Supraventricular Tachycardia Flashcards
What characterises a narrow complex tachycardia.
Rate >100BPM and QRS
What sort of tachycardia does SVT cause.
Narrow complex.
What is the treatment for SVT. (4)
If adenosine fails, give verapamil (not if no a beta blocker).
If no response, give a further 5mg IV over 3mins (
How should you treat narrow complex tachycardias.
As AF as it is the most likely cause.
What characterises a SVT.
Narrow complex QRS.
Re entry circuit or automatic focus involving the atria.
What is AVNTR.
Atrioventricular nodal re-entrant tachycardia is due to re-entry in a circuit involving the AV node and its two right atrial input pathways: a fast and a slow pathway.
What does AVNRT produce.
A regular tachycardia of 120BPM.
How long can AVNRT last.
From a few seconds to many hours.
What may be a features of AVNRT.
Polyuria due to the release of ANP.
What is normally seen on an ECG in a patient with AVNRT. (3)
Tachycardia.
Normal QRS complex.
There may be rate-dependent bundle branch blocks.
What are the symptoms of AVNRT. (4)
Awareness of a rapid, foreceful regular heart beat.
Chest discomfort.
Lightheadedness.
Breathlessness.
How do you treat AVNRT. (5)
Treatment is not always necessary.
Episode can be terminated by carotid sinus pressure or by the Valsalva manoeuvre.
Adenosine or verapamil will restore sinus rhythm.
IV beta blockers or flecainide can also be used.
In rare cases, DC cardioversion is needed.
What is the treatment in patients with recurrent SVT. (2)
Catheter ablation (>90% success). Prophylaxis with oral beta blockers, verapamil or flecainide.
What are the main forms of SVT. (8)
Sinus tachycardia. AVNRT. AVRT. AF. Atrial flutter. Atrial tachycardia. Multifocal atrial tachycardia. Accelerated junctional tachycardia.
What are the ECG features of AVNRT. (2)
No visible P waves.
Or inverted P waves immediately before or after QRS complex.
What are the ECG changes in AVRT.
P waves visible between QRS and T waves.
What is WPW.
A type of AVRT.
What is seen in multifocal atrial tachycardia on an ECG. (2)
Multiple P wave morphologies.
Irregularly irregular RR intervals.
What is seen in atrial tachycardia on an ECG.
Organized atrial activity with P wave morphology different from sinus rhythm preceding QRS.
What is inappropriate sinus tachycardia.
It is a persistent increase in resting HR unrelated to or out of proportion with the level of physical or emotional stress.
What are the symptoms of SVTs. (9)
Tachycardia. Anxiety. Dizziness. Dyspnoea. Neck pulsation. Central chest pain. Weakness. Polyuria. Syncope (10-15%).
What are the side effects of adenosine. (5)
Bronchospasm. Flushing. Chest pain. Heaviness of the limbs. Sense of impeding doom.
What are some causes of atrial tachycarrhythmias. (5)
Hypertension. Valvular heart disease. Coronary artery disease. Thyrotoxicosis. Electrolyte disturbance (hypokalaemia).
