SHA24/046002

Gulf Heart Association 10 Saudi Heart Association 24

Basic Rhythm Interpretation Yvonne Kaveney Head Nurse Paediatric Cardiac Surgery Ward Prince Sultan Cardiac Center

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Today’s Workshop • Electrical and mechanical activity of the heart

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Today’s Workshop • Basic rhythm analysis

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Electrical and Mechanical Activity of the Heart

OBJECTIVES • Very quickly ……..

–Consider cardiac function –Describe the cardiac conduction system –Explain cardiac electrical activation –Discuss cardiac mechanical activity –View normal ECG components

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Cardiac Function • Pump Contraction • Cardiac output Pulse Blood pressure • Organ perfusion pressure Organ function Peripheral flow Capillary refill

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Cardiac Function • Pump • Muscle

• Stimulus • Contraction 7

Cardiac Stimulation • Electricity

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Cardiac Stimulation • Electricity • Electrolytes

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Cardiac Stimulation Cardiac cell Kkk

Depolarisation

Repolarisation

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Cardiac Stimulation • Electricity • Electrolytes

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Cardiac Stimulation • Electricity • Electrolytes

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Cardiac Stimulation • Electricity • Electrolytes • Electrodes • Electrocardiogram

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Is It Cardiac Electrical Activity?

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Is It Cardiac Electrical Activity?

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Conduction System

SA Node AV Node Purkinje Fibers AV Bundle

Rt Bundle Branch

Lt Bundle Branch

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Conduction

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Atrial Conduction

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AV Node Conduction

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Ventricular Conduction

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Ventricular Conduction

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Ventricular Conduction

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Cardiac Electrical Activity on ECG

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ECG paper

• 1 small square

=

0.04 secs

• 5 small squares

=

1 large sq

• 1 large square

=

0.20 sec (5 x 0.04)

• 5 large squares

=

1 sec 24

The Isoelectric Line

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Atrial Conduction – P Wave

• Not taller than 3 mm • 0.06 +/- 0.02 secs in paeds • 0.06 – 0.11 secs in adults

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AV Conduction – PR Interval

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AV Conduction – PR Interval

• 0.12 – 0.20 secs in adults or 3-5 small sq’s

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Ventricular Depolarisation – QRS Complex

• 0.06 – 0.10 secs in adults

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Ventricular Depolarisation – ST Segment

• Should be isoelectric • 1 mm depression or elevation acceptable in limb leads

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QT Interval Duration

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Ventricular Activity – QT Interval

• 0.36 – 0.44 secs in adults

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Components of the ECG

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Interpretation – The 11 Step Method 1.

Other

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Evaluate the P wave

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Determine the rhythm

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Determine the rate

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Calculate PR interval duration

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Calculate QRS complex duration

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Evaluate the T wave

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Calculate QT interval duration

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Evaluate any other components

10. Interpretation 11. Treatment

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Basic Rhythm Analysis OBJECTIVES • Recognise rhythms originating from: –The atria –The AV junction –The ventricles

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Atrial Rhythms Have a P

WAVE

•Sinus Rhythm •Sinus Bradycardia •Sinus Tachycardia 37

Sinus Rhythm

• • • • •

P waves present and normal 1:1 P / QRS conduction Regular Normal rate for age Normal PR interval

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Premature Atrial Contractions (PACs)

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Atrial Flutter

• • • • • •

Single or multiple atrial foci Atrial rate 250 – 350 Flutter waves look similar Atrial rhythm regular QRS normal Ventricular rhythm regular or irregular

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Atrial Fibrillation

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Atrial Fibrillation

• • • • • • •

Multiple atrial foci Atrial rate 350 - 450 Fibrillation waves all look different Baseline may be chaotic (no clear P waves) or flat Atrial rhythm irregular Ventricular rhythm irregular QRS normal

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Junctional Rhythms Produce a NARROW

QRS

•Premature Junctional Contractions •Junctional Tachycardia

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Premature Junctional Contractions (PJCs)

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Premature Junctional Contractions (PJCs)

• • • • •

PJCs appear early Rhythm irregular around PJC P waves may be absent or present but are inverted QRS narrow PJC may distort previous T wave

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AV Node Behavior



 46

Junctional Tachycardia

• • • •

Regular rhythm QRS complex within normal limits Ventricular rate > 100 (150 – 250) Inverted P wave may or may not be seen

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Ventricular Rhythms Produce a WIDE

QRS

• Premature Ventricular Contractions • Ventricular Tachycardia • Ventricular Fibrillation 48

Premature Ventricular Contractions (PVCs)

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Premature Ventricular Contractions (PVCs)

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PVCs appear early Rhythm irregular around PJC QRS broad and bizarre (> 0.12 secs) T wave opposite direction to the QRS A compensatory follows the PVC

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Premature Ventricular Contractions (PVCs)

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Unifocal / Multifocal PVCs

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Premature Ventricular Contractions (PVCs) Paired PVCs

Multiform PVCs

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Premature Ventricular Contractions (PVCs) Bigeminy and Trigeminy

R-on-T Phenomenon

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Ventricular Tachycardia (Monomorphic)

• • • •

Absent P waves QRS complexes broad and bizarre (> 0.12 secs) T wave opposite direction to the QRS Rate > 100 (150 – 250)

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Torsades de Pointes (Polymorphic VT)

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Ventricular Fibrillation

• No P waves • No clear QRS complexes • Multiple ventricular ectopic foci producing only fibrillatory waves

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Asystole

• Absent P waves • Absent QRS complexes

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Escape Rhythms

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Escape Rhythms

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Atrioventricular Blocks • 1o AV Block • 2o AV Block Mobitz 1 / Wenckebach • 2o AV Block Mobitz 2 • 3o AV Block / Complete Heart Block

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10 AV Block

• P waves present and normal • 1:1 conduction of P waves:QRS complexes • PR interval prolonged

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20 AV Block Type I – Mobitz I / Wenkebach

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20 AV Block Type I – Mobitz I / Wenkebach

• P waves present and normal • PR interval lengthens until a QRS complex is dropped • Series repeats (footsteps)

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20 AV Block Type II – Mobitz II

• • • •

P waves present and normal PR interval usually normal Without warning, QRS complexes are dropped PR interval constant for all conducted beats

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30 AV Block – Complete Heart Block

• • • • •

Atrial and ventricular activity unrelated Atrial and ventricular rhythms both regular Atrial rate faster than ventricular rate PR intervals vary (keep changing) throughout rhythm QRS width depends on origin of ventricular escape focus

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30 AV Block – Complete Heart Block

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YOUR TURN NOW!

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Junctional Tachycardia 69

Atrial Fibrillation 70

Sinus Bradycardia 71

Ventricular Tachycardia 72

Junctional Tachycardia 73

Atrial Flutter 74

2nd Degree Heart Block Type II 75

Sinus Rhythm with IVCD 76

Ventricular Standstill 77

Sinus Rhythm with Ventricular Bigeminy 78

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References Woods, S.L., Froelicher, E.S., Underhill Motzer, S., Bridges, E.J (2005) Cardiac Nursing (5 th Edition) Lippincott, Philadelphia Conover, M.B. (2003) Understanding Electrocardiography (8 th Ed.) Mosby-Year Book, Inc., Missouri Jackson, K., Mayer, B., Duksta, C., Eggenberger, T., Folllin, S.A, Robinson, K. (2002) ECG Interpretation made Incredibly Easy (2nd Ed.) Springhouse Corporation, USA Hazinski, M., Cummins, R.O. & Field, J.M (2000) 2000 Handbook of Emergency Cardiovascular Care for Healthcare Providers American Heart Association, Texas Dubin, D. (2000). Rapid Interpretation of EKG’s COVER Publishing Company, Florida Huff, J. (1997) ECG Workout – Exercises in Arrhythmia Interpretation (3 rd Ed.) Lippincott, Philadelphia

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