Steps for Normal Depolarization

1
Steps for Normal Depolarization

• The electrical impulse progress through the
  RBB and LBB and Fascicles simultaneously.
• Depolarization of IVS
• Synchronous Depolarization of RV LV
• Note The electrical activity generated by the
  depolarization of the smaller RV is buried in
  that generated by the LV.

2
(No Transcript)
3
(No Transcript)
4
Depolarization of Septum

• Depolarization of the Interventricular Septum of
  the endocardial to epicardial of the ventricular
  wall is call the Ventricular Activation time
  (VAT) or the Preintrinsicoid Deflection (IDT),
  the duration of the Intrinsicoid Deflection or
  the R peak time.

5
VAT Measurement

• Onset of the QRS complex to the peak of the last
  R wave in the QRS complex.
• Normally less than .04 second in V1 or V2 or less
  than .06 second in V5 and V6.
• RBBB RVH -the VAT is prolonged in leads V1 V2
• LBBB LVH-the VAT is prolonged in Leads V5 V6

6
(No Transcript)
7
(No Transcript)
8
Pathophysiology of the BB and Fascicular Blocks

• Ischemia heart disease
• Acute Mi
• Idiopathic degenerative disease of Conduction
  system
• Cardiomyopathy
• LVH
• Aberrant ventricular conduction
• Miscellaneous causes such as
• Acute or chronic HF, PE, AoValve Disease, Tumors,
  Trauma, Potassium overdose

9
(No Transcript)
10
Right Bundle Branch Block

• The electrical impulses are prevented from
  entering the RV directly because of disruption of
  conduction system.
• RBBB present with intact viable IVS
• RBBB present without intact viable IVS
• ECG characteristics of the two RBBBs differ
  significantly
• Compare Leads 1 V1, V6

11
RBBB

• Impulses travel down the LBB in to the IS
  LV-(Normal)
• IS to right to enter the RV after a short delay
• LV depolarize in normal way first the septum
  from left to right
• Then the LV from right to left
• LV depolarization
• RV depolarizes in a normal direction
• Delay results in a wide bizarre shape/appearance
• .12 seconds or greater (complete)
• .10 and .11 seconds (incomplete)