Arrhythmias – Supraventricular Tachycardia (SVT) – Atrial Flutter Flashcards
Describe the pathophysiology of atrial flutter
Characterised by fast atrial and ventricular rate that can be fixed or variable
What are the 2 types of atrial flutter?
- Typical
- Atypical
Describe the pathophysiology of a typical atrial flutter
A re-entrant loop is located around the tricuspid valve
Describe the pathophysiology of an atypical flutter
A re-entrant loop occurs in various locations
What is the Cavotricuspid isthmus?
a band of tissue in the atria that more slowly conducts electrical signals and regulates the rate of atrial contraction
How can re-entrant loops form?
the refractory rate can be reduced, leading to the formation of re-entrant loops
What is a re-entrant loop?
These are abnormal ectopic sites which send signals at a very high rate that propagate back and forth from the ectopic site in a loop, causing the atria to contract repeatedly
Which node has a higher refractory period?
AV node
Do re-entrant loops lead to ventricular contractions every time the signal loops?
No
- although the re-entrant loop sends signals to the AV node at a high rate they do NOT lead to ventricular contraction every time the signal loops around
How often do ventricular contractions occur in typical atrial flutter?
every 2 or 3 atrial beats; a ratio of either 1:2 or 1:3
If the ratio of 1:2 and the atria was beating at 300bpm, what is the ventricular rate?
150bpm
What are causes of atrial flutter?
- Scarring
- Right Atrial Enlargement
What are symptoms of atrial flutter?
- Fatigue
- Palpitations
- Syncope
Describe the management for atrial flutter
Rate control medication or cardioversion:
- IV Amiodarone
- Beta blocker
As well as Catheter Radiofrequency Ablation
What does IV amiodarone do in atrial flutter?
restore normal rhythm
What do beta blockers do in atrial flutter?
to suppress further arrhythmias
What does catheter radiofrequency ablation do?
- destroys the re-entrant circuit/ectopic site
- 90 – 95% effective
What investigations are done for atrial flutter?
- ECG
- Echocardiogram
Others - XR, Thyroid FTs, FBC, ESR etc to check for possible causes
What is seen on ECG for atrial flutter?
usually presents with saw-tooth flutter waves on ECGs, seen in leads 2, 3 and aVF, with atrial rates between 240 – 340bpm
What might the ventricular rate be in atrial flutter?
The ventricular rate may be regular or irregular
Why is an echocardiogram done for atrial flutter?
Used to evaluate underlying cardiac function, structural abnormalities, evidence of coronary artery disease or pericardial fluid
What is used to investigate when cardioversion is being considered for atrial flutter?
A transoesophageal echo is used to detect for any thrombus formation
