Structural Heart Defects Flashcards
What % of all births have some from of cardiac defect
1%
Are cardiac defects more common in males or females
males
What structural heart defects are more common in females
Atrial Septal defect
Persistence ductus arteriosus
Aetiology of Congenital Heart Disease
- One child with defect increases the chance of the second child having another defect
- Maternal prenatal rubella infection - persistent ductus arteriosus and pulmonary valvular and arterial stenosis
- Maternal alcohol misuse - septal defects
- Single genes associated e.g. Trisomy 21
- Drugs
- Diabetes of mother
- Genetic abnormalities e.g. the familial form of arterial spatial defect and congenital heart block
What congenital heart defects associate with Trisomy 21 (Down’s syndrome)
Septal, Mitral and Tricuspid valve defects
What drugs can lead to congenital heart defects
Thalidomide
Amphetamines
Lithium
What diseases can result from maternal prenatal rubella infection
Persistent ductus arteriosus and pulmonary valvular and arterial stenosis
Clinical presentation of congenital heart disease
(Should be recognised early was earlier treatment means better response to treatment)
Central cyanosis Pulmonary hypertension Clubbing of fingers (prolonged cyanosis) Growth retardation (common in children with cyanotic heart disease) Syncope
Adults or adolescents with congenital heart disease present with specific common problems related to the longstanding structural nature of these conditions:
• Endocarditis - especially in small ventricular septal defects or bicuspid aortic valve
• Calcification and stenosis of congenitally deformed valves e.g. bicuspid aortic valve
• Atrial and ventricular arrhythmias
• Sudden cardiac death
• Right heart failure
• End-stage heart failure
Classification of congenital heart disease: Acyanotic defects with shunts
Atrial septal defect
Ventricular septal defect
Patent ductus arteriosus
Partial anomalous venous drainage
Classification of congenital heart disease: Acyanotic defects without shunts
Coarctation of aorta
Congenital aortic stenosis
Classification of congenital heart disease: Cyanotic defects with shunts
Fallots tetraology
Transposition of the great vessels
Severe Ebstein’s anomaly
Classification of congenital heart disease: Cyanotic defects without shunts
Severe pulmonary stenosis
Tricuspid atresia (abnormal narrowing of passage in body)
Pulmonary atresia
Hypoplastic left heart
What is most common form of congenital heart disease
Bicuspid Aortic Valve (BAV)
occurring in 1-2% of live births
What is BAV
Bicuspid Aortic Valve
Aortic valves only has 2 cusps
Issues of BAV
Work well at birth and go undetected, but can become severely stenotic infancy
Degenerate quicker than normal valves
Become regurgitant earlier than normal valves
Associated with coarctation and dilation of the ascending aorta
May develop into aortic stenosis and thus predisposes valve to Infective Endocarditis
Intense exercise may accelerate complications
Epidemiology of Atrial septal defects
Represents one third of congenital heart disease
More common in women
What can happen if atrial septal defects are left untreated
Develop right heart overload and dilatation - the right ventricle is complaint and easily dilates to accommodate the increased pulmonary flow, however this can result in:
- Right ventricular hypertrophy
- Pulmonary hypertension
- Eisenmenger’s reaction
- Increased risk of infective endocarditis
Atrial septal defects: a probe can be passed through which embryogenic foramen
Foramen ovale (between atria)
A probe can be passed through the layers of the foramen ovale (called the Primum and Secundum) so is sometimes known as “Probe patent foramen ovale”
Atrial septal defects: Clinical Presentation
Dysponea
Exercise intolerance
May develop atrial arrhythmias from right atrial dilatation
Pulmonary flow murmur
Fixed split second heart sound (delayed closure of the pulmonary valve because more blood has to get out)
Atrial septal defects: Diagnosis
CXR:
• Large pulmonary arteries
• Large heart
ECG:
• Right bundle branch block (RBBB) due to right ventricle dilatation
Echocardiogram:
• Hypertrophy and dilation of right side of heart and pulmonary arteries
Atrial septal defects: Treatment
Surgical closure
Percutaneous key hole surgery
Atrial septal defect - which direction is the shunt?
Left-to-right
Ventricular septal defect - which direction is the shunt?
Left-to-right
What % of congenital heart defects are ventricular septal defects
20%
Ventricular septal defect - what is the result on blood flow through the lungs?
Increased blood flow through lungs
Clinical presentation of Ventricular septal large defects
The large volumes of blood flowing through the pulmonary vasculature lead to pulmonary hypertension and eventual Eisenmenger’s complex, when right ventricular pressure becomes higher than the left, as a result blood starts to shunt right-to-left resulting in cyanosis
Small breathless skinny baby Increased respiratory rate Tachycardia CXR - Big heart Murmur varies in intensity
Clinical presentation of Ventricular septal small defects
- Large systolic murmur
- Thrill (buzzing sensation)
- Well grown
- Normal heart rate
- Normal heart size
Treatment of ventricular septal defects
- Medical initially since many will spontaneously close
- Surgical closure
- If small then no intervention is required
- Prophylactic antibiotics
- If moderately sized lesion; Furosemide, ACE inhibitor e.g. ramipril and digoxin
What are AVSDs
Atrio-Ventricular Septal Defects
hole in centre of heart
Types of AVSDs
Complete
Partial
Example of a genetic disease associated with AVSDs
Down’s syndrome
AVSDs: Describe key differences in heart anatomy
Instead of two separate atrio-ventricular valves there is JUST ONE big malformed one which usually leaks
Clinical presentation of Complete AVSD
- Breathlessness as neonate
- Poor weight gain and feeding
- Torrential pulmonary flow which can result in Eisenmenger’s resulting in cyanosis over time
Clinical presentation of Partial AVSD
- Can present in late adulthood
* Presents similar to ventricular/atrial septal defect e.g. dysponea, tachycardia, exercise intolerance etc.
AVSD Treatment
- Pulmonary artery banding if large defect in infancy - band reduces blood flow to lungs thereby reducing pulmonary hypertension and Eisenmenger’s syndrome
- Partial defect may be left alone if no right heart dilation
What is the Ductus Arteriosus
Ductus arteriosus is a persistent communication between the proximal left pulmonary artery and the descending aorta
Describe blood flow in foetal life through the heart
Pulmonary vascular resistance is high (since bronchioles are filled with fluid and vessels are vasoconstricted due to lack of O2) and the right heart pressure exceeds that of left - consequently flow is from right to left atrium through foramen ovale, and from pulmonary artery to aorta via ductus arteriosus
What normally happens to ductus arteriosus at birth
ductus arteriosus closes within a few hours of birth in response to decreased pulmonary resistance
In what cases can the ductus arteriosus persist
in premature babies and in cases with maternal rubella, the ductus persists
Pathophysiology of patent ductus arteriosus (stay open at birth) and consequences
If it remains open then there is an abnormal left-to- right shunt (from aorta to pulmonary artery) and eventually means that the lung circulation is overloaded with pulmonary hypertension (leading to Eisenmenger syndrome) and right side cardiac failure (due to right ventricular hypertrophy in response to increased afterload) subsequently.
Also increases risk of infective endocarditis
Clinical presentation of Patent Ductus Arteriosus
- Continuous ‘machinery’ murmus
- Bounding pulse
- If large then large heart and breathlessness
- Eisenmenger’s syndrome with differential cyanosis that is clubbed and blue toes BUT pink and not clubber fingers
- Tachycardia
Diagnosis of Patent Ductus Arteriosus
CXR:
• With large shunt the aorta and pulmonary arterial system may be prominent
ECG:
• May demonstrate left atrial abnormality and left ventricular hypertrophy
Echocardiogram:
• May show dilated left atrium and left ventricle
Treatment of Patent Ductus Arteriosus
- Can be closed surgically or percutaneously
- Low risk of complications
- Venous approach may require an AV loop
- Indometacin (prostaglandin inhibitor) can be given to stimulate duct closure
Give example of a Prostaglandin inhibitor and example of a use
Indometacin
Can be given to stimulate duct closure
Describe Coarctation of Aorta
How does it result in stronger perfusion of upper body than the lower?
A narrowing of the aorta at, or just distal to, the insertion of the ductus arteriosus (distal to the origin of the left subclavian artery).
Net result is a narrowing of the aorta just after the arch, with excessive blood flow being diverted through the carotid and subclavian vessels into systemic vascular shunts to supply the rest of the body, thus stronger perfusion to upper body compared to lower.
What conditions associate with Coarctation of Aorta?
Turner syndrome
Berry aneurysms
Patent Ductus Arteriosus
How does coarctation of aorta lead to decreased renal perfusion?
Narrowing of aorta around ductus arteriosus insertion (just after the arch) results in excessive blood flow through the carotid and subclavian vessels, thus stronger perfusion through upper body compared to lower body.
What can result from decreased renal perfusion?
Systemic hypertension as kidneys think they need to activate RAAS.
(This systemic hypertension can persist even after surgical correction)
Clinical presentation of coarctation of aorta
- Often asymptomatic for many years
- Right arm hypertension
- Bruits (buzzes) over the scapulae and back from collateral vessels
- Murmur
- Headaches and nose bleeds (due to hypertension)
- Hypertension in the upper limbs
- Discrepant blood pressure in the upper and lower body (will notice radial pulse BEFORE femoral pulse)
Longer term problems of coarctation of aorta
Hypertension:
- Early coronary artery disease
- Early strokes
- Sub-arachnoid haemorrhage
Diagnosis of coarctation of aorta
CXR:
• Dilated aorta indented at the site of the coarctation
ECG:
• Left ventricular hypertrophy
CT:
• Can accurately demonstrate the coarctation and quantify flow
Treatment of coarctation of aorta
- Surgery
- Balloon dilatation (preferred for re-coarctation) and stenting
- Risk of aneurysm formation at the site of repair
What is most common form of cyanotic congenital heart disease?
Tetralogy of Fallot
What does tetralogy of fallot consist of?
- A large, maligned Ventricular Septal Defect (VSD)
- An overriding aorta
- Right ventricular outflow obstruction
e. g. due to pulmonary stenosis - Right ventricular hypertrophy
What can result from stenosis of right ventricle outflow due to tetralogy of fallot?
Leads to the right ventricle being at a higher pressure than the left
Thus ‘blue/deoxygenated’ blood passes from the right ventricle to the left ventricle
The patients are BLUE i.e CYANOTIC
Clinical presentation/Diagnosis of tetralogy of fallot
- Central cyanosis
- Low birthweight and growth
- Dysponea on exertion
- Delayed puberty
- Systolic ejection murmurs
- CXR: Boot shaped heart
Treatment of tetralogy of fallot
- Full surgical treatment during first two years of life due to the progressive cardiac debility and cerebral thrombosis risk
- Often get pulmonary valve regurgitation in adulthood and require redo surgery
Types of pulmonary stenosis
Valvar
Sub-valvar
Supra-valvar
(narrowing of outflow of right ventricle)
Describe features of severe pulmonary stenosis
- Right ventricular failure as neonate
- Collapse
- Poor pulmonary blood flow
- Right ventricular hypertrophy
- Tricuspid regurgitation
Describe features of mild pulmonary stenosis
- Well tolerated for many years
- Right ventricular hypertrophy
Treatment of pulmonary stenosis
- Balloon valvoplasty - place catheter with balloon through femoral vein then inflate balloon at stenosis to crush it but this can result in regurgitation
- Open valvotomy
- Shunt - to bypass the blockage
Describe complete transposition of the great arteries (TGA) and when survival is possible
Involves the aorta coming off the right ventricle and the pulmonary trunk coming off the left ventricle.
Two closed circulations result.
Survival is only possible if there is communication between the two circuits and virtually all have some form of atrial septal defect with blood mixing.
Epidemiology of complete transposition of the great arteries (TGA)
More common in men and associated with diabetes
Treatment of complete transposition of the great arteries (TGA)
Atrial switch operation
What is dextrocardia?
Heart points to right side of chest instead of left. Associated with severe cardiovascular abnormalities
