Anaesthetic considerations in pregnant patients with cardiac arrhythmia

Question 1

Physiological changes in pregnancy that predispose to arrhythmia

Answer 1

• Oestrogen and progesterone enhance cardiac automaticity and adrenergic response in pregnancy
• Through increased L-type Ca channel in SA nodes
• Altered protein binding and increased renal clearance means the pharmacokinetic properties of some anti-arrhythmic drugs change
• Labour increased heart rate and autotransfusion of blood putting the heart under stress

Question 2

Normal ECG changes in pregnancy

Answer 2

• Sinus tachycardia
• Shortened PR and QT intervals
• Lt axis deviation (elevation of the diaphragm)
• T-wave inversion in V1 and V2

Question 3

Maternal and foetal risks in patients with arrhythmias

Answer 3

• Preterm labour
• APH, PPH
• Pre-eclampsia
• IUFD
• Cardiac arrest
• Heart failure

Question 4

Treatment of SVT in pregnancy

Answer 4

• Vagal manoeuvres
• Adenosine for acute episode
• Flecainide or procainamide for prevention (if pre-excitation)
• B-blockers or verapamil (if no pre-excitation)

Question 5

Treatment of AF/ flutter in pregnancy

Answer 5

• B-Blockers or digoxin for rate control
• Cardioversion if needed
• CAn consider flecainide, soltalol for prevention
• Anti-coagulate if in AF >48hrs

Question 6

Treatment of ventricular arrhythmias in pregnancy

Answer 6

• Immediate cardioversion
• B-blockers, flecainide or soltalol for monomorphic VT
• Amiodarone if the above has failed (can cause neonatal hypothyroidism and neurodevelopmental disorders)
• MgSO4 for polymorphic VT

Question 7

Treatment of bradyarrhythmias in pregnancy

Answer 7

• Atropine and glycopyrrolate
• Adrenaline, isoprenaline, glucagon, dopamine ok to use

Question 8

Synchronised DCCV in pregnancy

Answer 8

• Need to consider GA rather than sedation due to reflux risk in anyone over 20/40
• 70-150J 3x attempts with escalating energy
• Should have obstetric support and FHR monitoring before (if feasible) and after the procedure

Question 9

Anaesthetic considerations for long QT syndrome in pregnancy

Answer 9

• GA and neuraxial fine
• Avoid suxamethonium, ondansetron and ergometrine
• Avoid any LA with adrenaline mix
• Can consider prophylactic MgSO4 infusion to reduce the risk of polymorphic VT

Question 10

Anaesthetic considerations for Brugada syndrome in pregnancy

Answer 10

• Triggers include electrolyte disturbance, fever, pain, increased vagal tone
• Generally avoid bupivacaine because of its effect on cardiac Na channels- some studies suggest single dose spinal is ok
• Isoprenaline should be available to deal with acute tachycardia
• Short duration of propofol infusion as high risk of propofol infusion syndrome