Cyanotic heart defect

Cyanotic heart defect is a group-type of congenital heart defects (CHDs) that occurs due to deoxygenated blood bypassing the lungs and entering the systemic circulation or a mixture of oxygenated and unoxygenated blood entering the systemic circulation. It is caused by structural defects of the heart (i.e.:right-to-left, bidirectional shunting, malposition of the great arteries), or any condition which increases pulmonary vascular resistance. The result being the development of collateral circulation.

Signs and symptoms

• Clubbing
• The patient assuming a crouching position
• Cyanosis - facial discolouration (particularly the lips) and digit discolouration (fingers & toes).
• Crying
• Crabbiness/irritability
• Tachycardia
• Tachypnea
• A history of inadequate feeding.
• Unusually large toe & fingernails.
• Delayed development (both biological & psychological).

Categories/Classifications

• Tetralogy of Fallot (ToF)
• Total anomalous pulmonary venous connection
• Hypoplastic left heart syndrome (HLHS)
• Transposition of the great arteries (d-TGA)
• Truncus arteriosus (Persistent)
• Tricuspid atresia
• Interrupted aortic arch
• Pulmonary atresia (PA)
• Pulmonary stenosis (critical)
• Eisenmenger syndrome (reversal of shunt due to pulmonary hypertension) .
• Patent ductus arteriosus may cause cyanosis in late stage^[1]

Pharmacological Treatment & Management

• Morphine during Tet spells to decrease associated infundibular spasm.
• Prophylactic: Propranolol/Inderall
• Prostaglandin E (to keep the ductus arteriosus patent)
• Prophylactic antibiotic to prevent endocarditis
• Surgery: Glenn Shunt, Hemi-Fontan Procedure, Fontan Procedure. The purpose of these operations is to redirect the blood flow of the deoxygenated blood to the lungs by attaching the Superior Vena Cava directly to the Pulmonary Artery causing the blood that flows into the lungs to be oygenated before entering the chambers on the right side of the heart. Mathematical models are used to address the issue of pressure level alterations of circulation after the procedures. The pulmonary pressure resistance in the cavopulmonary connection is increased, and these models permit clear analyses of the pressure increase allowing doctors to avoid possible venous circulation congestion.

Non Cyanotic Heart Defects

Non cyanotic heart defects are more common because of higher survival. In these the shunt is initially from left (oxygenated) to right ( non oxygenated). These are

• Atrial septal defect
• Ventricular septal defect
• Coarctation of aorta (may cause cyanosis in some cases)
• Double outlet left/right ventricle

References