The cardiovascular disease - congenital heart disease and hypertension Flashcards
Describe the foetal circulation
Oxygenated blood is carried from the placenta to the right side of the heart via the following route: placenta –> umbilical vein –> ductus venous –> inferior vena cava –> right atrium
From the right atrium, the oxygenated blood can take three different routes:
1. Via the foramen oval: This makes up the majority of blood flow. Blood travels from right atrium –> foramen oval –> left atrium –> left ventricle –> aorta
- Via the ductus arteriosus: this makes up the majority of blood flow. Blood travels from right atrium –> right ventricle –> pulmonary artery –> ductus arteriosus –> aorta. Blood flows through the ductus arteriosus instead of the lungs because the systemic vascular resistance (SVR) has a lower resistance than the pulmonary vascular resistance (PVR)
- Via the foetal lungs: only a tiny amount of blood is left to circulate through the immature lungs
Describe the changes in circulation at birth
After birth, the placenta no longer supplies blood to the baby. As the baby takes its first breath, the pulmonary vascular resistance (PVR) drops significantly lower than the SVR, then progressively over 4-6 weeks. Blood now experiences minimal resistance from the pulmonary vasculature, and this starts flowing through the lungs
The ductus arteriosus will close and form the remnant ligament arteriosum
The oval foramen flap closes with increased atrial pressure (the entry of blood into the left atrium through the pulmonary veins will also push the floppy septum premium up against the septum secundum, thereby closing the foremen over). This then forms the fossa ovalis
In utero, left and right chamber pressure are equal. After birth, right-sided pressure gradually falls over several weeks due to the the fall in PVR
What are the five general clinical features of congenital heart disease
mnemonic ‘CHAMP
- Cyanosis
- Heart failure
- Arrhythmia
- Murmur
- Pulmonary hypertension
Women with complex CHD who are planning on getting pregnant are, despite treatment are at higher risk of complications during pregnancy.
Describe how these patients should be managed
- They should undergo specialist assessment to plan their care
- Early conversations
- Young women: contraception, pregnancy risks, risks of assisted reproductive therapy
- Foetal risks: loss, pre-term
- Risks for child: loss of parent in child hood - In severe individuals with severe CHDs, it may be advisable to avoid pregnancy altogether e.g., contraception
- Foetal echocardiography should be performed in the 26th week of pregnancy to exclude foetal abnormality
Give 4 overall simple predictions of maternal risk
- Prior cardiac event (TIA, stroke, arrhythmia, heart failure)
- NYHA > grade II pre-pregnancy
- Left heart obstruction - mitral or aortic stenosis, CoA
- LVEF < 40%
Give 3 risk scores used in pregnancy
- WHO
- RPAC
- CARPREG 2
Describe the psychosocial issues involved in congenital heart disease
- Ill health and poor schooling - employment difficulties
- Difficulty with insurance
- Self-image: scar on chest
- Housing, prescription charges, driving
- Lifelong follow up, tests, spectre of intervenetion
- Reduced QoL
What is atrial septal defect (ASD)?
ASD refers to communication between the left and right atria
Describe the epidemiology of ASDs
ASDs are mostly sporadic, with certain risk factors (e.g., maternal alcohol a abuse)
A small percentage is familial
Describe the pathophysiology of atrial septal defect
Most commonly arises because of the failure of the foramen ovale to close, secondary to a defect in the osmium secundum
As blood comes into the left atrium there will be a low resistance in the left ventricle –> a proportion goes back into the right atrium via shunt (but depends on size of shunt and pressure gradient) –> leads to right atrial dilatation, right ventricle dilation and pulmonary artery dilation –> increased pulmonary blood flow
AKA pre-tricuspid shunt (occurs before tricuspid valve)
Clinical features of atrial septal defect
a) Symptoms
b) Signs
a)
- Usually asymptomatic
- Palpitations in AF
- Signs of heart failure: fatigue, breathlessness, peripheral oedema, hepatomegaly
b)
- Prominent RV impulse
- Murmur: a soft ejection systolic murmur best heard at the upper left sternal edge –> due to increase blood flow past the pulmonary valved
- Fixed (in all stages of respiration) widely split soft S2
- Late features: arrhythmia (AF), heart failure (due to right heart dilatation)
Describe the presentation and symptoms of small ASD in
a) Neonate
b) Young child
c) Adult
a) Nothing
b) Incidental murmur
c) Paradoxical embolus, stroke
Describe the presentation and symptoms of medium ASD in
a) Neonate
b) Young child
c) Adult
a) Nothing
b) Recurrent pneumonia, poor growth, incidental murmur
c) Exercise intolerance, recurrent pneumonia, atrial arrhythmia
Describe the presentation and symptoms of large ASD in
a) Neonate
b) Young child
c) Adult
a) Nothing
b) Exercise intolerance, fatigue, poor growth
c) Atrial arrhythmia, tricuspid regurgitation, heart failure, pulmonary hypertension
Describe the 1st line and 2nd line investigations of ASD
1st line
- Echocardiography
2nd line
- ECG
Describe the ECG changes in ASD
Not diagnostic, but can show tall P waves (P-pulmonale) representing right atrial enlargement of partial RBBB
Describe the CXR signs in an older child or adult
- Cardiomegaly
- Dilation of the right atrium
- Dilation of the right ventricle
- Prominent main pulmonary artery
- Increased pulmonary vascular markings
Describe the management of ASD
Management depends on the extent of the shunt
- Observation: no surgical intervention is necessary if there is a small ASD as the majority close spontaneously by 2 years. Intervention is indicated if the condition worsens
- Transcatheter closure: most defects can be closed by percutaneous transcatheter closure but very large ASDs or premium ASDs require surgical closure
Give 3 indications for closure in ASDs
- Large ASD
- Primum ASD
- Heart failure
- Symptomatic
- RA and RV enlargement
- Net L to R shunt Qp:Qs > 1.5
- No cyanosis at rest or exercise
- Systolic PA pressure <50% systemic pressure
- PVR < 1/3 SVR
What is a ventricular septal defect?
A ventricular septal defect (VSD) refers to communication between the left and right ventricle
Describe the pathophysiology of a ventricular septal defect
When the left ventricle contracts, blood goes through aortic valve –> the shunt causes a lower pressure in right ventricle than aorta –> blood flow goes from left to right ventricle via shunt and into pulmonary artery –> the extra blood flow goes into the lungs, back into the left atrium and then left ventricle –> some will go back again through the pulmonary artery –> high pulmonary flow leads to pulmonary artery dilation –> resistance in lungs (pulmonary vascular resistance) stays low so increasing loading of left atria and ventricle chamber –> left heart (atrial and ventricular) dilatation
Describe the presentation and symptoms of small VSD in
a) Young child
b) Adult
a) Incidental murmur
b) Incidental murmur endocarditis
Describe the presentation and symptoms of medium VSD in
a) Neonate
b) Young child
c) Adult
a) > 4 weeks incidental murmur, sweatiness with feeds
b) Poor growth, murmur, frequent chest infections
c) Incidental murmur, endocarditis
Describe the presentation and symptoms of large VSD in
a) Neonate
b) Young child
c) Adult
a) > 4 weeks tachypnoea, poor feeding, failure to thrive
b) Frequent chest infections, exercise intolerance, fatigue, poor growth
c) Breathlessness, fatigue, HF, Pulmonary hypertension
What are the key features of VSD’s?
A small VSD will cause no symptoms
Key features
- Shortness of breath
- Sweating and poor feeding in children
What are the examination findings of a VSD?
Murmur: a pansystolic murmur best heard at the left sternal border. A small VSD produces a louder murmur than large VSDs - this loud murmur is given the name ‘Maladie de Roger’. A thrill is palpable sometimes
Displaced, hyper dynamic apex
Hepatosplenomegaly