1. ECG Conduction Abnormalities

2. Schematic of the cardiac conduction system

3. Conduction Abnormalities
Heart block can occur anywhere in the specialized conduction system beginning with the sino-atrial connections, the AV junction, the bundle branches and their fascicles, and ending in the distal ventricular Purkinje fibers.

4. Conduction Abnormalities
Sinus Block
AV block
Bundel Branch Block

5. Conduction Abnormalities
Disorders of conduction may manifest as slowed conduction (1st degree), intermittent conduction failure (2nd degree), or complete conduction failure (3rd degree).
In addition, 2nd degree heart block occurs in two varieties:
Type I (Wenckebach) -Type I block there is decremental conduction which means that conduction velocity progressively slows down until failure of conduction occurs.
Type II (Mobitz). In Type II block is all or none.

6. Sino-Atrial Exit Block (SA Block)
2nd Degree SA Block: this is the only degree of SA block that can be recognized on the surface ECG (i.e., intermittent conduction failure between the sinus node and the right atrium).
There are two type.

7. Sino-Atrial Exit Block (SA Block)
Type I (SA Wenckebach): the following 3 rules represent the classic rules of Wenckebach, which were originally described for Type I AV block.
The rules are the result of decremental conduction where the increment in conduction delay for each subsequent impulse gets smaller until conduction failure finally occurs:
PP intervals gradually shorten until a pause occurs (i.e., the blocked sinus impulse fails to reach the atria)
The pause duration is less than the two preceding PP intervals
The PP interval following the pause is greater than the PP interval just before the pause

8. Sino-Atrial Exit Block (SA Block)
I type- Wenckebach
1. The interval R - R is gradually shortened.
2. A pause SA blockade less than the doubled duration of a previous complex.
3. The interval R - R after a pause is longer than an interval R - R before SA a pause.

10. Sino-Atrial Exit Block (SA Block)
Type II SA Block (Mobitz) :
 PP intervals fairly constant (unless sinus arrhythmia present) until
conduction failure occurs.
 The pause is approximately twice the basic PP interval

12. Various variants of localisation of Av-blockade
1 - atrial proximal type
2 - AV node proximal type
3 – tube A-V block distal type
4 – distal three bundle AV block

13. INCOMPLETE А-V BLOC
First-degree AV block
1. Lengthening of interval Р-Q> 0,20 seconds
2. Complex QRS is not changed
3.Type I AV block is almost always located in the AV node, which means that the QRS duration is usually narrow, unless there is preexisting bundle branch disease

14. First-degree AV block node type

15. II degrees A-V bloc I type-with Venkebaha-Samoilov's periods (I)
1. Progressing lengthening of interval РQ and loss of a complex QRST
2. Complex QRS is not changed
3. After a long pause the least interval РQ is observed

16. Atrio-Ventricular (AV) Block

17. Mobitz type I second-degree AV block 3:2 The arrow specifies loss ventricular complex

18. Mobitz type I second-degree AV block
The PR interval prolongs prior to the pause as shown in
the ladder diagram. The ECG pattern results from
slowing of conduction in the AV node

19. Mobitz type II second-degree AV block
1. There is no progressing lengthening of interval РQ before loss a complex (QRST)
2. Complex QRS is not changed.
3. Duration of a long pause is equal to the sum of 2 usual intervals Р-Р (R-R) or is a little bit shorter than it.

20. Mobitz type II second-degree AV block with presence constant normal (upper) or increased (down) interval P-Q (R)

21. Complete (3rd Degree) AV Block
Usually see complete AV dissociation because the atria and ventricles are each controlled by separate pacemakers.
Narrow QRS rhythm suggests a junctional escape focus for the ventricles with block above the pacemaker focus, usually in the AV node.
Wide QRS rhythm suggests a ventricular escape focus (i.e., idioventricular rhythm).
The location of the block may be in the AV junction or bilaterally in the bundle branches.

22. Complete (3rd Degree) AV Block
I type – proximal type
1. Complex QRS is not changed
2. Distance R-R are equal each other
3. Full and - in dissociation, i.e. an atrial and ventricular go in the rate
4. HR of ventricular > 40 in a minute

23. Proximal type Complete AV Block

24. Complete (3rd Degree) AV Block
II type - distal
1. Distance R-R are equal each other
2. Complex QRS is changed, wide > 0,12 seconds
3. Frequency of reductions ventricular <40 in a minute

25. Distal type Complete AV Block

26. High-grade AV block AV block that is intermediate between second
and third degree is referred to as high-grade
AV block
1. The number of Р wave is more than quantity of complexes QRS
2. It is observed two or more «the blocked wave» Р after which does not follow complex QRS
3. Complex QRS is not changed

27. High-grade AV block

28. Every-other QRS to be blocked causing a 2:1

29. SYNDROME FREDERIC A combination complete А-V blockade and
Atrial fibrillation or atrial flutter
1. Tooth Р is absent
2. Blinking waves (f) or tremblings (F) auricles
3. Frequency of reductions ventricular bpm
4. Ventricular rhythm is correct, distance R-R are equally equal

30. SYNDROME FREDERIC

31. WOLFF - PARKINSON - WHITE SYNDROME (WPW)
PRESENCE OF THE ADDITIONAL BUNCH OF KENT
1. Complex QRS is widened> 0,12 seconds
2. Delta-wave
3. Interval Р-Q is shortened (<0,12 seconds)

32. WPW
TYPE A
1. Delta- wave and complex QRS in the right and left chest assignments it is directed upwards

33. ECG WPW Type A

34. WPW
TYPE B
1. Delta-wave and complex QRS in the right chest assignments it is directed from top to bottom.
2. In I, V5, V6 delta - wave and complex QRS it is directed upwards.

35. ECG WPW TYPE B

36. SYNDROME СLС
PRESENCE OF THE BUNCH OF JAMES (The additional bunch connecting a final part A-V of node or an initial part of bunch His)
1. Interval Р-Q is shortened
2. Complex QRS is not changed.

37. SYNDROME СLС

38. Comparison of typical QRS-T patterns in right bundle branch block (RBBB) and left bundle branch block (LBBB) with the normal pattern in leads V1 and V6.
Note the secondary T-wave inversions (arrows) in leads with an rSR' complex with RBBB and in leads with a wide R wave with LBBB.

39. ECG signs of complete LBBB
1. Complex QRS is widened > 0,12 sec
2. In leads V5, V6, wide R wave (without Q and S) reminds the M letter
3. Time of an internal deviation in leads V5, V6> 0,08 sec
4. In leads V1, V2 wide, deep S wave
5. Displacement of segment S-Т downwards, negative Т wave in leads V5, V6.
6. Discordant wave between the extreme right and left chest leads.

40. Complete LBBB

41. Left Bundle Branch Block (LBBB)
"Complete" LBBB" has a QRS duration >0.12s
Close examination of QRS complex in various leads reveals that the terminal forces (i.e., 2nd half of QRS) are oriented leftward and posteriorly because the left ventricle is depolarized after the right ventricle.
Terminal S waves in lead V1 indicating late posterior forces
Terminal R waves in lead I, aVL, V6 indicating late leftward forces;
The "normal" ST-T waves in LBBB should be oriented opposite to the direction of the terminal QRS forces; i.e., in leads with terminal R or R' forces the ST-T should be downwards; in leads with terminal S forces the ST-T should be upwards.

42. Left Anterior Fascicular Block (LAFB)
Left axis deviation in frontal plane, usually -45o to -90o rS complexes in leads II, III, aVF
Small q-wave in leads I and/or aVL
R-peak time in lead aVL >0.04s, often with slurred R wave downstroke
QRS duration usually <0.12s unless coexisting RBBB
Usually see poor R progression in leads V1-V3 and deeper S waves in leads V5 and V6
May mimic LVH voltage in lead aVL, and mask LVH voltage in leads V5 and V6.

43. Left Anterior Fascicular Block (LAFB)

44. Left Posterior Fascicular Block (LPFB)
Very rare intraventricular defect!
Right axis deviation in the frontal plane (usually > +100o)
rS complex in lead I
qR complexes in leads II, III, aVF, with R in lead III > R in lead II
QRS duration usually <0.12s unless coexisting RBBB

45. Left Posterior Fascicular Block (LPFB)

46. Right Bundle Branch Block (RBBB)
"Incomplete" RBBB has a QRS duration of s with the same terminal QRS features. This is often a normal variant.
The "normal" ST-T waves in RBBB should be oriented opposite to the direction of the terminal QRS forces;
in leads with terminal R or R' forces the ST-T should be negative or downwards;
in leads with terminal S forces the ST-T should be positive or upwards.

47. ECG signs of complete RBBB
1. ORS is widened, deformed> 0,12 seconds
2. In leads V1, V2 the complex is split in shape rSR, rSR, RSR
3. Time of an internal deviation in assignments V1, V2> 0,06 sec.
4. Displacement of segment S-T downwards and negative Т wave in leads V1, V2,
5. In leads V5, V6 wide S wave.

48. Complete RBBB