Adel Hasanin, MRCP (UK), MS (Cardiology)

1. ECG Rhythm Recognition Adel Hasanin, MRCP (UK), MS (Cardiology) Adel Hasanin, MRCP (UK)

2. Generation and Conduction of Electrical Current in the Heart Junction Adel Hasanin, MRCP (UK)

3. Electrocardiograph Paper The time is measured horizontally and the voltage is measured vertically. Each 1 second is represented by 5 large boxes (each large box represents 0.2 second) Each large box is divided horizontally into 5 small boxes (each small box represents 0.04 second) Each 1 mV is represented by 2 large boxes (each large box represents 0.5 mV) Each large box is divided vertically into 5 small boxes (each small box represents 0.1 mV) 1 mm = 0.1 mV 1 mV 1mm=0.04 sec 0.5 mV ------0.2 sec ------ 1 second Adel Hasanin, MRCP (UK)

4. ECG Waves and Intervals • Normal P wave = impulse generated at sinus node and conducted through the atrium • Normal PR interval = impulse conducted through the AV node to the ventricle • Normal QRS = impulse generated above the ventricle and conducted through both bundles to the ventricles • ST-T = ventricular repolarization Adel Hasanin, MRCP (UK)

5. PR Interval PR interval Represents the interval from the onset of atrial depolarization to the onset of ventricular depolarization (i.e. The atrial depolarization plus the physiological delay at the AV node). Measured from beginning of the P wave to beginning of the QRS. Normal PR interval = 0.12 – 0.2 sec. (3-5 small boxes) PR Interval Adel Hasanin, MRCP (UK)

6. QRS Complex • QRS complex Represents the simultaneous depolarization of both right and left ventricles • Normal QRS duration≤ 0.11 second (~ 3 small boxes) Adel Hasanin, MRCP (UK)

7. Narrow vs. Wide QRS Complex Normal (narrow) QRS implies: beat arising from above the ventricle (SAN, atrium, or junction) and conducted normally Wide QRS complex implies: Beats arising from the ventricle (PVC, VT, electronic pacemaker) or Beats arising from above the ventricle but abnormally conducted due to BBB or Accessory pathway Adel Hasanin, MRCP (UK)

8. Systematic Rhythm recognition Rhythm analysis implies: Identifying site of impulse formation (sinus, atrium, Junction, ventricle) Identifying the sequence of impulse conduction To identify the heart rhythm, answer the following 5 questions: Are normal P waves present? Is PR interval is normal? Are the QRS complexes narrow or wide? Is the rhythm regular or irregular? Is the HR normal, fast, or slow? Adel Hasanin, MRCP (UK)

9. 1) Are P waves present? P wave is not visible or retrograde, QRS is narrow, rhythm is regular and HR is slow→ junctional rhythm P wave is not visible or retrograde, QRS is narrow, rhythm is regular and HR is normal→ accelerated junctional rhythm P wave is not visible or retrograde, QRS is narrow, rhythm is regular and HR is 100-130→ junctional tachycardia P wave is not visible or retrograde, QRS is narrow, rhythm is regular and HR is 150-250→ SVT Adel Hasanin, MRCP (UK)

10. 1) Are P waves present in normal morphology? Normal P wave before each QRS and normal PR interval, QRS is narrow, rhythm is regular and HR is normal → NSR P waves replaced with saw teeth waves and QRS is narrow → Atrial flutter P waves replaced with fibrillatory waves, QRS is narrow and rhythm is irregular→ AF Adel Hasanin, MRCP (UK)

11. 2) PR interval? PR interval is prolonged, QRS isnarrow and rhythm is regular→ First degree AV block PR is variable with dropped beats , QRS is narrow and rhythm is irregular → 2nd degree mobitz I (wenckebach phenomenon) PR is constant with dropped beats , QRS is narrow and rhythm is irregular→ 2nd degree mobitz II PR is extremely variable, QRS is wide, Rhythm is regular and HR is slow→ 3rd degree AV block Adel Hasanin, MRCP (UK)

12. 3) Are the QRS complexes narrow or wide? Wide QRS regular tachycardia and no visible normal P waves → ventricular tachycardia Wide QRS regular bradycardia, no relation between the P waves and the QRS complexes → complete heart block Wide QRS regular bradycardia and no P waves → idioventricular rhythm Wide QRS rhythm and spike before each QRS → Pacer rhythm Wide QRS complex(es) comes earlier than expected (irregularity) → PVC Adel Hasanin, MRCP (UK)

13. Polymorphic VT (Torsades de pointes) Spindles & Nodes Adel Hasanin, MRCP (UK)

14. 3) Are the QRS complexes narrow or wide? Sinus Tachycardia AF SVT VT Pacemaker Rhythm LBBB Adel Hasanin, MRCP (UK) LBBB

15. RBBB Adel Hasanin, MRCP (UK)

16. Adel Hasanin, MRCP (UK)

17. Ventricular Fibrillation Adel Hasanin, MRCP (UK)

18. 4) Is the rhythm regular or irregular? CHB 2ͦ AV Block Mobitz 1 AF PAC PAC Adel Hasanin, MRCP (UK)

19. 5) Is the HR normal, fast, or slow?...Heart rate can be calculated in 2 ways 1. Divide the constant 300 by the number of large boxes in single cycle (single RR interval) or divide the constant 1500 by the number of small boxes in single cycle 300/4=75 1500/20=75 7x10=70 Adel Hasanin, MRCP (UK) 2. Count cycles (number of RR intervals) in 6 seconds (30 big boxes) and multiply by 10

20. 5) Is the HR normal, fast, or slow? P wave is not visible or retrograde, QRS is narrow, rhythm is regular and HR is slow→ junctional rhythm P wave is not visible or retrograde, QRS is narrow, rhythm is regular and HR is normal→ accelerated junctional rhythm P wave is not visible or retrograde, QRS is narrow, rhythm is regular and HR is 100-130→ junctional tachycardia P wave is not visible or retrograde, QRS is narrow, rhythm is regular and HR is 150-250→ SVT Adel Hasanin, MRCP (UK)

21. 5) Is the HR normal, fast, or slow? Wide QRS regular bradycardia and no P waves →idioventricular rhythm Wide QRS regular rhythm, no P waves and HR is normal →acceleratedidioventricular rhythm Wide QRS regular tachycardia and no visible normal P waves →ventricular tachycardia Adel Hasanin, MRCP (UK)

22. Sinus Bradycardia Adel Hasanin, MRCP (UK)

23. Asystole (Flat Line) Adel Hasanin, MRCP (UK)

24. Adel Hasanin, MRCP (UK)