Paediatric Cardiology - Cyanotic Heart Defects Flashcards
What are the four major defects in tetralogy of fallot?
Pulmonary stenosis
Overriding aorta
Right ventricular hypertrophy
Ventricular septal defect
Why do you get arterial desaturation in tetralogy of fallot?
Blood is shunted across the VSD into the aorta
What determines the severity of cyanosis in Tetralogy of Fallot?
Degree of pulmonary stenosis
What are the complications associated with Tetralogy of Fallot?
Cerebral thrombosis and ischaemia
Brain Abscess
Bacterial endocarditis
How does Tetralogy of Fallot present?
Cyanosis
Clubbing
Heart Failure
Failure to thrive
Dyspnoea on exertion - relieved by squatting
Ejection systolic murmur and loud S2 - third left intercostal space
Boot shaped heart on CXR
Why is dyspnoea relieved by squatting in Tetralogy of Fallot?
Squatting increases peripheral vascular resistance so reduces the Right to Left shunting
What does an ECG show in Tetralogy of Fallot?
Right axis deviation
Right ventricular hypertrophy
How are prolonged hypercyanotic spells managed?
Morphine - relieve pain and abolish hyperpnoea
Sodium bicarbonate IV - correct acidosis
Propranolol - peripheral vasoconstriction and relieve infundibular. Also prevent hypoxic spells
What is the definitive management for Tetralogy of Fallot?
Corrective Surgery for full repair - 6 months old
Prostaglandin infusion
What does corrective surgery for Tetralogy of Fallot entail?
Closure of VSD
Widening of the right ventricular outflow tract
Shunt between subclavian and pulmonary arteries to increase pulmonary blood flow (initial surgery)
What happens in transposition of the great arteries?
RV connect to aorta and LV connect to pulmonary artery creating 2 unconnected parallel circuits
What is required for transposition of the great arteries to be compatible with life?
Mixing of the circuits through ASD, VSD or PDA
Who is transposition of the great arteries more likely to affect?
Males
How does transposition of the great arteries present?
Within the first hours of life, the child has worsening cyanosis and severe hypoxia
May hear heart murmur if there is a septal defect (allow for life)
How is transposition of the great arteries managed in the immediate term?
Maintain body temperature
Correct any hypoglycaemia
Prostaglandin E1 infusion
Can do emergency cardiac catheter and therapeutic balloon atrial septostomy
Why is it important to maintain body temperature in transposition management?
Don’t want to worsen metabolic acidosis
Why do you give Prostaglandin E1 infusion in immediate management of transposition?
Reopen ductus arteriosus
What long term management is used for transposition of the great arteries?
Corrective surgery within 2 weeks - arterial switch procedure
What is hypoplastic left heart syndrome?
LV is small and non functional so RV maintains both pulmonary and systemic circulation
How does the Right Ventricle maintain the systemic circulation in hypoplastic left heart?
Via ASD or retrograde flow through PDA
How does hypoplastic left heart syndrome present?
Neonate becomes cyanosed with heart failure within days of birth
Blue-grey with weak pulses
How is hypoplastic left heart managed?
Palliative management or heart transplant
What is Ebstein’s anomaly?
Congenital heart defect characterised by low insertion of the tricuspid valve
How does a the heart of a child with Ebstein’s anomaly appear?
Large atrium and small ventricle
