Cardiovascular Flashcards
What are the most common acyanotic congenital heart diseases?
- Ventricular septal defects
- Atrial septal defects
- Patent ductus arteriosus
- Coarctation of the aorta
- Aortic valve stenosis
What is the most common congenital heart disease type?
Ventricular septal defects (accounts for ~30%)
What are the most common cyanotic congenital heart diseases?
- Tetralogy of Fallot
- Transposition of the great arteries
- Tricuspid atresia
What is the difference between cyanotic and acyanotic heart diseases?
- Cyanotic = heart defects that reduce the amount of oxygen delivered to the rest of the body
- Acyanotic = heart defects where blood contains sufficient oxygen but is pumped throughout the body abnormally
What is a VSD?
Hole in the septum separating the ventricles of the heart
What is the murmur associated with VSDs?
Loud, harsh pansystolic murmur, loudest at the left lower sternal edge
What is the pathophysiology of VSDs?
Blood is shunted from the left to the right ventricle, this:
- Increases pressure on the right hand side of the heart
- Increases load delivered to the left side (more blood is pumped to the lungs and returned to the left side)
What is Eisenmenger’s syndrome?
- Due to prolonged pulmonary hypertension from left to right shunt
- Right ventricular hypertrophy and increased right ventricular pressure eventually exceeding the left ventricle and reversing the shunt
- Results in cyanosis and clubbing
- Indication for heart and lung transplant
How are VSDs classified?
Congenital and acquired (post MI impacting the septum)
What are congenital VSDs associated with?
Chromosomal disorders:
- Down’s syndrome
- Edward’s syndrome
- Patau syndrome
- Cri-du-chat syndrome
Congenital infections
Acquired causes
- Post-MI affecting the septum
When can VSDs be detected in utero?
During the routine 20 week scan
What are the post-natal presentations of VSDs?
Failure to thrive
Features of heart failure:
- Hepatomegaly
- Tachypnoea
- Tachycardia
- Pallor
Murmur
What are the complications of VSDs?
- Aortic regurg (poorly supported right coronary cusp resulting in cusp prolapse)
- Infective endocarditis
- Eisenmenger’s syndrome
- Right heart failure
- Pulmonary hypertension
What would ECG demonstrate in VSD?
- Left ventricular hypertrophy
- P pulmonale
- Biventricular hypertrophy
Which investigation is used to definitively diagnose VSDs?
Transthoracic echocardiogram
What is the management of VSDs?
Small VSDs that are asymptomatic usually close spontaneously and require simple monitoring
Moderate - large VSDs usually result in some degree of heart failure in the first few months:
- Nutritional support
- Medication for heart failure eg. diuretics
- Surgical closure of defect
Which is the most likely congenital heart defect to be found in adulthood?
Atrial septal defects
50% of patients are dead at 50 years
What are the three types of ASD?
- Ostium secundum (defect in septum secundum)
- Ostium primum (defect in septum primum)
- Patent ductus arteriosus
Ostium secundum more common
What can play a role in ASD development?
- Maternal alcohol consumption
- Rubella infection during pregnancy
- Maternal diabetes
What are the general features of ASDs?
- Ejection systolic murmur, fixed splitting of S2
- Embolism may pass from venous system to the left side of the heart causing a stroke
What are the features of ostium secundum ASD?
- Associated with Holt-Oram syndrome (tri-phalangeal thumbs)
- ECG: RBBB with RAD
What are the features of ostium primum?
- Present earlier than ostium secundum defects
- Associated with abnormal AV valves
- ECG: RBBB with LAD, prolonged PR interval
How are ASDs usually detected?
Often an incidental finding of ejection systolic murmur, loudest lower-left sternal edge due to flow of blood through pulmonary valve
- Patients can present as decompensated in heart failure
What is the management of ASDs?
Management depends on severity:
- Most managed conservatively
- Surgical closure may be necessary for larger defects (or those causing significant symptoms/ complications)
- Routine ECGs used for monitoring ASDs
What is patent ductus arteriosus?
Connection between the pulmonary trunk and descending aorta, generally classed as acyanotic lasting beyond the first four weeks after birth
When does the ductus arteriosus usually close?
With the first breaths due to increased pulmonary flow which enhances prostaglandins clearance
Which factors contribute to persistance of patent ductus arteriosus?
- Prematurity
- Genetic predispositions
- Babies born at high altitude
- Maternal rubella in the first trimester
What are the clinical features of patent ductus arteriosus?
- Left subclavicular thrill
- Continuous ‘machinery’ murmur
- Large volume, bounding, collapsing pulse
- Wide pulse pressure
- Heaving apex beat
What is the definitive investigation for patent ductus arteriosus diagnosis?
Echocardiography
When is management of patent ductus arteriosus required?
If the infant presents with symptoms
What is the medical treatment of patent ductus arteriosus?
NSAIDs (indomethacin or ibuprofen)
- Inhibits prostaglandin synthesis
- Closes the connection in the majority of cases
(surgical ligation indicated in about 8% of cases)
When would prostaglandin E1 be given in patent ductus arteriosus?
If it’s associated with another congenital heart defect amenable to surgery, prostaglandin E1 is useful to keep the duct open until after surgical repair
When does tetralogy of fallot usually present?
1-2 months
What are the four characteristic findings of tetralogy of fallot (TOF)?
- Overriding aorta (aortic opening directly in line with the VSD rather than the left ventricle)
- VSD
- Right ventricular outflow tract obstruction (caused by congenital valvular pathology, overriding aorta and RV hypertrophy contribute)
- Right ventricular hypertrophy (due to increased outflow resistance from the pulmonary stenosis)
What determines the degree of cyanosis and clinical severity in TOF?
The severity of the right ventricular outflow tract obstruction
What factors have been implicated in increasing the risk of TOF?
- Genetic factors
- Maternal use of alcohol
- Maternal use of drugs
- Diabetes mellitus
- Maternal age >40
What are the clinical features of TOF?
- Episodic hypercyanotic ‘tet’ spells, due to near occlusion of the RV outflow tract leading to right to left shunt
- Left to right shunt
- Ejection systolic murmur (pulmonary stenosis, VSD usually doesn’t cause a murmur)
- Right sided aortic arch (25% of patients)
- Chest x-ray shows a ‘boot-shaped’ heart, ECG shows right ventricular hypertrophy
What are the features of tet spells?
- Tachypnoea
- Severe cyanosis that can result in loss of consciousness
- Typically occur when the infant is upset, in pain or has a fever
What are the investigations for TOF?
1st line
- Echocardiography: confirms diganosis
Other
- Cardiac catheterization: may be needed to delineate coronary artery anatomy and assess degree of pulmonary vascular disease
What are the aims of treatment in TOF?
- Correction of the right ventricular outflow tract obstruction
- Closure of the ventricular septal defect
What is the management in an emergency situation like a tet spell?
- Positioning the infant on their back and flexing the knees
- Oxygen administration
- Prophylactic use of propranolol is practised in some centres to reduce infundibular spasm
What are the anatomical changes in transposition of the great arteries (TGA)?
- Pulmonary trunk leaves the left ventricle
- Aorta leaves the right ventricle
A closed circuit is created meaning oxygenated blood leaving the lungs is never delivered to respiring tissues and deoxygenated blood from tissues is circulated around the body
What is the aetiology of TGA?
- Normal heart development includes spiraling of the aortopulmonary septum
- TGA spiraling fails to occur resulting in two parallel and separate circulations
Shunts remaining open after birth (foramen ovale, ductus arteriosus) increase the chance of survival