Cardiology 3 Flashcards
What are duct dependent lesions?
Coarctation of aorta TGA- transposition of great vessels HLHS- hypoplastic left heart syndrome PA- pulmonary atresia TA- tricuspid atresia
What are the features of pulmonary atresia?
Pulmonary valve fails to develop and completely blocks the outflow of blood from the heart to the lungs
When born the only thing providing oxygen to the lungs is the ductus arteriosus
Baby will turn blue rapidly
What are the features of tricuspid atresia?
Blood flow is blocked from passing from the right atrium to the right ventricle
Only left ventricle is effective (right small and non-functional)
Mixing of systemic and pulmonary venous return in the left atrium
A child must have ASD or VSD to survive
Cyanosis if duct dependent or become cyanosed and breathless later
How are duct dependent lesions treated?
Restore the duct via a prostaglandin (E) infusion (short term)
Formaldehyde should be infiltrated into the structure for the longer term
What is seen on an ECG in supraventricular tachycardia?
Narrow complex tachycardia
If HF severe, myocardial ischameia changes, T wave inversion in lateral leads
Wolff-Parkinson-White- short PR interval and a delta wave
What is the management for children with supraventricular tachycardia?
Tissue acidosis corrected- positive pressure ventilation if required
Vagal stimulation manoeuvres- carotid sinus massage or cold ice pack to face (80% successful)
IV adenosine (gold standard)- given incrementally in increasing doses
Electrical cardioversion with a syncronised DC shock if adenosine fails
Once sinus rhythm restored- flecainide or sotalol (maintenance therapy)
Digoxin can be used on its own if no delta wave
Those who relapse are treated with percutaneous radiofrequency ablation or cryoablation of the accessory pathway
What can cause myocarditis?
Infections- coxsackie B or EBV
Kawasaki disease
Adriamycin
SLE, RA, rheumatic fever or sarcoidosis
How is myocarditis diagnosed?
Histology from a percutaneous endomyocardial biopsy
Echo- poor ventricular function
CXR- cardiomegaly
ECG- reduced QRS complex size
What predisposes children to getting endocarditis?
PDA or VSD Coarctation of aorta Previous rheumatic fever B-haemolytic Streptococcus viridans (50%) S. aureus Group D streptococcus (lower Gi surgery)
What is the management for bacterial endocarditis?
High dose IV penicillin/vancomycin for >6 weeks
Bed rest and HF should be treated
Surgery to remove infected prosthetic material
What are the acyanotic causes of congenital heart disease?
ventricular septal defects (VSD) - most common, accounts for 30% atrial septal defect (ASD) patent ductus arteriosus (PDA) coarctation of the aorta aortic valve stenosis
What are the cyanotic causes of congenital heart disease?
tetralogy of Fallot
transposition of the great arteries (TGA)
tricuspid atresia
HLHS
What are the 4 charcateristic features of tetralogy of fallot?
VSD
Right ventricular hypertrophy
Right ventricular outflow tract obstruction, pulmonary stenosis
overriding aorta
What is patent ductus arteriosus common in?
Usually closes in first few breaths (increased pulmonary flow, enhances prostaglandins clearance)
Premature babies
Babies born at high altitude
Maternal rubella infection at first trimester
What is the management for patent ductus arteriosus?
Indomethacin (inhibits prostaglandin synthesis)
Prostaglandin E1 useful to keep duct open until surgical repair
