Tachyarrhythmia's Flashcards
Define the term “Tachyarrhythmia’s”
Refers to an abnormally fast heart rate (>100bpm)
Define paroxysmal tachyarrhythmia
It is when a tachyarrhythmia occurs intermittently
Tachyarrhythmias are broadly divided into two groups.
Name these two groups?
Supraventricular tachyarrhythmias
and
Ventricular tachyarrhythmias
Supraventricular tachyarrhythmias refers to a problem ____ the ventricles
a) Above
b) Within
a) Above
Supraventricular tachyarrhythmias refers to a problem Above the ventricles
Ventricular tachyarrhythmias refers to a problem ____ the ventricles
a) Above
b) Within
b) Within
Ventricular tachyarrhythmias refers to a problem Within the ventricles
What is the key ECG feature of Supraventricular tachyarrhythmias
Characterised by narrow QRS complexes
What is the key ECG feature of ventricular tachyarrhythmias
Characterised by broad QRS complexes
Name 4 examples of Supraventricular tachycardia’s (SVT)
Sinus tachycardia
Atrial tachycardia
Atrial flutter
Atrial fibrillation (AF)
Atrioventricular nodal reentrant tachycardia (AVNRT)
Atrioventricular reentrant tachycardia (AVRT)
Name 3 examples of Ventricular tachycardia’s (VT)
Ventricular tachycardia (VT)
Polymorphic ventricular tachycardia (Torsades de pointes)
Ventricular fibrillation (VF)
Sinus tachycardia is an example of what type of tachyarrhythmias:
a) Supraventricular tachycardia (SVT)
b) Ventricular tachycardia (VT)
a) Supraventricular tachycardia (SVT)
Atrial tachycardia is an example of what type of tachyarrhythmias:
a) Supraventricular tachycardia (SVT)
b) Ventricular tachycardia (VT)
a) Supraventricular tachycardia (SVT)
Atrial flutter is an example of what type of tachyarrhythmias:
a) Supraventricular tachycardia (SVT)
b) Ventricular tachycardia (VT)
a) Supraventricular tachycardia (SVT)
Atrial fibrillation is an example of what type of tachyarrhythmias:
a) Supraventricular tachycardia (SVT)
b) Ventricular tachycardia (VT)
a) Supraventricular tachycardia (SVT)
Ventricular tachycardia (VT) is an example of what type of tachyarrhythmias:
a) Supraventricular tachycardia (SVT)
b) Ventricular tachycardia (VT)
b) Ventricular tachycardia (VT)
Torsades de pointes is an example of what type of tachyarrhythmias:
a) Supraventricular tachycardia (SVT)
b) Ventricular tachycardia (VT)
b) Ventricular tachycardia (VT)
Ventricular fibrillation (VF) is an example of what type of tachyarrhythmias:
a) Supraventricular tachycardia (SVT)
b) Ventricular tachycardia (VT)
b) Ventricular tachycardia (VT)
What is the ECG features of sinus tachycardia
Sinus rhythm with a heart rate > 100 bpm
What are the ECG features of atrial tachycardia
Occurs due to an abnormal focus of activity undergoing rapid depolarisation in the atria
ECG features:
- Tachycardia (>100 bpm)
- Narrow QRS complexes
- Abnormal P waves
Describe what is going on in the heart to cause atrial flutter
It is caused by an aberrant macro-circuit within the right atrium i.e. the depolarised wave returns to the SA node reactivating the depolarisation of the atria
What is the ECG features of atrial flutter
Sawtooth baseline (fluttering P waves), which is best visualised in the inferior leads (II, III, aVF)
Sawtooth baseline is characteristic ECG pattern of which arrhythmia
Atrial flutter - a type of supraventricular tachycardia
What leads are the sawtooth baseline ECG pattern best seen on
The inferior leads (II, III and aVF)
Why is 2:1 block classically seen in atrial flutter
This is due to the fast atrial rate some of the atrial activity is not conducted to the ventricles
Higher degrees of block can occur
What is this ECG pattern
Sinus tachycardia
What is this ECG pattern
Atrial tachycardia
What is this ECG pattern
Atrial flutter - Sawtooth baseline (fluttering P waves),
What is this ECG pattern
Ventricular tachycardia (VT)
Describe what is going on in the heart to cause ventricular tachycardia
Occurs due to rapid, recurrent ventricular depolarisation from a focus within the ventricles
What is the most common cause of ventricular tachycardia
Commonly due to scarring of the ventricles following MI
What are the ECG features of ventricular tachycardia
Rapid, broad-complex tachycardia (QRS >120 ms)
Ventricular tachycardia (VT) without a pulse is what kind of cardiac arrest rhythm
‘Shockable’ cardiac arrest rhythms
What is this ECG pattern
Torsades de pointes
Describe what is going on in the heart to cause Torsades de pointes
Type of VT that is due to depolarisation of multiple foci within the ventricles leading to variable QRS complexes
What are the ECG features of Torsades de pointes
Similar to normal ventricular tachycardia however it looks like QRS complex is twisting around the baseline
What is the management of atrial flutter
Control rate with beta blocker
What is the management of Ventricular tachycardia (VT)
Shockable
Adrenaline should be given after the third shock, and then during alternate cycles.
Amiodarone should be given after the third shock, and another dose considered after five shocks
What is the management of Torsades de pointes
Usually are self-limiting and terminate spontaneously however they can progression into ventricular tachycardia
What is this ECG pattern
Ventricular fibrillation (VF)
Describe what is going on in the heart to cause ventricular fibrillation (VF)
Incompatible with life
Occurs when the ventricular muscle fibres contract independently
What are the ECG features of Ventricular fibrillation (VF)
No coordinated electrical activity with a chaotic, fibrillating baseline.
What is the management for Ventricular fibrillation (VF)
‘Shockable’ cardiac arrest rhythms that requires immediate DC cardioversion
Name the 4 possible rhythms in a pulseless unresponsive patient
Ventricular tachycardia
Ventricular fibrillation
Pulseless electrical activity (all electrical activity except VF/VT, including sinus rhythm without a pulse)
Asystole (no significant electrical activity)
Name the two shockable cardiac arrest rhythms
Ventricular tachycardia
Ventricular fibrillation
Name the two non-shockable cardiac arrest rhythms
Pulseless electrical activity (all electrical activity except VF/VT, including sinus rhythm without a pulse)
Asystole (no significant electrical activity)
In stable patients with Supraventricular Tachycardia (SVT) what is the first line managment option
Vagal manoeuvres e.g. Valsalva manoeuvre
Valsalva manoeuvre is a breathing method in which the patient breathes out strongly through their mouth whilst holding their nose. This creates a forceful strain that can trigger their heart to go back into sinus rhythm
In stable patients with Supraventricular Tachycardia (SVT) what is the second line managment option (if vagal manoeuves are not successful or are contra-indicated)
IV adenosine 6mg
What is an appropriate alternative to IV adenosine 6mg as a second line therapy for managing supraventricular tachycardia
Verapamil, a calcium channel blocker
What is the mechanism of action of adenosine as a pharmaeutical tool for managing supraventricular tachycardia’s
It works by temporarily blocking conduction through the AV node “resetting” it back to sinus rhythm
When you are giving IV bolus adenosine to managing supraventricular tachycardia what do you need to warn the patient of?
Patients should be warned that they may have trouble breathing, chest tightness and feeling of dying / impending doom when adenosine is injected
IV adenosine is given rapidly (over 1-3 seconds) followed by what?
20mL IV normal saline bolus
Adenosine can be given maximum 3 times.
Describe the dosing of these adenosine bolus doses?
1st dose is IV adenosine 6mg
If no improvement IV Adenosine 12mg can be administered, followed by a further 12mg
What is happening in the heart to cause Wolff-Parkinson White Syndrome
Pre-excitation syndrome i.e. the ventricles contract early
Characterised by a congenital accessory pathway i.e. an extra electrical pathway connecting the atria and ventricles
Normally there is only one pathway connecting the atria and ventricles called the atrio-ventricular node
The extra pathway that is present in Wolff-Parkinson White Syndrome is often called the Bundle of Kent
Adenosine should be avoided in which patient groups?
Those that have any of the following co-morbidities:
Asthma / COPD / heart failure / heart block / severe hypotension
What is the definitive management of Wolff=Parkinson White Syndrome
Radiofrequency ablation of the accessory pathway
What are the hallmark ECG features of Wolff-Parkinson White Syndrome
- Short PR interval (< 0.12 seconds) – as there is no AV conduction delay
- Wide QRS complex (> 0.12 seconds)
- “Delta wave” which is a slurred upstroke on the QRS complex
What is the main concern in patients with Wolff-Parkinson White Syndrome?
The main concern in WPW is if the patient develops AF
The chaotic atrial electrical activity characterised by AF can pass through the accessory pathway leading to a rapid ventricular response. This could deteriorate into ventricular fibrillation.
Other than atrial fibrillation, what can cause an irregularly irregular pulse?
Ventricular ectopics
ventricular ectopics disappear when the heart rate gets over a certain threshold (therefore exercise can be a useful way of differentiating AF from VEs without an ECG).
