• Ventricular Tachycardia
• Basic Classification
• Monomorphic Ventricular Tachycardia
• Re-entry and Ventricular Scar
• ECG and Monomorphic Ventricular Tachycardia
• Wide-Complex Tachycardia

Ventricular Tachycardia

• Ventricular tachycardia (VT) has a ventricular ectopic focus
• below the His bundle
• The focus generates impulses with a rate > 100/min.
• The mechanism of impulses can be:
• Re-entry (most common)
• Increased automaticity
• Trigger activity
• Wide QRS complexes (>0.12s) occur
• Rarely, QRS are narrow (VT from the area of the ventricular septum, Fascicular VT)

Monomorphic Ventricular Tachycardia

• It is the most common VT
• It occurs in a structurally damaged heart
• Most often it is due to a scar in the ventricle after a myocardial infarction
• A reentry occurs in the scar
• And generates impulses with a rate > 100/min.
  
  
• All QRS complexes are monomorphic (identical)
• Therefore, it is referred to as monomorphic

Re-entry and Ventricular Scar

• Monomorphic VT most commonly arises due to re-entry in a scar
• Re-entry in the scar most often has the shape of a figure-eight (8)
• The circling impulse is triggered by a timed
• ventricular extrasystole (VES), rarely atrial extrasystole
• Entrance
• It is the point of entry for VES into the re-entry
• VES must enter the Entrance outside
• the refractory period
• VES then triggers the circling impulse
• Exit site
• It is the point of exit for the impulse from the re-entry
• From the exit site begins the ventricular vector
• which creates the wide QRS (> 0.12s)
• Isthmus is the area of slow conduction in the re-entry

Wide-Complex Tachycardia

• Every VT, including monomorphic VT, is a wide-complex tachycardia (WCT)
• Wide-complex tachycardia is defined as:
• Tachycardia (frequency > 100/min.)
• With wide QRS complexes (≥ 0.12s)

• Wide-complex tachycardia can have 3 causes:
• Ventricular tachycardia (accounts for 80% of wide-complex tachycardias)
• The ventricles are depolarized from a ventricular ectopic focus
• which is located somewhere below the bifurcation of the bundle branches
• Supraventricular tachycardia with aberrant conduction
• The ventricles are depolarized only through one bundle branch
• The patient has a pre-existing or functional bundle branch block
• Supraventricular tachycardia with an accessory pathway (Antidromic AVRT)
• In WPW syndrome, the ventricles and atria are connected through two points (AV junction and an accessory pathway)
• If an impulse starts circulating between the atria and ventricles (reentry), an antidromic AVRT arises
• The ventricles are depolarized through the accessory pathway via the myocardium, not through the conduction system
• Rare causes of wide-complex tachycardia:
• Severe mineral imbalance (hyperkalemia)
• Intoxication with sodium channel blockers
• Pacemaker tachycardia

Monomorphic Ventricular Tachycardia

• All QRS complexes are wide and uniform
• Signs of ventricular tachycardia:
• Wide QRS complexes 0.2s
• Positive precordial concordance (V1-V6)
• Brugada sign
• RS interval > 100ms (aVR, aVL)
• In the second half of the EKG, there is ventricular bigeminy
• Alternating capture beats and ventricular extrasystoles
• R (Q) wave interval in lead II > 50ms

Monomorphic Ventricular Tachycardia

• All QRS complexes are wide and uniform
• Signs of ventricular tachycardia:
• Frequency 150/min.
• Wide QRS complexes 0.2s
• Josephson's sign
• Notch on the descending part of the S wave (III)
• Extreme right axis deviation (180° to -90°)
• Negative QRS (I, aVF)

Monomorphic Ventricular Tachycardia

• All QRS complexes are wide and uniform
• Signs of ventricular tachycardia:
• Frequency 180/min.
• Wide QRS complexes 0.18s
• Extreme right axis deviation (180° to -90°)
• Negative QRS (I, aVF)
• In V1, there is a monophasic R wave
• In V6, there is an rS configuration
• Small r wave and large S wave