Supraventricular (Narrow Complex) Tachycardias****

Question 1

What are supraventricular (narrow complex) tachycardias?

Sinus tachycardia - where does it originate from?

Atrial tachycardia - where does it originate from?

Nodal/junctional tachycardia - where does it originate from?

SUPRAVENTRICULAR MEANS IT AFFECTS THE ATRIA!!!!

Answer 1

Tachycardia
Due to faulty impulse formation or conduction for tissue above the ventricles

From the SA node

From the atrial tissue but can be focal (e.g. ectopic AT, multifocal AT or non-focal (AF or macro re-entrant atrial tachycardia)

AV node due to re-entrant pathway

Question 2

What are some of the symptoms of tachycardia? - 4

Why do these symptoms happen?

What type of supraventricular tachycardia would have a sudden onset and what would cause a gradual onset?

Answer 2

Palpitations
Dizzy
SOB
Chest pain

When your heart is beating too fast, it may not pump enough blood to the rest of your body.

Re-entrant tachycardia - Atrioventricular nodal reentry tachycardia (AVNRT) is the most common type of supraventricular tachycardia. Episodes often start and end suddenly, and occur because of a reentrant circuit — also called an accessory pathway — located in or near the AV node that causes the heart to beat prematurely.

Sinus tachycardia

Question 3

ECG findings:

QRS is narrowed obviously. How would you know it is narrowed?

P-waves:

• Sinus tachycardia
• Atrial tachycardia
• Nodal/junctional tachycardia
• AF

Just read the above and research!

Answer 3

It is less the 3 small squares or less than 0.12 seconds

=====
Inverted (ectopic atrial tachycardia)

Varying morphology (multifocal atrial tachycardia)

Sawtooth (atrial flutter)

Absent (AF)

Question 4

ECHO findings:

What is it usually?

What side could you see HF in?

Answer 4

Normal

Left side

Tachycardia-induced cardiomyopathy develops slowly and appears reversible by left ventricular ejection fraction improvement, but recurrent tachycardia causes rapid decline in left ventricular function and development of heart failure.

Question 5

AV nodal re-entrant tachycardia (AVNRT):

Pathophysiology

What causes episodes?

What are people like between episodes?

Answer 5

Individuals have slow and fast pathway in the AV node and are at risk

Premature atrial ectopic beats

Normal and have a normal ECG

Question 6

AVNRT:

What does it stand for?

ECG:

• QRS?
• What happens to the PR interval?

P wave:

• Where can the P wave sometimes be hidden under?
• Where may the P wave appear after?
• What may happen to the P wave if it is visible?

Typical AVNRT:

• What happens to the P wave?
• What is the coordination of contraction like?

Atypical AVNRT:

• Does the atria contract before or after the ventricles?
• Where is the inverted P wave found?

Answer 6

Simultaneous contraction of atriums and ventricles

AV nodal re-entrant tachycardia

Narrow

Reduced PR interval

P wave within the QRS (often hidden)
P wave after the QRS 
P wave if visible is inverted especially in inferior leads
=========
It is usually hidden

Atrial contraction after ventricular

Between QRS and the T wave

Question 7

AVRT and Wolff-Parkinson White syndrome:

What does AVRT stand for?

What is WPW syndrome?

What type of wave do you see on the ECG for WPW?

It is usually assymptomatic and usually picked up on an ECG!

Why is WPW relevant in paediatrics?

Why can it lead to death?

Answer 7

AV re-entrant tachycardia

A condition in which there is an extra electrical pathway in the heart - Get pre-excitation of ventricles

Delta waves before normal depolarisation

WPW syndrome is one of the most common causes of fast heart rate problems in infants and children.

If they have episode of AF are at risk of developing VF and suffer cardiac death

Question 8

Atrial tachycardia:

Ectopic AT:

• What is it?
• What happens to his P wave?

Multifocal AT:
- What is it?

Atrial flutter:

• What is it?
• What wave do you see on ECG?
• What is a key feature?

Answer 8

Rhythm arising from an ectopic focus within the atrium

Inverted P wave 
=======
Rhythm arising from multiple ectopic foci in the atrium with irregular conduction to ventricles 
=======
Macro re-entrant atrial tachycardia 

Sawtooth F waves instead of P waves

High HR - 150 bpm

Question 9

Management of SVT:

Acute treatment:
- What node needs to be targeted?

Vagal manoeuvres can be tried first. What is the manoeuvre called?

What can also be done, which is used in vasovagal syncope?

Answer 9

Slow the AV node

Modified Valsalva manoeuvre
(The Valsalva manoeuvre is a noninvasive way to convert patients from SVT to sinus rhythm. It increases the myocardial refractory period by increasing intrathoracic pressure, thus stimulating baroreceptors in the aortic arch and carotid bodies, increasing vagal tone.)

Carotid sinus massage

Question 10

Management of SVT:

1st line - What drug can be given, which is used for cardioversion to stop the heart? - A

2nd line - What calcium channel blockers can be used?

3rd line - What drugs can be used which care used in cardioversion? - A, F

Cardioversion is used for those who are haemodynamically unstable or in atrial flutter.

Answer 10

Adenosine -1st

Verapamil - 2nd

Amiodarone / flecainide - 3rd

Question 11

Prevention of SVT:

What can be taught to patients which is a manoeuvre?

A range of drugs can be prescribed by a cardiologist.

What can be used to cure it completely?

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Answer 11

Teach Valsalva

Cather ablation under LA

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