Top Banner
BASIC ECG INTERPRETATION
95
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 3: ECG Interpretation

Heart Conduction

Page 4: ECG Interpretation

Electrical Conduction Rate

• SA node • Rate: 60 – 100 bpm

• AV node • act as back-up pacemaker• Rate: 40 – 60 bpm

• Purkinje Fiber • can act as back-up pacemaker

• Rate: 20 – 40 bpm

Page 5: ECG Interpretation

Breakdown of ECG strip

Page 6: ECG Interpretation

P wave: (SA node fires)

• Atrial depolarization

• Normal shape: upright & round

.

Components of the Cardiac Cycle

Page 13: ECG Interpretation

STEPS IN ANALYSING ECG

Page 14: ECG Interpretation

Step I: rhythm• Regular

• irregular

Page 15: ECG Interpretation

Step II: Rate

• Normal: 60 – 100 bpm

• Bradycardia: < 60 bpm

• Tachycardia: > 100 bpm

Page 16: ECG Interpretation

HEART RATE CALCULATION

Page 17: ECG Interpretation

Method I

•For regular rhythm:• Count the number of large boxes between 2 R waves and that number is divided into 300.

• Remember: • .20 sec/large box = 5 large boxes/sec.• 60 sec/min x 5 = 300 large boxes/min.

Page 18: ECG Interpretation

What is the rate?

Rate: 300 / 4 = 75 bpm

Page 19: ECG Interpretation

Method II• For fast heart rate:

• count the number of small boxes between two R waves and that number is divided into 1500

• Remember: • 5 small boxes/large box• 300 large boxes/min• 300 x 5 = 1500

Page 20: ECG Interpretation

What is the rate?

Rate: 1500 / 10 = 150 bpm

Page 21: ECG Interpretation

Method III• For irregular rhythm:

• Count the R waves in 6 sec strip (between 3 hash marks) and multiply it by 10.

• Remember: 5 large boxes / sec

Page 22: ECG Interpretation

Method IV:• Find the R wave that fall on a large box line. Level the next large box line a rate of 300 – 150 - 100 – 75 – 60 – 50 – 43 – 37 – 33 & 30, until the next R wave.

Page 23: ECG Interpretation

Step 3 P wave• configuration: round and upright • Location: precedes QRS complex• Duration: .06 -.11 sec. (1.5 – 2.5 small boxes)• Amplitude: up to 2.5mm

Page 24: ECG Interpretation

• To ask:• Are P wave present?• Do they look the same?• Is there P before every QRS?

Page 25: ECG Interpretation

Other P wave configurations

Page 26: ECG Interpretation

Step 4: PR interval• From the start of Atrial depolarization to the beginning of

ventricular depolarization

• Location: beginning of P wave to beginning of Q wave

• Duration: .12 - .20 sec

• Amplitude: not measured

• Configuration: P wave followed by isoelectric line

• To ask?• Are all P-R intervals consistent?

Page 27: ECG Interpretation

P-R interval (PRI)

Page 28: ECG Interpretation

Step 5: QRS complex• Ventricular depolarization / atrial repolarization• Location: follows P-R interval• Amplitude: varies with lead• Duration: .04 -.12 (1-3 small boxes)• Configuration: varies with lead

Page 29: ECG Interpretation

to ask?Are there QRS? Do they look the same?Do they come after the P wave?Are the R – R intervals equal?

Page 30: ECG Interpretation

Configuration

Page 32: ECG Interpretation

ST segment• End of ventricular depolarization to the beginning of

ventricular repolarization• Location: end of S wave to beginning of T wave• Amplitude: isoelectric• Duration: not measured• Configuration: nearly isoelectric

Page 33: ECG Interpretation

Configuration • Isoelectric• Elevated (> 1 – 2 mm)

• Sign of acute MI• Depressed (> .5 mm)

• Sign of ischemia

Page 34: ECG Interpretation

QT interval• Location: beginning of Q wave to end of T wave• Amplitude: not measured• Duration: < ½ the distance of the R-R interval• Configuration: not measured

Page 36: ECG Interpretation

ARTIFACTS

• First Rhythm Strip to Identify 31.

Page 37: ECG Interpretation

ARTIFACTS

Four Common Causes: • Patient Movement • Loose or defective electrodes • Improper grounding • Faulty ECG apparatus

Page 38: ECG Interpretation

SINUS RHYTHMS

Page 39: ECG Interpretation

Mechanism: Rhythm originates in the SA node

1.

• ECG characteristics• Rhythm: regular• Rate: normal (60 – 100 bpm)• P wave: normal / 1 per QRS complex• PR interval: normal (.12 - .20 sec)• QRS complex: normal (.04 - .12 sec)• ST segment: not elevated or depressed• T wave: normal

Page 40: ECG Interpretation

Normal sinus rhythm• Etiology: Normal cardiac function

• Clinical Tip: A normal ECG does not exclude heart disease.

Page 41: ECG Interpretation

• Mechanism:

• depressed automaticity of the SA node with normal conduction

2.

• ECG characteristics:• all normal• rate - < 60

Page 42: ECG Interpretation

Sinus BradycardiaEtiology:

• sleeping; young, athletic individuals• Excessive vagal tone (straining, vomiting, intubation)• Sick sinus syndrome, MI • Digoxin toxicity, Sedative• Hyperkalemia• Trauma to conductive system

Clinical signs: low CO low perfusion lethargy, mental status change, anxiety, poor capillary refill, mottled skin, low UO syncope

Page 43: ECG Interpretation

BradycardiaNursing action: (if symptomatic)• Document rhythm & notify MD • Apply O2 & consider atropine• Prepare for external pacing• If with PVCs – don’t treat with lidocaine (this is the heart’s

attempt to improve perfusion)• Atropine SO4

• 0.5 mg IV (may repeat in 3-5 min)• Maximum dose: 3 mg• Do not give < 0.5 mg may worsen the bradycardia• Do not push slow

Page 44: ECG Interpretation

Mechanism: • increased automaticity of the SA node with normal conduction

3.

• ECG characteristics: • all normal• Rate: 101 – 160 bpm• P wave: normal or merge to T wave

Page 45: ECG Interpretation

Sinus tachycardiaEtiology: • a natural response to environmental stimuli – pain, fever, exercise,

emotion, dehydration• Drugs, caffeine, alcohol, Hyperthyroidism, shock, CHF, hypoxia

Clinical signs:• Increased workload of the heart decrease CO low perfusion

angina, SOB, anxiety, hypotension, low UO

Nursing action: if symptomatic• Document rhythm & notify MD• Apply O2• Treat underlying cause• May consider vagal maneuver

• cough, bear down, blow through straw • try blowing plunger off the syringe

Page 46: ECG Interpretation

Mechanism:

reflux vagal tone inhibition associated with respiration. (rate increases with inspiration & drops with exhalation)

4.

ECG characteristics:• Rhythm: irregular• Others: All normal

Page 47: ECG Interpretation

Sinus ArrhythmiaEtiology:

• Normal phenomenon with inspiration (esp, in infant)• Digitalis toxicity, MI, increased ICP• Fever, anxiety, shock

Nursing action:• Document rhythm & notify MD if symptomatic• No treatment

Page 48: ECG Interpretation

• Mechanism:

• Signal to SA node is not generated or it fails to leave the SA node

5.

• Sinus pause / block - Basic rhythm resumes after a pause

• ECG Characteristics:• Rhythm: irreg• Rate: normal or < 60 • Other waves: Normal except during pause or arrest

Page 49: ECG Interpretation

Sinus arrest – basic rhythm does not resume after a pause

6.

Page 50: ECG Interpretation

Sinus pause/arrest/block• Etiology:

• High vagal tone or increased vagal stimulation• Drug toxicity (esp. digoxin)• MI, s/p cardiac surgery, SA node trauma• lupus, metabolic disorders

• Clinical signs:• If HR is <50 decreased CO hypotension, changes in mental

status and fatigue

• Nursing Action if symptomatic• Document the rhythm • Apply O2• Consider atropine• Consider pacemaker

Page 51: ECG Interpretation

ATRIAL DYSRHYTHMIAS

Page 52: ECG Interpretation

(PAC)Mechanism: (early P) premature beat originate from the Atria • 7.

ECG characteristics:• Rhythm: irreg during the beat• Rate: varies• P wave: different from normal P wave• PRI: varies during the beat• QRS com / ST seg: Normal• T wave: may be distorted during the beat

Page 53: ECG Interpretation

Premature Atrial Contraction (PAC)• Etiology:

• Stress, stimulants, alcohol, overeating• Electrolyte imbalance, drug toxicity (digoxin)• Pericarditis, MI, ischemia, COPD

• Clinical signs:• >10 PACs = CHF• Palpitations

• Nursing Action:• Document• Treat underlying cause

Page 54: ECG Interpretation

AF• Mechanism:

• Atrial quiver with ventricular response (> 100 = RVR (rapid) / 60 =100 – CVR (controlled)) blood clots

8.

• ECG Characteristics:• Rhythm: irreg• Rate: Atria: 350-600 / Ventricle: varies• P wave: none ( F wave)• QRS comp: Normal• Others: not measurable

Page 55: ECG Interpretation

Atrial Fibrillation• Etiology:

• Atrial enlargement due to AV valve disorders• Hpn, CAD, COPD, CHF, MI• Hypoxia, drugs, digitoxicity, tobacco

• Clinical signs:• Irregular pulse, palpitation, anxiety, SOB CHF shock

• Nursing Action:• Document rhythm & inform MD• Apply O2• Possible Synchronize cardioversion• Anticoagulant therapy

Page 56: ECG Interpretation

• Mechanism:• Extremely rapid atrial rate (saw-tooth configuration)

9.

• ECG characteristics:• Rhythm: irreg / regular• Rate: Atria: 250-350 / ventricle: varies• QRS comp: Normal• Others: not measurable

Page 57: ECG Interpretation

Atrial Flutter• Etiology:

• Related to underlying heart disease • Hyperthyroidism, alcoholism

• Clinical signs:• decreased CO hypotension, mental status change,

fatigue, CHF, SOB

• Nursing Action if symptomatic:• Document rhythm & notify MD• Apply O2• Vagal maneuver

• If tachycardic – consider synchronize cardioversion

Page 58: ECG Interpretation

PAT / SVT

• Mechanism: impulse originate above the ventricle, due to rapid rate loss of atrial kick

• 10.

• ECG characteristics:• Rhythm: regular• Rate: 140 – 250 bpm• P wave: hidden in T wave• QRS comp: normal• PRI: not measurable

Page 59: ECG Interpretation

Paroxysmal Atrial tachycardia (PAT) / Supraventricular tachycardia• Etiology• Heart diseases, emotional stress• Regular atrial rhythm• Digitalis toxicity

• Clinical sign: loss of atrial kick decrease CO decreased perfusion myocardia ischemia

• Nursing Action:• Treat the cause• Valsalva maneuver or carotid massage

Page 60: ECG Interpretation

JUNCTIONAL DYSRHYTHMIAS

Page 61: ECG Interpretation

Junctional rhythm / junctional escape rhythm

• Mechanism:• Rhythm originate from AV junctional tissue (maybe an escape rhythm,

enhanced automaticity of the AV node that override the SA node)

11.

• ECG characteristics:• Rate: 40 – 60 bpm• P wave: inverted or none or retrograde • PRI: shortened• QRS comp: normal• Others – normal unless distorted by the P wave

Page 62: ECG Interpretation

Accelerated junctional rhythm:

12.

• Rate: 61 – 100 bpm

• Nursing action: same as junctional rhytm

Page 63: ECG Interpretation

Junctional tachycardia

13.

• Rate: 101 – 180 bpm

Page 64: ECG Interpretation

Junctional rhythm• Etiology:

• SA node failure due to vagal stimulation, IHD, valve surgery, Rheumatic fever, hypoxia, drug toxicity (digitalis, quinidine)

• Usually no symptoms• Low CO due to slower HR and loss of atrial kick syncope,

hypotension & other CNS symptoms

• Nursing Action:• Document rhythm & notify MD• Apply O2• Treat underlying cause• Consider atropine• Consider pacemaker

Page 65: ECG Interpretation

• Mechanism: conduction defect at the bundle branches• Shows RSR wave or notched QRS complex “rabbit ear”

14.

• ECG characteristics:• QRS comp: >.20 sec.• ST segment: maybe depressed• T wave: maybe inverted• Others: normal

Page 66: ECG Interpretation

Bundle branch Block (BBB)• Etiology:

• MI, ischemia, chronic conduction disorder

• Clinical sign• None

• Nursing Action:• Document rhythm and notify MD if new onset• Be aware that left BBB causes bizarre ST segment that may mask

signs of acute MI

Page 67: ECG Interpretation

AV HEART BLOCKSIt is a delay or failure of the impulse across the AV node

Page 68: ECG Interpretation

• the sinus impulse is conducted normally to the AV node

but there is a delay before being conducted to the ventricles

15.

• ECG characteristics:• All normal except for Prolonged PRI (>.20 sec)

Page 69: ECG Interpretation

• Etiology:• Drugs – quinidine, digitalis, beta blockers, calcium channel

blockers, procainamide• Acute inferior wall MI, Increase vagal tone, Hyperkalemia

• Tx: none

Page 70: ECG Interpretation

SECOND DEGREE AV BLOCK Type I – Mobitz I or WenckebachType II – Mobitz II

Page 71: ECG Interpretation

• 1 or more impulses are unable to travel through the AV junction

16.

• Rate: Depends on rate of underlying rhythm• Rhythm: Irregular• P Waves: Normal (upright and uniform)• PR Interval: Progressively longer until one P wave is blocked

and a QRS is dropped• QRS: Normal (0.06–0.10 sec)

Page 72: ECG Interpretation

Mobitz I• ♥ Clinical Tip: This rhythm may be caused by medication

such as beta blockers, digoxin, and• calcium channel blockers. Ischemia involving the right

coronary artery is another cause.

Page 73: ECG Interpretation

Mechanism:

• Damage of the AV junction below the bundle of HIS SA or AV beat cannot depolarize the ventricle

17.

• ECG characteristics:• P wave – 2 or more P wave for every QRS complex• PRI – normal or prolonged• QRS: normal or wide

Page 74: ECG Interpretation

Mobitz II• Etiology:

• AMI, ischemia, s/p cardiac surgery, CAD, degenerative dis of conductive system

• Drug toxicity

Page 75: ECG Interpretation

• There is no correlation between the conduction of the atria

& ventricle18.

Page 76: ECG Interpretation

Complete heart block• Rate: Atrial: 60–100 bpm; ventricular: 40–60 bpm • Rhythm: Usually regular, but atria and ventricles act

independently• P Waves: Normal (upright and uniform); may be

superimposed on QRS complexes or T waves• PR Interval: Varies greatly• QRS: normal

Page 77: ECG Interpretation

VENTRICULAR RHYTHM

Page 78: ECG Interpretation

(PVC)• Ectopic beats that originate in• the ventricle abnormal QRS complex.

19.

• ECG characteristics:• Rhythm: regular / becomes irreg with PVC• Rate: within normal• P wave: none associated with PVC• PRI: not measureable• QRS: wide & bizarre• T wave: in opposite direction of the wide QRS

Page 79: ECG Interpretation

PVCs: bigeminy

20.

Page 80: ECG Interpretation

PVCs: trigeminy

21.

Page 81: ECG Interpretation

22.

Page 82: ECG Interpretation

23.

Page 83: ECG Interpretation

PVCs: quadrigeminy

24.

Page 84: ECG Interpretation

PVCs: couplets

25.

Page 85: ECG Interpretation

Premature Ventricular Contraction (PVC)

• Causes:• Hypokalemia, hypocalcemia• Caffeine, tobacco, alcohol, exercise• Drug toxiciy• MI, CHF, Hypoxia

• Tx; • 1st line – lidocaine followed by procainamide, bretylium

• 6 PVCs/min is pathologic

Page 86: ECG Interpretation

• QRS complexes in polymorphic VT vary in shape and amplitude.

26.

• ■ The QT interval is normal or long.• Rate: 100–250 bpm• Rhythm: Regular or irregular• P Waves: None or not associated with the QRS• PR Interval: None• QRS: Wide (0.10 sec), bizarre appearance

Page 87: ECG Interpretation

Ventricular tachycardia (V-tach)• ♥ Clinical Tip: It is important to confirm the presence or

absence of pulses because• polymorphic VT may be perfusing or nonperfusing.

• ♥ Clinical Tip: Consider electrolyte abnormalities as a possible etiology.

Page 88: ECG Interpretation

idioventricular rhythm / agonal rhythm

27.

• Rate: 20–40 bpm• Rhythm: Regular• P Waves: None• PR Interval: None• QRS: Wide (0.10 sec), bizarre appearance

Page 89: ECG Interpretation

Accelerated Idioventricular rhythm

28.

• Rate: 41–100 bpm• Rhythm: Regular• P Waves: None• PR Interval: None• QRS: Wide (0.10 sec), bizarre appearance• ♥ Clinical Tip: Idioventricular rhythms appear when supraventricular pacing sites

are• depressed or absent. Diminished cardiac output is expected if the heart rate is

slow.

Page 90: ECG Interpretation

Torsade de pointes• The QRS reverses polarity and the strip shows a spindle effect.• ■ This rhythm is an unusual variant of polymorphic VT with normal or

long QT intervals.

29.

Rate: 200–250 bpm• Rhythm: Irregular• P Waves: None• PR Interval: None• QRS: Wide (0.10 sec), bizarre appearance

Page 91: ECG Interpretation

Torsade de pointes• In French the term means “twisting of the points.”• ♥ Clinical Tip: Torsade de pointes may deteriorate to VF

or asystole.• ♥ Clinical Tip: Frequent causes are drugs that prolong

QT interval and electrolyte• abnormalities such as hypomagnesemia.

Page 92: ECG Interpretation

• Chaotic electrical activity occurs with no ventricular

depolarization or contraction.

30.

• Rate: Indeterminate• Rhythm: Chaotic• P Waves: None• PR Interval: None• QRS: None

Page 93: ECG Interpretation

♥ Clinical Tip: • There is no pulse or cardiac output. • Rapid intervention is critical. • The longer the delay, the less the chance of conversion.

• ECGs

Page 94: ECG Interpretation

• Electrical activity in the ventricles is completely absent.

• Rate: None• Rhythm: None• P Waves: None• PR Interval: None• QRS: None• ♥ Clinical Tip: Always confirm asystole by checking the ECG in two

different leads. Also,• search to identify underlying ventricular fibrillation.

Page 95: ECG Interpretation

THANK YOU FOR LISTENING!!!