthetic (amnestic) Agents

Cardioversion

The electric shock depolarizes all

excitable myocardium, interrupts

reentrant circuits, discharges

foci, and establishes electrical

homogeneity

Synchronization

Synchronized cardioversion (defibrillation) uses

a sensor to deliver the shock with the peak of the

QRS complex. The goal is to avoid the shock on

the T-wave, “R-on-T”, which is known to induce

ventricular fibrillation in unstable hearts

PR Interval

QRS Interval

QT Interval

• Atrial flutter & SVT: 50-100 J (monphasic)

• Atrial fibrillation: 100-200 J (monophasic)

• Ventricular tachycardia: 100-200 J

Synchronization

Energy Selection

• Power on

• Apply pads

• Turn on the SYNC control

• Analyze the rhythm

• Select the energy level

• Clear the area

Procedure for Cardioversion

• Ventricular fibrillation occurs

• Turn off the SYNC control

• Charge to 200 J (or more)

• Clear the area

Complications of Cardioversion

ReviewReview

3rd Degree Heart Block

ReviewReview

2nd Degree Type II Block

ReviewReview

2nd Degree Type II Block

2nd Degree Type I Block

ReviewReview

1st Degree Heart Block

ReviewReview

Junctional Escape Rhythm

ReviewReview

Junctional Escape RhythmJunctional Escape Rhythm

Sinus Bradycardia

ReviewReview

ECG InterpretationECG Interpretation

William A. Shapiro, M.D.William A. Shapiro, M.D.http://anesthesia.ucsf.edu/shapirohttp://anesthesia.ucsf.edu/shapiro

Advanced Cardiac Life SupportAdvanced Cardiac Life Support

Department of Anesthesia and Perioperative Care advancing health worldwide TM

That’s it- Now go forthThat’s it- Now go forthand save lives-and save lives-

Make us all proud you’re from UCSFMake us all proud you’re from UCSF

ECG Interpretation William A. Shapiro, M.D. Advanced Cardiac Life Support Department of Anesthesia and Perioperative.

rhythm slide

rate slide

avf slide

electrocardiogram slide

widened slide

acls slide

hypercarbia slide

widened pwave slide

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