Cardiovascular Flashcards
Normal ECG findings in pregnancy
Partly related to changes in the position of heart
- Slight left axis deviation due to altered heart position
Sinus tachycardia
Atrial and ventricular ectopics
Q-wave (small) and inverted T wave in lead III
ST segment depression and T wave inversion - inferior and lateral leads
QRS axis leftward shift
Normal cardiovascular examination findings in pregnancy
Bounding / collapsing pulse Ejection systolic murmur (in >90% of pregnant women) Loud first heart sound Third heart sound Relative sinus tachycardia Ectopic beats Peripheral oedema
CXR features in pregnancy
Heart is enlarged and pushed up by growing uterus
The aorta unfolds and the heart is rotated upwards and outwards
CXR may show heart displaced into a horizontal position, rotating to the left, with increased transverse diameter
Increased pulmonary vascular markings
Pulmonary venous distension
Elevated right hemidiaphragm
CV changes in pregnancy (physiology)
Drop in systemic vascular resistance - from peripheral vasodilation
Increase plasma volume
Increase stroke volume by 10-30%
HR increases from normal 70 to 80-90bpm
Cardiac output rises from 4L/min at week 10 to 6L/min at week 24 (~40% in pregnancy)
BP changes in pregnancy
Before the increase in CO can adequately compensate for the fall in SVR, BP begins to decrease in early pregnancy
Continues to decrease in second trimester until the nadir in SBP and DBP is reached by about 22-24 weeks’ gestation
From then on, there is a steady rise to pre-pregnancy levels until term
Post-partum - BP falls immediately after delivery, although tends to rise subsequently reaching a peak 3-6 days postpartum
- This may relate to return of normal vascular tone and a period of vasomotor instability while normal, and non-pregnant vasoregulation is re-established
Describe the New York Heart Association classification
Functional system based on symptoms
Class I
No breathlessness / uncompromised
No limitation on physical activity
Class II
Breathlessness on severe exertion / slightly compromised
Ordinary activity –> symptoms
Class III
Breathlessness on mild exertion / moderately compromised
Asymptomatic at rest
Less than ordinary activity –> symptoms
Class IV
Breathlessness at rest / severely compromised
Cardiac lesions that limit the ability to increase CO appropriately:
- Valvular stenosis - especially AS and MS
- Ventricular systolic impairment
- Cyanotic heart disease
- Ischaemic heart disease
- Dilated aortic root - increased risk of dissection
- Pulmonary artery HTN - a/w the highest risk of maternal mortality
Class IV of WHO classification
Conditions a/w extremely high risk of mortality or severe morbidity
Pregnancy is contraindicated
Severe MS
Symptomatic severe aortic stenosis
Bicuspid aortic valve with ascending aorta diameter >5cm
Marfan’s with aorta >45mm
Severe systemic ventricular systolic dysfunction with LVEF <30%
NYHA III-IV
Native severe coarctation
Fontan circulation with complications
Significant pulmonary arterial HTN
Previous peripartum cardiomyopathy with residual impairment
Antibiotic prophylaxis with heart disease
Current UK recommendations (NICE): antibiotic prophylaxis against infective endocarditis is not required for childbirth
Consider cover only for patients deemed to be at high risk of developing IE (e.g. previous IE) and for those who have the poorest outcome (e.g. cyanotic congenital heart disease)
Amoxicillin 2g IV + gentamicin 1.5mg/kg IV at onset of labour / ROM or prior to C/S
Maternal mortality of pulmonary HTN
Was 40% but more recent data suggest this may have fallen to 10-25%
Fixed pulmonary vascular resistance (PVR) means that these women cannot increase pulmonary blood flow to match the increased CO and they tolerate pregnancy poorly
High risk scenarios:
- Right to left shunt in Eisenmenger’s syndrome
- Right heart failure
- Escalating pulmonary HTN with pulmonary hypertensive crises
Diagnosis of pulmonary HTN
Non-pregnant elevation of mean (non-systolic) pulmonary artery pressure > 22mmHg at rest or 30mmHg on exercise in the absence of left to right shunt
If there is pulmonary HTN in the presence of a left to right shunt, the diagnosis of pulmonary vascular disease is particularly difficult and further investigation including cardiac catheterisation to calculate PVR is likely to be necessary
Causes of pulmonary HTN
Idiopathic pulmonary arterial hypertension (PAH)
Congenital heart disease-associated pulmonary hypertension - E.g. ASD / VSD with PAH - includes Eisenmenger’s syndrome
Chronic thromboembolic pulmonary HTN
Lung disease
- E.g. cystic fibrosis, interstitial lung disease, hypoxia
Connective tissue disease - E.g. scleroderma, SLE
Antenatal management of pulmonary HTN
MDT
Review meds re. safety in pregnancy
PAH-targeted therapies should be continued
- Sildenafil (aka VIAGRA) - safe to continue
Thromboprophylaxis
Elective admission for best rest, O2 therapy and escalation of targeted therapies
TOP should be considered
- TOP itself is associated with maternal mortality up to 7% (less than the risk of pregnancy continuing)
Intrapartum management of pulmonary HTN
MDT discussion and planning of delivery
No evidence that C/S vs. vaginal delivery, or regional anaesthesia vs. GA reduces mortality
In most case series delivery has been by C/S, often preterm
Telemetry
ICU
Avoid:
- Hypovolaemia (maintain preload)
- Acidosis
- Thromboembolism (heparin bridging)
- Pulmonary artery catheters (carry a risk of thrombus)
Systemic vasodilation (caution with regional anaesthesia, syntocinon - slow bolus)
Aggressive diuresis post-partum
Impacts of ecbolics - pulm HTN
Syntocinon - causes vasodilation, therefore give in slow bolus or infusion
Ergometrine - increases SVR (and pulmonary)
Carboprost - increases pulmonary vascular resistance –> pulmonary oedema
Misoprostol - safe
Post-delivery changes in CV physiology
Increased CO 60-80% due to relief of IVC obstruction and uterus emptying blood into the systemic circulation
~500-600ml blood from uterine circulation returns ~ autotransfusion (increases pre-load)
Then rapid decline to prelabour values within 1 hour of delivery
Transfer of fluid from extra-vascular space increased VR and SV
CO returns to pre-pregnancy levels 2 weeks after delivery
Impact of patent ductus arteriosus on pregnancy
Aorta to pulmonary artery
Left to right shunt, some oxygenated blood into pulmonary circuit
Most cases encountered would have been repaired in childhood (corrected cases) - Pose no problems in pregnancy
Uncorrected cases do well but are at risk of congestive cardiac failure
Impact of ASD on pregnancy
Commonest congenital heart defect in women
Usually well tolerated in pregnancy
If unrepaired:
- Potential risk of paradoxical embolism - low risk (Passage of thrombus from a vein to an artery)
- Atrial arrhythmia
If increase in left to right shunt following blood loss at delivery may deteriorate –> hypotension –> drop LVEF
Impact of VSD in pregnancy
Small (<1.25cm) or repaired defects - low risk during pregnancy
Increased volume load of left ventricle
Usually well tolerated in pregnancy unless Eisenmenger’s syndrome
Management of coarctation of the aorta
Usually corrected if diagnosed pre-pregnancy Risks if uncorrected: - Angina - HTN - Congestive heart failure - Aortic rupture - Aortic dissection
Ideally have MRI pre-pregnancy to exclude any aneurysm of post-stenotic dilatation around the repair site
Minimise risk of aortic dissection with strict BP control and beta-blockade to decrease cardiac contractility
What is Marfan’s syndrome?
Connective tissue disorder Autosomal dominant disorder 80% have cardiac involvement (usually mitral valve prolapse, mitral regurgitation, aortic root dilatation) Those with cardiac lesions tend to have offspring with cardiac abnormalities Other features of Marfan's - Increased height - Arm span > height - Arachnodactyly - Joint laxity - Depressed sternum - High arched palate - Dislocation of the lens
Risk of aortic dissection in pregnancy with Marfan’s?
1% if <4cm
Predictors for dissection and rupture:
- Pre-existing or progressive aortic root dilatation (10% if root >4cm)
- Positive FHx of dissection or aortic rupture
Management of Marfan’s in pregnancy
Genetics referral
BP check
Beta blockers shown to reduce the rate of aortic dilatation and the risk of complications in Marfan’s
- Serial growth scans if on beta blocker
Regular ECHO to assess aortic root diameter
Elective C/S - if aortic roots show progressive enlargement or >4.5cm
- Deliver in hospital with cardiothoracic support available
4 features of ToF
- VSD
- Pulmonary artery stenosis
- Overriding aorta
- RV hypertrophy