This type of ventricular tachycardia (VT) is also called as Belhassen type VT

      since Belhassen et al. first reported that it was sensitive to
Verapamil .



Etiology

  This is a type of idiopathic VT originating from the left ventricle (LV).

 
Reentry is the mechanism of this tachycardia.

  Generally occurs at rest, but exercise or emotional stress may also trigger this VT.




Diagnostic criteria

  Morphology of the VT is right bundle branch block (RBBB) and left axis deviation.

  When there is no VT, the basal ECG is generally normal.

  In some patients, ECG recorded after the fascicular VT attack may show T wave negativity

      (
T wave memory ).

  These patients usually do not have any accompanying cardiac diseases.

  Unlike the more common ischemic VT, fascicular VT does not respond to lidocaine.




Classification of Fascicular VTs according to the point of origin

  Left posterior fascicular VT (LPF VT)

  Left anterior fascicular VT (LAF VT)

  Left upper septal VT (septal VT)




Clinical significance

  During a fascicular VT attack, the patient usually complains of palpitation, fatique, dizziness or dyspnea.

  Syncope or sudden cardiac death is very rare.

  Since the QRS complex is not so wide, fascicular VT may be easily mistaken for

      supraventricular tachycardia (SVT).

  Unlike SVT, fascicular VT does not respond to adenosine or vagal maneuvers.

  Unlike the common ischemic VT, fascicular VT does not respond to lidocain.

 
Atrial or ventricular pacing may initiate this tachycardia.

  Generally occurs at rest. Exercise or emotional stress may also trigger this arryhthmia.




References

  Br Heart J 1981;46:679-682.

  Am Heart J 1994;128:147-156.

  Circulation 1990;82:1561-1573.

  Am J Emerg Med 2007;25:572-575.





ECG 1a. The basal ECG of the patient is seen above. No ventricular tachycardia (VT).

Prof. Dr. Bernard Belhassen has donated the above ECG to our website.

Click here for a more detailed ECG




ECG 1b. The same patient's ECG during fascicular VT showed right bundle branch block (RBBB) and left axis deviation.

Prof. Dr. Bernard Belhassen has donated the above ECG to our website.

Click here for a more detailed ECG




ECG 1c. Pacing from right ventricular apex in the same patient induced VT with RBBB morphology and right axis deviation.

Prof. Dr. Bernard Belhassen has donated the above ECG to our website.

Click here for a more detailed ECG




ECG 1d.

Prof. Dr. Bernard Belhassen has donated the above ECG to our website.

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ECG 1e. Left ventricular pacing in the same patient resulted in a VT attack with RBBB and right axis deviation.

Prof. Dr. Bernard Belhassen has donated the above ECG to our website.

Click here for a more detailed ECG




ECG 1f. Final ECG after a total of 6 RF (radiofrequency) pulses shows that the VT attack is terminated.

Prof. Dr. Bernard Belhassen has donated the above ECG to our website.

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ECG 2a. Above is an ECG from a patient with Belhassen type VT (verapamil-sensitive VT, fascicular VT). Limb leads are seen.
The ECG is recorded at a paper speed of 50mm/second.

Dr. Peter Kukla has donated the above ECG to our website.

Click here for a more detailed ECG




ECG 2b. The same patient's chest leads are seen above. The above ECG is recorded at a paper speed of 50 mm/second.

Dr. Peter Kukla has donated the above ECG to our website.

Click here for a more detailed ECG




ECG 2c. The same patient's ECG after fascicular VT has been terminated.
The T wave negativity in inferior leads and C4-to-C6 denote to T wave memory effect.

Dr. Peter Kukla has donated the above ECG to our website.

Click here for a more detailed ECG