2. Conduction Disturbances

3. Sinus bradycardia sinus tachycardia… sinus dysrhythmia (arhythmia) sinus pause (arrest) sinoatrial block
Only single shape P

4. SINUS DYSRHYTHMIA
Some variation in the sinus node discharge rate is common, but if the variation exceeds 0.12 s between the longest and shortest intervals, sinus dysrhythmia is present.
The ECG:
(1) normal sinus P waves and P-R intervals, (2) 1:1 AV conduction, and
(3) variation of at least 0.12 s between the shortest and longest P-P interval

7. Sinus Arrhythmia

8. Sinus dysrhythmia:(note slight irregularity).

9. Sinus Arrest (Pause)
Sinus pause is a failure of impulse formation within the sinus node.
In sinus arrest, the P-P interval has no mathematical relation to the basic sinus node discharge rate

11. s. dysrhythmia vs s. arrest?
Sinus dysrhythmia : irregular-irregular
Sinus Arrest (Pause): regular-irregular

12. The pause is not equal to exactly two or more)3,4,…) cardiac cycles of the underlying rhythm.

13. Sinoatrial Block

14. In a sinus exit block the pause is equal to exactly
two or more cardiac cycles of the underlying
rhythm.
The electrical impulse from the SA node is blocked
and not conducted to the atria.

15. Sino Atrial Exit Block
Implies that there is delay or failure of a normally generated sinus impulse to exit the nodal region.
First degree SA block:slowed conduction
Second degree SA block:intermittent conduction
1.Type 1 (Mobitz 1) Type 2 (Mobitz 2)
Third degree SA block: complete conduction failure

16. First Degree Sino Atrial Exit Block
Implies that the conduction time where each impulse leaving the node is prolonged
This problem cannot be observed on surface EKG
Electro physiology study needed to measure the sino atrial conduction time

17. Second Degree Sino Atrial Exit Block
Type I (SA Wenckebach)
1.PP intervals gradually shorten until a pause occurs (i.e., the blocked sinus impulse fails to reach the atria)
2.The pause duration is less than the two preceding PP intervals
3.The PP interval following the pause is greater than the PP interval just before the pause

18. SA Wenckebach
X Y Z
X>Y
Z<2X
Z<2Y

19. SA Block type1 vs S. Pause? Both irregular-irregular SA Block type1:
1.PP intervals gradually shorten until a pause occurs
2.The pause duration is <2 PP
3.The PP interval following the pause > PP interval just before the pause

21. Second Degree Type II SA Block
PP intervals fairly constant (unless sinus arrhythmia present) until conduction failure occurs.
The pause is approximately twice the basic PP interval

23. Third Degree Or Complete Sino Atrial Exit Block
May Cannot be distinguished from a prolonged sinus pause or arrest
According to below foci or escape rhythm ECG is variable!
Can be identified from direct recording of sinus node pacemaker activity during an EP study

24. Rosen Sinoatrial Block and Escape Rhythms
Incomplete SA block is diagnosed when an occasional P wave is dropped from the normal P-QRS-T sequence on the ECG. There are no P waves on the ECG
complete SA block (sinus arrest).
Usually, a lower pacemaker emerges in complete SA block; if this pacemaker is within the AV node, the QRS complex is narrow and results in an "idiojunctional“escape rhythm at a rate of 45 to 60 beats/min.

26. SA Block type2 vs SA arrest?
Both regular-irregular
PP’ = 2 x PP >>> SA Block type2

27. The pause is not equal to exactly two or more)3,4,…) cardiac cycles of the underlying rhythm.

30. Dx Regular-Irregular Or Irregular-Irregular
Regular-Irregular: SA Block type2 or SA arrest
PP’ = 2 x PP >>> SA Block type2
Irregular-Irregular: SA Block type1 vs S. arrhythmia

31. Sick Sinus Syndrome All result in bradycardia
Sinus bradycardia (rate of ~43 bpm) with a sinus pause
Often result of tachy-brady syndrome: where a burst of atrial tachycardia (such as afib) is then followed by a long, symptomatic sinus pause/arrest, with no breakthrough junctional rhythm.

32. SSS

33. Sick sinus syndrome is an indication for a permanent pacemaker
Sick sinus syndrome is an indication for a permanent pacemaker. Pharmacologic treatment of atrial tachyarrhythmias carries the risk of aggravating preexisting AV block or sinus arrest.
Therefore, most patients should have pacemaker implantation before drug therapy is begun.

34. Only single shape P

35. Atrial Dysrhythmias
Atrial dysrhythmias have ECG features similar to those of sinus dysrhythmias,
except
an atrial source serves as the pacemaker, producing P' waves that are different from the sinus P waves.
The P'R interval may also vary from the normal sinus PR interval, which distinguishes these rhythms.

36. PAC
non-compensatory pause
MAC
Wandering pacemaker

37. MAT

38. AV Blocks: Divided in to incomplete and complete block
Incomplete AV block includes
a. first-degree AV block
b. second degree AV block
c. advanced AV block
Complete AV block,also known as third degree AV block

39. Location of the Block
Proximal to, in, or distal to the His bundle in the atrium or AV node
All degrees of AV blocks may be intermittent or persistent

40. First Degree AV Block
PR interval is prolonged seconds, but no R-R interval change
Normal=0.10”-0,20”

43. Second-Degree AV Block
There is intermittent failure of the supraventricular impulse to be conducted to the ventricles
Some of the P waves are not followed by a QRS complex.The conduction ratio (P/QRS ratio) may be set at 2:1,3:1,3:2,4:3,and so forth

44. Types Of Second-Degree AV Block:I and II
Type I also is called Wenckebach
phenomenon or Mobitz type I and represents the more common type
Type II is also called Mobitz type II

45. Type I Second-Degree AV Block: Wenckebach Phenomenon
ECG findings
1.Progressive lengthening of the PR interval until a P wave is blocked
2.Progressive shortening of the RR interval until a P wave is blocked
3.RR interval containing the blocked P wave is shorter than the sum of two PP intervals

47. Type II Second-Degree AV Block: Mobitz Type II
ECG findings
1.Intermittent blocked P waves
2.PR intervals may be normal or prolonged,but they remain constant
3.When the AV conduction ratio is 2:1,it is often impossible to determine whether the second-degree AV block is type I or II
4. A long rhythm strip may help

50. High-Grade or Advanced AV Block
When the AV conduction ratio is 3:1 or higher,the rhythm is called advanced AV blocked
A comparison of the PR intervals of the occasional captured complexes may provide a clue
If the PR interval varies and its duration is inversely related to the interval between the P wave and its preceding R wave (RP), type I block is likely
A constant PR interval in all captured complexes suggests type II block

53. Complete (Third-Degree) AV Block
There is complete failure of the supraventricular impulses to reach the ventricles
The atrial and ventricular activities are independent of each other

54. ECG Findings
In patients with sinus rhythm and complete AV block, the PP and RR intervals are regular, but the P waves bear no constant relation to the QRS complexes

57. Bundle Branch Block Left Bundle Branch Block 1.Complete LBBB
2.Incomplete LBBB
Rigt Bundle Branch Block
1.Complete RBBB
2.Incomplete RBBB

58. Left Bundle Branch Block Criteria
1.The QRS duration is > 120 ms
2.Leads V5,V6 and AVL show broad and notched or slurred R waves
3.With the possible exception of lead AVL, the Q wave is absent in left-sided leads
4.Reciprocal changes in V1 and V2
5.Left axis deviation may be present
Deep S in V1 no R inV1 &
R in V6 no S in V6

62. Right Bundle Branch Block
The diagnostic criteria include
1.QRS duration is >120 ms
2.An rsr’,rsR’ or rSR’ pattern in lead V1 or V2 and occasionally a wide and notched R wave.
3.Reciprocal changes in V5,V6,I and AVL

66. Incomplete RBBB
Criteria for incomplete RBBB are the same as for complete RBBB except that the QRS duration is < 120 ms

67. IRBBB

68. interventricular conduction delay IVCD
Nonspecific Intraventricular Conduction Defects (IVCD) QRS duration >0.10s indicating slowed conduction in the ventricles Criteria for specific bundle branch or fascicular blocks not met

72. bilateral bundle branch block (BBBB) interruption of cardiac impulses through both bundle branches, clinically indistinguishable from third degree (complete) heart block.

73. Fascicular Blocks The left bundle branch divides into two fascicles
1.Superior and anterior
2.Inferior and posterior

74. Types Of Fascicular Block
Left anterior fascicular block
Left posterior fascicular block
Bifascicular Block
Trifascicular Block

76. Left Anterior Fascicular Block
Left axis deviation , usually -45 to -90 degrees
QRS duration usually <0.12s unless coexisting RBBB
Poor R wave progression in leads V1-V3 and deeper S waves in leads V5 and V6
There is RS pattern with R wave in lead II > III
S wave in lead III > lead II
QR pattern in lead I and AVL,with small Q wave
No other causes of left axis deviation

77. LAFB

78. LAFB

79. LAFB

80. Left Posterior Fascicular Block
Diagnostic Criteria include
1.QRS duration <120 ms
2.No ST segment or T wave changes
3.Right axis deviation (100 degree)
4.QR pattern in inferior leads (II,III,AVF) small q wave
5.RS patter in lead lead I and AVL(small R with deep S)
6.No other causes of right axis deviation

83. LPFB

84. Bifascicular Bundle Branch Block
RBBB + LAFB
RBBB + LPFB
LBBB
LAFB + 1st degree AV
LPFB + 1st degree AV

85. RBBB+ LAFB

86. ?

87. RBBB + LPFB

88. ?

89. Trifascicular Block LBBB + 1st degree AV
RBBB + LAFB/LPBF +1st degree AV

90. Trifascicular RBBB+ LAFB + 1st degree

91. ?

92. RBBB +LAFB +1st degree

93. Indications For Implantation of Permanent Pacing in Acquired AV Block
Class I
1.Third-degree AV block associated with
a.Bradycardia with symptoms (C)
b.Arrhythmias and other medical conditions that require drugs that result in symptomatic bradycardia(C)
c.Asystole>/-3.0 seconds or any escape rate<40bpm awake, symptom free Pt (B,C)
d.After catheter ablation of the AV junction (B,C)
e.Neuromuscular diseases with AV block (Myotonic muscular dystrophy)
2.Second-degree AV block with symptomatic bradycardia

94. Class IIa
Asymptomatic third-degree AV block with average awake ventricular rates of 40 bpm or faster (B,C)
Asymptomatic type II second-degree AV block (B)
First-degree AV block with symptoms suggestive of pacemaker syndrome and documented alleviation of symptoms with temporary AV pacing (B)

95. Class IIb
Marked first-degree AV block (>0.30 second) in patients with LV dysfunction and symptoms of congestive heart failure in whom a shorter AV interval results in hemodynamic improvement, presumably by decreasing left atrial filling pressure (C)

96. Class III Asymptomatic first-degree AV block (B)
Asymptomatic type I second-degree AV block at the supra-His (AV node) level or not known to be intra- or infra-Hisian (B, C)
AV block expected to resolve and unlikely to recur (eg,drug toxicity, Lyme disease) (B)

97. Indications for Permanent Pacing in Chronic Bifascicular and Trifascicular Block
1.Class I
Intermittent third-degree AV block. (B)
Type II second-degree AV block. (B)
2.Class IIa
Syncope not proved to be due to AV block when other likely causes have been excluded, specifically ventricular tachycardia (VT). (B)
3.Class III
Fascicular block without AV block or symptoms. (B)
Fascicular block with first-degree AV block without symptoms. (B)

98. Indications for Permanent Pacing After The Acute Phase Of Myocardial Infarction
Class I
Persistent second-degree AV block with bilateral bundle branch block or third-degree AV block within or below the His-Purkinje system after AMI. (B)
Transient advanced (second- or third-degree) infranodal AV block with bundle branch block. (B)
Persistent and symptomatic second- or third-degree AV block. (C)

99. Indications Of Permanent Pacing After the Acute Phase Of Myocardial Infarction (Continuation)
Class IIb
Persistent second- or third-degree AV block at the AV node level. (B)
Class III
Transient AV block in the absence of intraventricular conduction defects. (B)
Transient AV block in the presence of isolated left anterior fascicular block. (B)
Acquired left anterior fascicular block in the absence of AV block. (B)
Persistent first-degree AV block in the presence of bundle branch block that is old or age indeterminate. (B)

103. Atropine will likely be ineffective in patients who have undergone cardiac transplantation because the transplanted heart lacks vagal innervation.

105. Tintinalli
As patients with atrial fibrillation can have a physiologic rate response to trauma, sepsis, and other disease process, other causes of hypotension should be investigated before concluding that the rate is causing the hemodynamic deterioration.

108. Epinephrine 2-10 micg/min
Dopamine 2-10 micg/kg/min
Norepinephrine 2-10 mic/min
Dobutamine 2-10 mic/kg/min
Nitroglycerine 5-10micg/min
Nitroprosside mic/kg/min