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Idiopathic Ventricular Tachycardia

Idiopathic ventricular tachycardia

Ventricular Tachycardia
Idiopathic Ventricular Tachycardia
Ventricular Tachycardias from Outflow Tracts
Ventricular Tachycardia from the Right Ventricular Outflow Tract
Ventricular Tachycardia from the Left Ventricular Outflow Tract
Fascicular Ventricular Tachycardia

Ventricular Tachycardia

Ventricular Tachycardia (VT) originates from a ventricular ectopic focus

Below the His bundle

The focus generates impulses with a frequency > 100/min.

The mechanism of impulses can be:

Re-entry (most common)
Increased automaticity
Trigger activity

VT results in wide QRS complexes (>0.12s)

Rarely, QRS complexes are narrow (<0.12s):
- VT from the ventricular septum area
- Fascicular ventricular tachycardia

VT consists of at least 3 consecutive ventricular beats

If fewer, it is ventricular extrasystoles

VT almost always occurs in a structurally damaged heart

Most commonly in a scar after an myocardial infarction

Idiopathic Ventricular Tachycardia

idiopathic monomorphic ventricular tachycardia, RVOT-VT, LVOT-VT, Fascicular VT

Idiopathic VT occurs in a structurally normal heart

(even without electrolyte disturbances or a prolonged QT interval)
10% of VT cases are idiopathic
90% of VT occurs in a structurally damaged heart

In idiopathic VT, an ectopic focus arises in the region of:

Ventricular outflow tracts
Fascicles of the left Tawar bundle

We recognize 3 types of idiopathic ventricular tachycardia

Ventricular Tachycardias from Outflow Tracts

VT in the context of arrhythmogenic right ventricular dysplasia in the outflow tract area

It is not idiopathic VT, because it involves a structurally altered right ventricle (including the outflow tract)

Ventricular tachycardias from the outflow tract are mostly idiopathic
There are 2 idiopathic VT from the outflow tract:

The mechanism is triggered activity
They respond well to adenosine, and are therefore often referred to as adenosine-sensitive VT

Ventricular tachycardia from arrhythmogenic right ventricular dysplasia does not respond to adenosine

Ventricular outflow tachycardias are

90% non-sustained monomorphic VT

Sometimes only numerous ventricular extrasystoles without VT are present
Extrasystoles occur at rest and disappear with physical exertion

10% sustained monomorphic VT

They occur during physical exertion

Ventricular Tachycardia from the Right Ventricular Outflow Tract

Right Ventricular Outflow Tract (RVOT) Tachycardia (Monomorphic VT)

Right Ventricular Outflow Tract (RVOT) Tachycardia
Ventricular Tachycardia from the Right Ventricular Outflow Tract
It is the most common idiopathic VT

Accounts for 70% of all idiopathic VTs

Occurs in young individuals aged 20-50 years
Triggered by physical or emotional stress
The main vector points downwards towards the left ventricle
On ECG:

Shape of left bundle branch block
Positive QRS in inferior leads (II, III, aVF)
Transition zone > V2

ECG Right ventricular outflow tract (RVOT) ventricular tachycardia, Inferior axis, AV dissociation

Ventricular Tachycardia from the Right Ventricular Outflow Tract

Frequency: 160/min.
Wide QRS complexes (>0.12s)
Transition Zone (V3)
- The position of the transition zone differentiates VT from the right and left outflow tracts
Pattern of left bundle branch block
- Wide QRS complexes
- Deep S in V1
- Dominant R in V6
Vertical Axis (+ 90°)
- Positive QRS in II, III, aVF
AV Dissociation
- P waves visible in continuous lead II, deforming the QRS complexes
- AV dissociation is a fundamental sign of ventricular tachycardia

Ventricular Tachycardia from the Left Ventricular Outflow Tract

Idiopathic Left Ventricular Outflow Tract (LVOT) Tachycardia

Left Ventricular Outflow Tract (LVOT) Tachycardia
Ventricular Tachycardia from the Left Ventricular Outflow Tract
Accounts for 20% of idiopathic VTs
Common sites of origin:

Aortic root near the origin of the coronary arteries (Valsalva sinus)
Basal part of the left ventricle
Epicardium of the left ventricular outflow tract

Main vector points downwards towards the left ventricle

Does not point towards the right ventricle because the left ventricle is more massive

On the ECG, it resembles the pattern of VT from the right ventricular outflow tract:

Pattern of left bundle branch block
Positive QRS in inferior leads (II, III, aVF)
VT from the left ventricular outflow tract has additional features:

Wide R wave in V1-2 (more than 50% of QRS width)
Higher R wave in V1-2 (more than 30% of S wave)
Transition zone ≤ V2
Notch in the ascending part of the R wave (V4-6)

ECG Idiopathic Left Ventricular Outflow Tract (LVOT) Tachycardia

Ventricular Tachycardia from the Left Ventricular Outflow Tract

Heart Rate: 140/min.
Wide QRS complexes (>0.12s)
Pattern of left bundle branch block

Wide QRS complexes
Deep S wave (V1)
Dominant R wave (V6)

Vertical axis (+100°)

Positive QRS in (II, III, aVF)

Transition zone (V3)

It is, however, VT from the left ventricular outflow tract due to the presence of additional features:

Wide R wave in V1 (more than 50% of QRS width)
Higher R wave in V1 (more than 30% of S wave)

Fascicular Ventricular Tachycardia

Posterior fascicular VT, Anterior fascicular VT, Upper septal fascicular VT

Fascicular VT is very rare

It constitutes 10% of idiopathic VTs

Mechanism is re-entry

Re-entry passes through one fascicle and the adjacent myocardium

Fast pathway is formed by the fascicle (anterior or posterior)
Slow pathway is formed by the adjacent myocardium near the fascicle

Occurs mainly in men aged 15-40 years
Referred to as verapamil-sensitive ventricular tachycardia

Responds well (terminates) after administration of verapamil

According to the location of re-entry, there are 3 types of fascicular VTs:

Posterior Fascicular VT

Re-entry is in the posterior fascicle
On ECG, there is left anterior hemiblock + right bundle branch block (RBBB)

Anterior Fascicular VT

Re-entry is in the anterior fascicle
On ECG, there is left posterior hemiblock + RBBB

Upper Septal Fascicular VT

Re-entry passes through both fascicles and the adjacent myocardium
On ECG, there are narrow QRS complexes and a pattern of left bundle branch block (LBBB) or RBBB
This is a ventricular tachycardia with narrow QRS complexes

Beware of interfascicular VT

Occurs in structurally damaged hearts (not idiopathic)

Most commonly associated with dilated cardiomyopathy

Re-entry passes through both the anterior and posterior fascicles

The fast pathway is in one fascicle
The slow pathway is in the other fascicle

ECG Anterior fascicular VT, RBBB morphology, Right axis deviation,

Anterior Fascicular Ventricular Tachycardia

Heart rate: 150/min.
QRS complexes are borderline wide (0.12s)
Right Bundle Branch Block (RBBB)

rSR' in V1 - The right rabbit ear is larger
Deep and wide S wave in V6

Left Posterior Hemiblock (axis deviation right +120º)

Negative QRS in I
Positive QRS in aVF, III

May be a supraventricular tachycardia with bifascicular block (RBBB + left posterior hemiblock)

However, the tachycardia continued after adenosine administration
Adenosine slows down the AV node and terminates supraventricular tachycardia

The tachycardia resolved after administration of verapamil

This is a verapamil-sensitive tachycardia, which is characteristic of Fascicular VT

This is Fascicular VT (re-entry is in the left anterior fascicle)

Even though typical signs of ventricular tachycardia are absent

ECG Posterior fascicular VT, RBBB morphology, left axis deviation, AV dissociation, fusion beat, capture beat

Posterior Fascicular Ventricular Tachycardia

Heart rate: 100/min.
QRS complexes are borderline wide (0.12s)
Right Bundle Branch Block (RBBB)

Dominant R wave in V1
Deep and wide S wave in V6

Left Anterior Hemiblock

Negative QRS in II, aVF
Positive QRS in I

The ECG shows classic signs of ventricular tachycardia

AV dissociation

In the continuous II lead, P waves (arrows) are seen that are independent of the QRS complexes

Fusion beat (6th QRS complex on the continuous II lead)
Captured beat (7th QRS complex on the continuous II lead - asterisk)

This is Fascicular VT (re-entry is in the left posterior fascicle)

Sources

ECG from Basics to Essentials Step by Step
litfl.com
ecgwaves.com
metealpaslan.com
medmastery.com
uptodate.com
ecgpedia.org
wikipedia.org
Strong Medicine
Understanding Pacemakers

Home /

Idiopathic Ventricular Tachycardia

Idiopathic ventricular tachycardia

Ventricular Tachycardia
Idiopathic Ventricular Tachycardia
Ventricular Tachycardias from Outflow Tracts
Ventricular Tachycardia from the Right Ventricular Outflow Tract
Ventricular Tachycardia from the Left Ventricular Outflow Tract
Fascicular Ventricular Tachycardia

Ventricular Tachycardia

Ventricular Tachycardia (VT) originates from a ventricular ectopic focus

Below the His bundle

The focus generates impulses with a frequency > 100/min.

The mechanism of impulses can be:

Re-entry (most common)
Increased automaticity
Trigger activity

VT results in wide QRS complexes (>0.12s)

Rarely, QRS complexes are narrow (<0.12s):
- VT from the ventricular septum area
- Fascicular ventricular tachycardia

VT consists of at least 3 consecutive ventricular beats

If fewer, it is ventricular extrasystoles

VT almost always occurs in a structurally damaged heart

Most commonly in a scar after an myocardial infarction

Idiopathic Ventricular Tachycardia

Idiopathic VT occurs in a structurally normal heart

(even without electrolyte disturbances or a prolonged QT interval)
10% of VT cases are idiopathic
90% of VT occurs in a structurally damaged heart

In idiopathic VT, an ectopic focus arises in the region of:

Ventricular outflow tracts
Fascicles of the left Tawar bundle

We recognize 3 types of idiopathic ventricular tachycardia

Ventricular Tachycardias from Outflow Tracts

VT in the context of arrhythmogenic right ventricular dysplasia in the outflow tract area

It is not idiopathic VT, because it involves a structurally altered right ventricle (including the outflow tract)

Ventricular tachycardias from the outflow tract are mostly idiopathic
There are 2 idiopathic VT from the outflow tract:

The mechanism is triggered activity
They respond well to adenosine, and are therefore often referred to as adenosine-sensitive VT

Ventricular tachycardia from arrhythmogenic right ventricular dysplasia does not respond to adenosine

Ventricular outflow tachycardias are

90% non-sustained monomorphic VT

Sometimes only numerous ventricular extrasystoles without VT are present
Extrasystoles occur at rest and disappear with physical exertion

10% sustained monomorphic VT

They occur during physical exertion

Ventricular Tachycardia from the Right Ventricular Outflow Tract

Right Ventricular Outflow Tract (RVOT) Tachycardia
Ventricular Tachycardia from the Right Ventricular Outflow Tract
It is the most common idiopathic VT

Accounts for 70% of all idiopathic VTs

Occurs in young individuals aged 20-50 years
Triggered by physical or emotional stress
The main vector points downwards towards the left ventricle
On ECG:

Shape of left bundle branch block
Positive QRS in inferior leads (II, III, aVF)
Transition zone > V2

Ventricular Tachycardia from the Right Ventricular Outflow Tract

Frequency: 160/min.
Wide QRS complexes (>0.12s)
Transition Zone (V3)
- The position of the transition zone differentiates VT from the right and left outflow tracts
Pattern of left bundle branch block
- Wide QRS complexes
- Deep S in V1
- Dominant R in V6
Vertical Axis (+ 90°)
- Positive QRS in II, III, aVF
AV Dissociation
- P waves visible in continuous lead II, deforming the QRS complexes
- AV dissociation is a fundamental sign of ventricular tachycardia

Ventricular Tachycardia from the Left Ventricular Outflow Tract

Left Ventricular Outflow Tract (LVOT) Tachycardia
Ventricular Tachycardia from the Left Ventricular Outflow Tract
Accounts for 20% of idiopathic VTs
Common sites of origin:

Aortic root near the origin of the coronary arteries (Valsalva sinus)
Basal part of the left ventricle
Epicardium of the left ventricular outflow tract

Main vector points downwards towards the left ventricle

Does not point towards the right ventricle because the left ventricle is more massive

On the ECG, it resembles the pattern of VT from the right ventricular outflow tract:

Pattern of left bundle branch block
Positive QRS in inferior leads (II, III, aVF)
VT from the left ventricular outflow tract has additional features:

Wide R wave in V1-2 (more than 50% of QRS width)
Higher R wave in V1-2 (more than 30% of S wave)
Transition zone ≤ V2
Notch in the ascending part of the R wave (V4-6)

Ventricular Tachycardia from the Left Ventricular Outflow Tract

Heart Rate: 140/min.
Wide QRS complexes (>0.12s)
Pattern of left bundle branch block

Wide QRS complexes
Deep S wave (V1)
Dominant R wave (V6)

Vertical axis (+100°)

Positive QRS in (II, III, aVF)

Transition zone (V3)

It is, however, VT from the left ventricular outflow tract due to the presence of additional features:

Wide R wave in V1 (more than 50% of QRS width)
Higher R wave in V1 (more than 30% of S wave)

Fascicular Ventricular Tachycardia

Fascicular VT is very rare

It constitutes 10% of idiopathic VTs

Mechanism is re-entry

Re-entry passes through one fascicle and the adjacent myocardium

Fast pathway is formed by the fascicle (anterior or posterior)
Slow pathway is formed by the adjacent myocardium near the fascicle

Occurs mainly in men aged 15-40 years
Referred to as verapamil-sensitive ventricular tachycardia

Responds well (terminates) after administration of verapamil

According to the location of re-entry, there are 3 types of fascicular VTs:

Posterior Fascicular VT

Re-entry is in the posterior fascicle
On ECG, there is left anterior hemiblock + right bundle branch block (RBBB)

Anterior Fascicular VT

Re-entry is in the anterior fascicle
On ECG, there is left posterior hemiblock + RBBB

Upper Septal Fascicular VT

Re-entry passes through both fascicles and the adjacent myocardium
On ECG, there are narrow QRS complexes and a pattern of left bundle branch block (LBBB) or RBBB
This is a ventricular tachycardia with narrow QRS complexes

Beware of interfascicular VT

Occurs in structurally damaged hearts (not idiopathic)

Most commonly associated with dilated cardiomyopathy

Re-entry passes through both the anterior and posterior fascicles

The fast pathway is in one fascicle
The slow pathway is in the other fascicle

Anterior Fascicular Ventricular Tachycardia

Heart rate: 150/min.
QRS complexes are borderline wide (0.12s)
Right Bundle Branch Block (RBBB)

rSR' in V1 - The right rabbit ear is larger
Deep and wide S wave in V6

Left Posterior Hemiblock (axis deviation right +120º)

Negative QRS in I
Positive QRS in aVF, III

May be a supraventricular tachycardia with bifascicular block (RBBB + left posterior hemiblock)

However, the tachycardia continued after adenosine administration
Adenosine slows down the AV node and terminates supraventricular tachycardia

The tachycardia resolved after administration of verapamil

This is a verapamil-sensitive tachycardia, which is characteristic of Fascicular VT

This is Fascicular VT (re-entry is in the left anterior fascicle)

Even though typical signs of ventricular tachycardia are absent

Posterior Fascicular Ventricular Tachycardia

Heart rate: 100/min.
QRS complexes are borderline wide (0.12s)
Right Bundle Branch Block (RBBB)

Dominant R wave in V1
Deep and wide S wave in V6

Left Anterior Hemiblock

Negative QRS in II, aVF
Positive QRS in I

The ECG shows classic signs of ventricular tachycardia

AV dissociation

In the continuous II lead, P waves (arrows) are seen that are independent of the QRS complexes

Fusion beat (6th QRS complex on the continuous II lead)
Captured beat (7th QRS complex on the continuous II lead - asterisk)

This is Fascicular VT (re-entry is in the left posterior fascicle)

Sources

ECG from Basics to Essentials Step by Step
litfl.com
ecgwaves.com
metealpaslan.com
medmastery.com
uptodate.com
ecgpedia.org
wikipedia.org
Strong Medicine
Understanding Pacemakers