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ECG Interpretation Chapter 22.

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Presentation on theme: "ECG Interpretation Chapter 22."— Presentation transcript:

1 ECG Interpretation Chapter 22

2 ECG Interpretation Rate Atrial rate: PP interval
Ventricular rate: RR interval Rhythm P wave PR interval QRS voltage (height) width Axis Hypertrophy Blocks Infarct Ischemia

3 Standardization Standardization mark
10 mm vertical deflection = 1 mVolt

4 Rate Ventricular rate (heart rate) Atrial rate 3rd degree AV block
RR interval Atrial rate PP interval 3rd degree AV block

5 Heart Rate Calculation
1500 divided by the number of small boxes between two R waves most accurate take time to calculate only use with regular rhythms 1 lg sq = 300 bpm 2 lg sq = 150 bpm 3 lg sq = 100 bpm 4 lg sq = 75bpm 5 lg sq = bpm 6 lg sq = bpm 300 divided by the number of large boxes between two R waves quick not too accurate only use with regular rhythm 10 multiplied by the number of R waves in 6 seconds less precise use with irregular rhythms very quick

6 Rhythm Sinus rhythm - consistent P waves
Atrial rhythm - irregular P waves Junctional/Nodal rhythm - no P waves, late P waves, or inverted P waves Ventricular rhythm - no P waves, wide QRS

7 AV Junctional Rhythms Retrograde P waves immediately preceding the QRS complexes in aVR and II. Retrograde P waves immediately following the QRS complexes Absent P waves

8 ECG Waves P wave atrial depolarization ≤ 2.5 mm in amplitude
< 0.12 sec in width PR interval ( sec.) time of stimulus through atria and AV node prolonged interval = first-degree heart block

9 P wave Tall = RAE Wide = LAE

10 PR Interval Long PR interval = first degree AV block
Short PR interval = WPW Short PR interval with inverted P waves = ectopic atrial or junctional pacemaker

11 Classification of AV Heart Blocks
Degree AV Conduction Pattern 1St Degree Block Uniformly prolonged PR interval 2nd Degree, Mobitz Type I Progressive PR interval prolongation 2nd Degree, Mobitz Type II Sudden conduction failure 3rd Degree Block No AV conduction

12 Wolff-White-Parkinson
Wide QRS due to early depolarization not due to a delay in depolarization Shortened PR interval Upstroke QRS complex is slurred; delta wave

13 ECG Waves QRS width 0.12 second or less

14 Normal QRS V6? V6? V1? V1? Fig. 4-6

15 Normal Q waves Septal r wave Septal q wave

16 Q Waves Abnormal if wider than 0.04 sec Greater than 25% of the R wave
Leads I, II, III, aVf or leads V3 - V6. Greater than 25% of the R wave Note: Not all Q waves are abnormal, Not all Q waves are the result of MI.

17 QRS Width Wide RBBB or LBBB Premature ventricular beats WPW

18 QRS Voltage RVH LVH

19 Mean QRS Axis

20 Axis Deviation (or Lead II or III) LEAD I LEAD aVF LEAD aVR Normal
Positive LAD Negative RAD (or Negative) Intermediate axis

21 R Wave Progression

22 Transmural MI Pathalogical Q waves ST segment elevation.
Ischemia Tall T waves (and/or reciprocal T wave inversion) Injury ST segment elevation. T wave inversion of the previously tall T waves Infarct Pathalogical Q waves (at least one small box wide or 11/3 the entire QRS height)

23 Posterior (reciprocal)
Overview LEAD AREA OF THE HEART V1-V2 Anterior/Septum V3-V4 Anterior Wall V5-V6 Anterior/Lateral II, III, aVF Inferior I and aVL Lateral Posterior (reciprocal)

24 ST Segments J point: end of QRS wave beginning of ST segment
beginning of ventricular repolarization normally isoelectric (flat) changes, elevation or depression, may indicate pathological condition

25 Subendocardial Ischemia
ST segment depression criteria 1 mm or more horizontal or downward lasts 0.08 seconds depression of only the J point with rapid upward sloping are considered normal.

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