ACEM Fellowship

Table of Contents

Cardiac disease

More deaths from cardiac disease than pre-eclampsia and haemorrhage combined
Mostly congenital cardiac disease
Shift towards ischaemic heart disease now
Mortality of 1% in uncomplicated conditions to >40% in Eisenmenger’s syndrome
Physiological changes
Susceptibility to aortocaval compression
Reduced SVR
Increased blood volume and CO by 40-50% at 20 weeks and further increase by up to 50% in labour
Inability to meet the above challenges can lead to cardiac failure
If right to left shunt, drop in SVR encourages blood to bypass lungs, leading to severe hypoxaemia

Flow gradients across stenosed valves increase in pregnancy due to increased CO so valve area is a more accurate assessment method
Pulse oximetry can help monitor right-to-left shunt
Thromboprophylaxis is paramount as cardiac patients are at increased risk
Previously C/S was performed routinely under GA, however, trend towards vaginal birth unless Caesarean indicated for obstetric reasons
Low-dose epidural regimes have been shown to be safe
Peripartum complications such as bleeding, pulmonary oedema, arrhythmia, sudden increase in pulmonary vascular resistance or fall in systemic vascular resistance are tolerated poorly
Syntocinon can cause life-threatening drop in SVR with hypotension, tachycardia and worsening of right-toleft shunt
Witholding altogether risks PPH so usually half-dose over longer time
Phenylephrine can be used to raise SVR in order to limit right-to-left shunt if hypoxaemia problematic • Consider endocarditis prophylaxis requirements

Dilated cardiomyopathy

Floppy LV with reduced systolic and diastolic function
Drop in SVR in pregnancy reduces afterload (beneficial) but may also drop preload (esp. if acute) with drop in CO

Increase in HR risks increase in LVOT obstruction and syncope
Drop in SVR may improve forward flow but if diastolic pressure too low, risks impaired coronary perfusion

Dilated cardiomyopathy seen between last month of pregnancy and 6 months post-partum
Increased risk of thromboembolism
No prior heart disease
Treat as for CCF

Changes of pregnancy include increased HR, stroke volume and cardiac output requirements
Stenotic worse than regurgitant

4 predictors of adverse maternal outcome
Left heart obstruction (mitral valve area <2cm^2, aortic valve area <1.5 or peak LVOT gradient >30mmHg) – 1 point
Prior cardiac event (heart failure, TIA, stroke, arrhythmia) – 1 point
NYHA 3 or 4 – 1 point
Left ventricular systolic function <40 percent – 1 point
0 points = 5% risk of adverse cardiac event
1 point = 27%
>1 point = 62%
Significant pulmonary HTN is also a high risk factor not factored into this specifically

Increased HR (in pregnancy or delivery) further impairs diastolic LV filling leading to acute heart failure
Increased cardiac output leads to increase LA pressures, AF and pulmonary oedema
Beta-blockers are the mainstay of therapy to control heart rate and prolong diastolic LV filling time
Treat heart failure with diuretics

• Reduced SVR may assist forward flow but overall increased CO requirements usually lead to pulmonary oedema if LV dysfunction exists

Mostly congenital bicuspid in women of childbearing age
Inability to tolerate increased CO given fixed outflow tract obstruction leads to increased LVEDP, pulmonary oedema and arrhythmias
Restrict activities, treat pulmonary oedema with diuretics but remember pre-load dependent
Drop in SVR (afterload) beneficial for forward flow but risk of drop in diastolic coronary flow to hypertrophied LV
May need noradrenaline to maintain diastolic coronary flow and preload in crisis

Mostly congenital bicuspid aortic valve
Diuretics and vasodilators helpful to improve forward flow and prevent fluid overload
Tachycardia reduces time/volume of regurgitant flow and is actually beneficial

Reduced FRC, splinting of diaphragm and increased O2 demand
Asthma carries higher risk of morbidity and mortality during pregnancy
CF have additional stress of higher nutritional requirements
Remember PaCO2 45 in pregnancy is greatly deranged compared to a non-pregnant female (as normally respiratory alkalosis)

Metoclopramide Class A
NSAID’s
- Safe up to 32 weeks as no data to suggest malformations
- Later use can lead to premature closure of ductus arteriosus, oligohydramnios due to renal impairment and delayed labour
- Compatible in breastfeeding
Gentamicin is not safe in pregnancy (Class D)
Oxycodone is safe in breatfeeding if given occasionally

Last Updated on September 27, 2021 by Andrew Crofton