This document discusses Dr. Md.Toufiqur Rahman's credentials as an Associate Professor of Cardiology and then provides examples of different types of conduction tissue pathology in electrocardiograms (ECGs), including sinoatrial block, first degree block, second degree block (Mobitz type 2 and Wenckebach), second degree block (2:1), and complete (third degree) block. Diagrams of ECG tracings are shown to illustrate each type of block.

1. Dr. Md.Toufiqur Rahman
MBBS, FCPS, MD, FACC, FESC, FRCP,
FSCAI, FAPSIC, FAPSC
Associate Professor of Cardiology
National Institute of Cardiovascular Diseases
Sher-e-Bangla Nagar, Dhaka-1207

2. Dr. Md.Toufiqur Rahman
MBBS, FCPS, MD,FACC, FESC, FRCP, FSCAI, FAPSIC, FAPSC

3. Conduction Tissue

4. Normal Rhythm ECG

5. Leads of ECG

6. Precordial Leads

7. Pathology of conduction tissue

8. Sinoatrial block
• Sinus rhythm for three beats, then a 'sinus pause'
• P waves arrowed
• The expected P wave is not seen, but the SA node must have been
depolarized because the next P wave appears at the predicted time

9. First degree block
• Sinus rhythm
• PR interval is constant (360 ms)

10. Second degree block (Mobitz type 2)
• Sinus rhythm with a normal PR interval
• One P wave (arrowed) is not followed by a QRS
complex

11. Second degree block (Wenckebach)
• Three beats with progressively longer PR intervals are
followed by a non-conducted P wave (arrowed)
• The next PR interval is short, but this is followed by a longer
PR interval and then another non-conducted beat

12. Second degree block (2:1)
• The conducted beats have a normal PR
interval
• Alternate P waves are not followed by a QRS
complex
;

13. Complete (third degree) block
• No relationship between P waves (arrowed) and QRS
complexes
• The QRS complexes are normal, indicating that the origin
of ventricular depolarization is within the His bundle
• The ventricular rate is 30/min

14. Complete (third Degree) block
• No relationship between P waves (arrowed) and QRS
complexes
• Wide QRS complexes
• Ventricular rate of 22/min

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