Arrhythmias – Supraventricular Tachycardia (SVT) – Atrial Flutter

Question 1

Describe the pathophysiology of atrial flutter

Answer 1

Characterised by fast atrial and ventricular rate that can be fixed or variable

Question 2

What are the 2 types of atrial flutter?

Answer 2

• Typical
• Atypical

Question 3

Describe the pathophysiology of a typical atrial flutter

Answer 3

A re-entrant loop is located around the tricuspid valve

Question 4

Describe the pathophysiology of an atypical flutter

Answer 4

A re-entrant loop occurs in various locations

Question 5

What is the Cavotricuspid isthmus?

Answer 5

a band of tissue in the atria that more slowly conducts electrical signals and regulates the rate of atrial contraction

Question 6

How can re-entrant loops form?

Answer 6

the refractory rate can be reduced, leading to the formation of re-entrant loops

Question 7

What is a re-entrant loop?

Answer 7

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

Question 8

Which node has a higher refractory period?

Answer 8

AV node

Question 9

Do re-entrant loops lead to ventricular contractions every time the signal loops?

Answer 9

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

Question 10

How often do ventricular contractions occur in typical atrial flutter?

Answer 10

every 2 or 3 atrial beats; a ratio of either 1:2 or 1:3

Question 11

If the ratio of 1:2 and the atria was beating at 300bpm, what is the ventricular rate?

Answer 11

150bpm

Question 12

What are causes of atrial flutter?

Answer 12

• Scarring
• Right Atrial Enlargement

Question 13

What are symptoms of atrial flutter?

Answer 13

• Fatigue
• Palpitations
• Syncope

Question 14

Describe the management for atrial flutter

Answer 14

Rate control medication or cardioversion:

• IV Amiodarone
• Beta blocker

As well as Catheter Radiofrequency Ablation

Question 15

What does IV amiodarone do in atrial flutter?

Answer 15

restore normal rhythm

Question 16

What do beta blockers do in atrial flutter?

Answer 16

to suppress further arrhythmias

Question 17

What does catheter radiofrequency ablation do?

Answer 17

• destroys the re-entrant circuit/ectopic site
• 90 – 95% effective

Question 18

What investigations are done for atrial flutter?

Answer 18

• ECG
• Echocardiogram
  Others
• XR, Thyroid FTs, FBC, ESR etc to check for possible causes

Question 19

What is seen on ECG for atrial flutter?

Answer 19

usually presents with saw-tooth flutter waves on ECGs, seen in leads 2, 3 and aVF, with atrial rates between 240 – 340bpm

Question 20

What might the ventricular rate be in atrial flutter?

Answer 20

The ventricular rate may be regular or irregular

Question 21

Why is an echocardiogram done for atrial flutter?

Answer 21

Used to evaluate underlying cardiac function, structural abnormalities, evidence of coronary artery disease or pericardial fluid

Question 22

What is used to investigate when cardioversion is being considered for atrial flutter?

Answer 22

A transoesophageal echo is used to detect for any thrombus formation