Finley Mae, is 6 weeks old, she is presenting with her mother to newborn followup clinic. You are the paediatric intern in the clinic today.
Finley's mother informs you that she has been feeding and sleeping well, but she is concerned that occasionally Finley appears short of breath when breast feeding.
You note that Finley is alert and pink and there are no features of respiratory distress.
On auscultation you detect a high pitched pansystolic cardiac murmur along the left sternal edge.
General:
Specific:
Cardiac failure in infancy tends to be dominated by pulmonary congestion, which leads to dyspnoea/tachypnoea.
Dyspnoea contributes to feeding difficulties, reduced intake and increased metabolic rate. Failure to thrive often results. Chronic dyspnoea may lead to the appearance of Harrison's sulci, which are deformations of the ribcage at the site of the diaphragmatic attachments. Crepitations at the lung bases are usually a manifestation of superimposed infection rather than heart failure in infants.
Systemic venous congestion is manifest by liver enlargement and/or oedema. Liver engorgement results in an enlarged, abnormally firm liver with its edge palpable 2.5-5 cm below the costal margin. In infants, oedema is often diffuse and difficult to detect. It is often best seen around the face and eyes (periorbital oedema).
Elevated jugular venous pressure cannot be assessed easily in infancy.
Other evidence of cardiac failure may include persistent tachycardia, a chronic dry cough and profuse sweating, especially of the forehead and scalp.
Ventricular Septal Defect (VSD) comprises around 30% of all cardiac defects. They vary from tiny defects, of pinhole size, to huge defects. Small defects are more common than large ones and are usually asymptomatic.
A VSD is a hole in the wall (septum) between the two lower chambers of the heart (ventricles). It develops due to incomplete formation during embryological development. This creates a left-to-right shunt, where oxygenated blood from the left ventricle flows back into the right ventricle, leading to increased blood flow to the lungs.
With small defects, the chest X-ray and electrocardiogram (ECG) are frequently normal. With larger defects, the X-ray shows cardiomegaly and increased pulmonary vascular markings. The ECG often shows biventricular hypertrophy.
Natural History:
The natural history of a VSD varies. Small defects frequently undergo spontaneous closure, which may occur in 50% or more. Some moderate defects may also diminish in size and the shunt becomes minor.
Complications:
Important complications include progressive aortic incompetence, when one leaflet of the aortic valve is sucked into (prolapses) into an adjacent VSD, or the development of infundibular pulmonary stenosis.
Small isolated defects may be left alone if the evidence shows no significant haemodynamic disturbance and the patient remains symptom-free.
Large VSDs are associated with a variable degree of pulmonary hypertension. Pulmonary 'hypertension' is present from birth and may lead to the development of pulmonary vascular obliterative disease. Progression of pulmonary vascular damage, with increasing vascular resistance in the pulmonary circulation, will eventually result in reversal of the shunt, with the appearance of cyanosis (Eisenmenger syndrome), developing in adolescence or early adult life.
Overview of Left-to-Right Shunts:
Left-to-right shunts (such as ASD, VSD, and patent ductus arteriosus (PDA)) increase pulmonary blood flow and are not initially associated with cyanosis. However, left-to-right shunts raise both flow volumes and pressures in the normally low-pressure, low-resistance pulmonary circulation, which can lead to right ventricular hypertrophy and pathological changes in the pulmonary vasculature. Eventually, pulmonary vascular resistance approaches systemic levels, thereby producing a new right-to-left shunt that introduces unoxygenated blood into the systemic circulation (Eisenmenger syndrome).
Persistent Ductus Arteriosus:
The ductus arteriosus is a normal vascular channel during intrauterine life. It is a large vessel with a muscular wall which courses between the pulmonary artery and the aorta. The ductus arteriosus normally closes within the first 48 hours of life. If it remains patent longer than this it is unlikely to close spontaneously. The exception is in premature babies where closure should occur by roughly the expected due date.
Atrial Septal Defect:
An atrial septal defect (ASD) is an abnormal, fixed opening in the atrial septum caused by incomplete tissue formation that allows communication of blood between the left and right atria. ASDs are often asymptomatic in childhood. A small number will be importantly symptomatic in the first year of life and they are generally repaired before the age of 5.
Aortic Stenosis:
Aortic valve stenosis may be congenital or acquired. The congenital lesions are associated with thickening of the leaflets and variable fusion between the cusps producing most commonly a functionally bicuspid valve. The degree of stenosis varies from very mild (which may be asymptomatic well into adulthood) to severe, producing heart failure in the newborn period.
Pulmonary Stenosis:
This relatively frequent malformation constitutes an obstruction at the pulmonary valve, which may be mild to severe. Right ventricular hypertrophy often develops. Mild stenosis may be asymptomatic and compatible with long life, whereas more severe cases warrant intervention, which is usually balloon dilatation.
Coarctation of the Aorta:
Coarctation (narrowing, constriction) is an obstruction of the aorta usually just proximal to the ductus arteriosis, beyond the left subclavian artery. Males are affected twice as often as females, although females with Turner syndrome frequently have a coarctation. Although coarctation of the aorta may occur as a solitary defect, it is accompanied by a bicuspid aortic valve in 50% of cases and may also be associated with congenital aortic stenosis, ASD, VSD, mitral regurgitation, or berry aneurysms of the circle of Willis in the brain.