TORSADES DE POINTES [QT INTERVAL PROLONGATION]

Question 1

What is Torsades de pointes?

Answer 1

This is where the heart beats in a very unusual way, typically very fast, causing not enough oxygen to be pumped around the body and the brain is starved of oxygen,
leading to blackouts, fainting, and even death.

Question 2

Causes of Torsades De Pointes?

Answer 2

• Stress
• Strenuous exercise
• Sudden noise
• Drugs
• Hypokalaemia

Question 3

What is the drug treatment for Torsades De Pointes?

Answer 3

IV Magnesium Sulphide

Question 4

What drugs cause QT Interval Prolongation?

Answer 4

ABCs of QT Interval prolongation

• AntiArrhythmics (amiodarone, sotalol, flecainide)
• AntiBiotics (quinolones, macrolides, aminoglycosides)
• AntipsyChotics (haloperidol, quetiapine, risperidone)
• AntiDepressants (SSRIs, tricyclic antidepressants) and Diuretics
• AntiEmetics (ondansetron)
• AntiFungals (azoles)

Question 4

What is Amiodarone used for?

Answer 4

To treat arrhythmias

Question 5

What is the adult dose for Amiodarone?

Answer 5

200mg THREE times a day for 1 week,
then 200mg TWICE a day for 1 week,
then 200mg daily (Maintenance dose)

Question 6

What are the side effects of Amiodarone?

Answer 6

Acronym PHOTOgenicBITCH:

• Photosensitivity and Peripheral Neuropathy
• Bradycardia
• Interstitial lung disease
• Thyroid Issues (Hyper/Hypo)
• Corneal Microdeposits
• Hepatoxicity

Question 7

What are the patient carer advice for Amiodarone?

Answer 7

• Shield skin from sunlight during and for several months after treatment
• Use a wide spectrum sunscreen - at least SPF 30
• Seek medical attention if:
  • Shortness of breath
  • Light headaches, tiredness, fainting
  • Palpitations
  • Chest pain

Question 8

What are the monitoring requirements for Amiodarone?

Answer 8

• Thyroid function test
• Liver function test
• Serum potassium concentration
• Chest X-Ray
• Annual Eye Test
• Blood pressure
• ECG (with IV use)

Question 9

What does Digoxin do?

Answer 9

It helps control atrial fibrillation, atrial flutter and heart failure for patients in sinus rhythm

Question 10

How is the maintenance dose determined?

Answer 10

The maintenance dose is determined by the ventricular rate at rest, which should not fall below 60bpm persistently.

Respond may take several hours, and is therefore not suitable for rapid heart rate control

Question 11

What route cannot be taken for Digoxin?

Answer 11

Intramuscular route is NOT recommended

Question 12

How many times a day is Digoxin usually taken for?

Answer 12

Usually once daily because Digoxin has a long half-life.

Very high doses may be divided to twice daily to prevent nausea

Question 13

What’s the maintenance dose in Atrial Fibrillation?

Answer 13

125 to 250mcg daily

Question 14

What’s the maintenance dose in Worsening / severe heart failure?

Answer 14

62.5 to 125mcg daily

Question 15

What’s the Therapeutic and Toxic range?

Answer 15

Therapeutic range: 1 to 2 mcg/L

Toxic range: 1.5 to 3 mcg/L

Question 16

What should be done if toxicity occurs?

Answer 16

Withdraw digoxin and reverse with digoxin-specific antibody fragments