Cardiology: ToF; Flashcards
Which conditions make up ToF? [4]
Ventricular septal defect (VSD)
Overriding aorta
Pulmonary valve stenosis
Right ventricular hypertrophy
Describe the four conditions that make up ToF [4]
Overriding aorta
- refers to when the entrance to the aorta is placed further to the right than normal, above the ventricular septal defect. When the right ventricle contracts, squeezing blood upwards, the aorta is in the direction of travel of that blood, causing deoxygenated blood to enter the aorta, bypassing the lungs.
Pulmonary valve stenosis
- encourages blood to flow through the VSD and into the aorta rather than through the pulmonary valve into the pulmonary vessels.
The increased strain on the right ventricle as it pumps blood against the resistance of the left ventricle and pulmonary stenosis causes right ventricular hypertrophy, with thickening of the heart muscle.
The overriding aorta and pulmonary stenosis encourage blood to be shunted from the right heart to the left, bypassing the lung. This right-to-left cardiac shunt means deoxygenated blood bypasses the child’s lungs and enters the systemic circulation, causing cyanosis. The severity of pulmonary stenosis determines the degree of cyanosis.
What are risk factors that could predispose a patient to ToF? [4]
Risk factors and associations include:
* Increased maternal age (over 40 years)
* Alcohol consumption in pregnancy
* Maternal diabetes
* Genetic conditions (e.g., DiGeorge syndrome and Down’s syndrome)
* Congenital rubella syndrome
How is ToF mainly detected? [1]
Most cases are identified during the antenatal scans.
Describe the presentation of ToF [+]
Shortness of breath
- tachypnoea and exertional dyspnoea due to limited pulmonary blood flow resulting from right ventricular outflow tract obstruction and ventricular septal defect.
Cyanosis
- Tet spells (intermittent episodes of cyanosis, coupled with irritablilty and increased resp effort)
Finger clubbing
- Clubbing of the fingers and toes may be present due to chronic hypoxia.
Poor feeding
Polycythaemia
- is often seen in these patients as a compensatory response to chronic hypoxia.
Poor weight gain
Tetralogy of Fallot produces an ejection systolic murmur heard loudest in the pulmonary area (second intercostal space, left sternal border).
How might ToF present on an ECG? [2]
Electrocardiogram (ECG): It may show right axis deviation and right ventricular hypertrophy but these findings are non-specific.
Describe the Mx of ToF [3]
In neonates:
- a prostaglandin infusion may be used to maintain the ductus arteriosus.
- This allows blood to flow from the aorta to the pulmonary arteries. A stent may be inserted to keep the ductus arteriosus open.
A Blalock-Taussig shunt
- involves creating a connection between a systemic artery (e.g., the left subclavian artery) and a pulmonary artery, increasing blood flow to the lungs.
- This may be used as a temporary measure in neonates who are too small for total repair.
Total surgical repair by open heart surgery is the definitive treatment
- Primary complete repair: Primary complete repair; closure of the ventricular septal defect (VSD) and relief of right ventricular outflow tract obstruction (RVOTO)
What can be used to mx Tet spels in ToF? [1]
Beta-blockers: These agents may be used to control symptoms associated with hypercyanotic (‘blue’) spells by reducing infundibular spasm.
Long term cardiac follow up for ToF patients is needed in order to monitor for which conditions? [4]
How do you monitor these conditions? [1]
Lifelong cardiology follow-up is necessary due to potential late complications such as
- pulmonary regurgitation
- right ventricular dysfunction
- arrhythmias
- residual shunts or stenosis.
**Regular echocardiography **is required to monitor right ventricular function and pulmonary valve status. Cardiac magnetic resonance imaging (MRI) may be beneficial in certain cases for detailed evaluation.
antibiotic prophylaxis is given for TOF patients for certain treatments they might have. Why? [1] And which conditions? [3]
Endocarditis prophylaxis: Patients with TOF are at increased risk of infective endocarditis, thus antibiotic prophylaxis is recommended for certain dental procedures, respiratory tract incisions, or procedures involving infected skin or musculoskeletal tissue.
How might an older child present with a Tet spell? [1]
How might you tell younger children to sit? [1]
Why? [1]
Older children may squat when a tet spell occurs. Younger children can be placed in the “knees to chest” position.
Squatting increases systemic vascular resistance, encouraging blood to enter the pulmonary vessels.
Describe exactly is going on in a Tet spel
Tet spells are intermittent cyanotic episodes caused by a temporary worsening of the right-to-left shunt.
They occur when the pulmonary vascular resistance increases or the systemic resistance decreases.
- For example, extra carbon dioxide is generated during physical exertion, which is a vasodilator that reduces systemic vascular resistance
- Reduced systemic vascular resistance encourages blood to flow from the right ventricle to the aorta rather than to the pulmonary vessels and lungs.
What is the medical managment of Tet spells? [4]
- Oxygen
- IV morphine (decreases respiratory drive and pulmonary vascular resistance)
- IV fluids (increases circulating volume)
- IV beta blockers (e.g., propranolol)
- Phenylephrine infusion (increases systemic vascular resistance)
Lecture
The critical feature of the degree of ToF relates to… [1]
The degree of pulmonary stenosis
Describe what is meant by Transposition of the great arteries (TGA)
a congenital cardiac malformation characterised by an abnormal arrangement of the primary blood vessels, namely the pulmonary artery and aorta.
- The right ventricle pumps blood into the aorta and the left ventricle pumps blood into the pulmonary vessels.
- In TGA, these vessels arise from inappropriate ventricles resulting in two separate circulatory systems - systemic and pulmonary: Blood from the systemic venous system drains into the right side of the heart and is pumped straight back into the aorta. Blood from the pulmonary veins drains into the left side of the heart and is pumped straight back into the pulmonary arteries. These two separate circulations do not mix.
- The pathophysiology involves parallel rather than serial circulation which leads to cyanosis.
How do you manage immediate survival of ToA? [1]
What are the other management options? [2]
Immediate survival depends on a shunt connecting the systemic and pulmonary circulation. This can occur across a patent ductus arteriosus, atrial septal defect, or ventricular septal defect.
- A prostaglandin E2 infusion is used to maintain the ductus arteriosus. This allows blood to flow from the aorta to the pulmonary arteries and lungs for oxygenation.
Balloon septostomy
- involves inserting a catheter into the foramen ovale via the umbilicus and inflating a balloon to create a ** connection between the atria**. This allows blood from the pulmonary veins to flow from the left atrium to the right atrium, where it can flow to the right ventricle and aorta.
Definitive management involves an arterial switch operation.
- The aorta and pulmonary trunk are switched to their correct locations. This is usually performed within a few days of birth.
What are the types of cardiomyopathy that could occur in children due to acquired [4] and genetic [5] causes
Developed cardiomyopathies:
- which causes are more likely to be earlier postnatal [1] or later postnatal [1]
Severe CoA: earlier on: major abnormality needed to cause v high demands on heart
VSD: later on - e.g. 1month, because strain on heart arises from overload (which takes time to develop)
What are red flag symptoms for cardiac syncope in kids?
Syncope: Red flags
* Lack of prodrome
* Palpitations
* Chest pain
* Induced by exercise
* Past cardiac history
* Family history of early cardiac death, arrhythmia or sudden death
Vasovagal syncope tends to be preceded by painful / emotional stimuli x visual changes x dizziness
You want to understand about risks of cardiac abnormalities. What questions could you ask to determine this?
Further history:
* Tachypnoea/cyanosis at birth
* Maternal illnesses, drug abuse
* Sibling with congenital heart disease
* Sudden death in family
You suspect a patient has congenital aortic stenosis.
How would this patient present?
Aortic stenosis causes an ejection systolic murmur heard loudest in the aortic area, in the second intercostal space, right sternal border. It has a crescendo-decrescendo character and radiates to the carotids.
Other signs that may be present on examination are:
* Ejection click just before the murmur
* Palpable thrill during systole
* Slow-rising pulse and narrow pulse pressure
Symptoms include:
* Fatigue
* Shortness of breath
* Dizziness
* Fainting
Congenital aortic stenosis tends to worsen over time.
Treatment options include: [3]
Percutaneous balloon aortic valvuloplasty (inflating a balloon to stretch the valve via a catheter)
Surgical aortic valvotomy (open surgery via a midline sternotomy incision to widen the aortic valve)
**Valve replacement **(open surgery via a midline sternotomy incision to replace the aortic valve)
Describe what is meant by Ebstein’s anomaly?
Ebstein’s anomaly is a congenital heart condition where the tricuspid valve is set lower in the right side of the heart (towards the apex), causing a bigger right atrium and a smaller right ventricle.
- The tricuspid valve does not function normally, resulting in tricuspid regurgitation (blood flowing back from the right ventricle to the right atrium). There is reduced right ventricular function.
Ebstein’s anomaly is often associated with an [3xcardiac conditions].
Ebstein’s anomaly is often associated with an atrial septal defect with a right-to-left shunt. Blood flow from the right atrium to the left atrium allows blood to bypass the lungs, leading to cyanosis.
It is also often associated with Wolff-Parkinson-White syndrome and supraventricular tachycardia.
Ebstein’s anomaly may be caused by exposure to [drug] in-utero.
Ebstein’s anomaly may be caused by exposure to lithium in-utero.
How would Ebstein’s anomaly present on a jugular venous wave? [1]
prominent ‘a’ wave in the distended jugular venous pulse
- In Ebstein’s anomaly, there is an abnormal downward displacement of the tricuspid valve into the right ventricle. This causes a portion of the right ventricle to effectively become part of the right atrium (atrialisation), leading to a larger than normal ‘A’ wave in JVP due to increased atrial contraction. Tricuspid regurgitation can occur as a result of this displacement, leading to prominent V waves.
Ebstein’s anomaly may be asymptomatic until adolescence or adulthood.
It may present with:
[4]
Ebstein’s anomaly may be asymptomatic until adolescence or adulthood.
It may present with:
Arrhythmias (e.g., supraventricular tachycardia)
Heart failure (e.g., shortness of breath and oedema)
Collapse or cardiac arrest
Cyanosis (when there is an associated atrial septal defect)
What is the medical [1] and surgical [1] managment of Ebsteins anomaly?
Medical management involves treating arrhythmias and heart failure.
Surgical management may involve tricuspid valve repair or replacement.
You suspect a patient has congenital pulmonary stenosis.
What are the significant signs [5] and symptoms [6] you might see if this patient had this?
Pulmonary stenosis is often asymptomatic.
More significant pulmonary valve stenosis can present with:
* Fatigue on exertion
* Shortness of breath
* Dizziness
* Syncope (fainting)
Signs on examination may include:
* Ejection systolic murmur heard loudest at the pulmonary area (second intercostal space, left sternal border)
* Palpable thrill in the pulmonary area
* Right ventricular heave (due to right ventricular hypertrophy)
* Raised JVP with giant a waves
* Widely split second heart sound
Describe how a widely split second heart sound occurs in pulmonary stenosis
The narrow pulmonary valve prolongs the time it takes for the right ventricle to empty.
By contrast, the left ventricle empties relatively quickly through a healthy aortic valve.
Closure of the pulmonary valve is delayed and occurs noticeably later than the closure of the aortic valve.
This causes a widely split second heart sound, meaning that two separate sounds are heard, rather than the usual single second heart sound.
Tx for pulmonary stenosis? [3]
Treatment options include:
* Percutaneous balloon aortic valvuloplasty(inflating a balloon to stretch the valve via a catheter)
* Surgical aortic valvotomy
* Valve replacement
What would the signs and examination findings be of Eisenmenger syndrome?
Signs of pulmonary hypertension:
* Right ventricular heave (the right ventricle contracts forcefully against increased pressure in the lungs)
* Loud P2 (forceful shutting of the pulmonary valve)
* Raised JVP
* Peripheral oedema
Murmurs related to the underlying septal defect:
Atrial septal defect:
- Mid-systolic, crescendo-decrescendo murmur loudest at the upper left sternal border
Ventricular septal defect:
- Pan-systolic murmur loudest at the left lower sternal border
Patent ductus arteriosus:
- Continuous crescendo-decrescendo “machinery” murmur
Findings related to the right-to-left shunt and chronic hypoxia:
* Cyanosis
* Finger clubbing
* Dyspnoea (shortness of breath)
* Plethoric complexion (reddish skin related to polycythaemia)
[1] is the only definitive treatment once Eisenmenger syndrome develops.
A heart-lung transplant is the only definitive treatment once Eisenmenger syndrome develops.
Ejection systolic
