ECG characteristics of LVOT VT


  RBBB (right bundle branch block) morphology with an inferior axis.

  The precordial R-wave transition occurs
at or before lead V3 (earlier than RVOT-VT).

     
- VT originating from the left coronary cusp has an earlier R-wave transition (typically by V1/2)

        than the right coronary cusp (V2/3).

     
- A broader R-wave duration (0.5 ms) and a taller R/S-wave amplitude in V1 and V2 favor

        aortic cusp location.

  Notched qrS in V1 or V2.

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References

  Curr Probl Cardiol 2013;38:131-158.

  J Am Coll Cardiol 2002;39:500-508.

  J Am Coll Cardiol 2011;57:2255-62





ECG 1. The ECG above belongs to a 63 years-old man with a normal ECHOcardiogram (no structural heart disease).

Comment by Dr. Fred Kusumoto:
This VT originates from the LVOT. This is why RBBB pattern in lead V1.
The LVOT is "behind" the RVOT so ventricular activation proceeds from posterior to anterior.
The relatively narrow QRS in this 63 years-old man suggests that it is on the septal portion of the LVOT and thus
engages the His Purkinje system relatively early.
Anatomically this area is adjacent to the posterior wall of the RVOT. From the RVOT there would be LBBB morphology in V1
but with an earlier precordial transition than more anterior portions of the RVOT)

Click here for a more detailed ECG





ECG 2. The ECG above belongs to an 80 years-old man with a normal ECHOcardiogram.
VPCs show inferior axis and right bundle branch block morphology.

Comment by Dr. Fred Kusumoto:
VPCs probably arise from the LVOT region.
One suspects that the VPCs come from the anterolateral portion of the outflow tract or perhaps
even more anterior involving the mitral annulus. However, it can often be difficult to be too localize exactly
because of variability in LV orientation, lead placement, etc.

Click here for a more detailed ECG





ECG 3. The ECG above belongs to a 20 years-old woman. She is also a 4 months-old pregnant.
The basic rhythm is sinus rhythm with right bundle branch block.
There are also frequent VPCs with inferior axis and right bundle branch block morphology.

Comment by Dr. Fred Kusumoto:
VPCs probably arise from the LVOT region.

Click here for a more detailed ECG