Normal ECG Rate and Rhythm Read chapters 4

Normal ECG: Rate and Rhythm Read chapters 4 and 22

ECG Interpretation* Standardization Rate 1. RR interval 2. Heart rate Rhythm 3. PP interval 4. P wave width, height, shape, etc. 5. PR interval 6. QRS width (and height) *See Chapter 22

ECG Interpretation Univ. of Wisconsin Medical School • http: //www. fammed. wisc. edu/pcc/ecg/

The Normal ECG Normal = normal sinus rhythm

Rate 1. R-R interval Is it regular? 2. What is the heart rate? 300, 150, 100, 75, 60, 50 300 / (# of large boxes) 1500 / (# of small boxes) Count the number of cardiac cycles in 10 seconds and multiple by 6.

Rate Bradycardia less than 60 bpm Tachycardia greater than 100 bpm

Rate 3. P-P interval

Rhythm 4. P wave 5. PR interval 6. QRS

4. P Wave Lead II and a. VR Positive in II Negative in a. VR < 2. 5 mm in amplitude < 0. 12 sec. in width

Normal P Wave Normal direction of atrial depolarization a. VR? II? Figures 4 -2 and 4 -3

Abnormal P Wave Direction of atrial depolarization with junction rhythm This is an example of a retrograde conduction a. VR? II?

P wave The same direction as QRS Only one P wave in front of QRS Do all the P waves look alike?

5. PR interval 0. 12 - 0. 20 seconds

6. QRS Complex What is the width? (less than 0. 10 seconds) Do all the QRS waves in the same lead look alike? R wave progression Axis Abnormal Q waves (infarction)

QRS Complex Q waves

Normal QRS Two phases brief phase; depolarization of ventricular septum longer phase; depolarization of both ventricles but the left is larger

First Phase Depolarization of ventricular septum

Second Phase Depolarization of both ventricles but the left is larger

Precordial Leads V 6 V 1

Normal QRS V 6? V 1? Fig. 4 -6 V 1?

Normal QRS V 1 V 6

Normal QRS • Septal r wave • Septal q wave

6. QRS Complex R wave progression

Normal R Wave Progression Transition Zone?

R Wave Progression Transition Zone?

Transition Zone Figure 4 -7

Early & Delayed Transition V 1 V 2 V 3 V 4 • Figure 4 -7 V 5 V 6

6. QRS Complex What is the electrical axis? normal left axis deviation right axis deviation extreme axis deviation

7. St Segment ST segment elevation or depression (see chapters 8 & 9)

8. T Wave Normally positive where QRS wave is positive V 3 - V 6 and II, but negative in a. VR Abnormally tall T waves

Practice ECG Library http: //www. ecglibrary. com/ecghome. html ECG: The Art of Interpretation http: //www. 12 leadecg. com/full/

Normal

Not normal PR interval Mobitz Type II block

Not normal LAD, R wave progression RBB w/inferior MI

Not normal First degree block, left atrial enlargement, left bundle branch block, & inferior MI

Not normal Atrial fibrillation

Normal

Not normal Junctional rhythm

Not normal LAD, late R wave progression Acute MI

Not normal Premature ventricular contractions

Not normal Ventricular tachycardia: note fast rate and wide bizarre QRS.

Normal

Not normal Second degree AV block - type II

Not normal RAD, R wave progression

Not normal Third degree AV block

Not normal Right bundle branch block. Note the wide QRS waves

Normal

Not normal Left bundle branch block. Note the wide QRS waves

a. yes b. vertical c. V 3 d. yes e. yes f. yes

2. No. Although there are P waves, they are negative P waves indicate a retrograde conduction likely coming from the AV junction.