TETRALOGY OF FALLOT (TOF) Mary Beth Sanders BSN & Laura Durbin BSN East Carolina University College of Nursing, Greenville, North Carolina

Incidence and Risk occurs in 3 of every 10,000 live births. most common cause of cyanotic cardiac disease in patients beyond the neonatal age accounts for up to one-tenth of all congenital cardiac lesions There are a number of state-based programs monitoring CHDs among newborns and young children, but currently no population-based tracking system exists to look at this growing population of older children and adults with heart defects. It is the least diagnosed CHD during the prenatal period. Factors that increase the risk for this condition during pregnancy include: Alcoholism in the mother Diabetes Mother who is over 40 years old Poor nutrition during pregnancy Rubella or other viral illnesses during pregnancy Maternal intake of retinoic acid in 1 st trimester Associated conditions trisomies 21, 18, 13 microdeletions of chromosome 22 DiGeorge Syndrome. 3% risk of recurrence in a family

Surgical Treatment of TOF Primary Repair VSD is closed widening of the pulmonary valve or artery to increase pulmonary blood flow. Pulmonary regurgitation is a complication patching to pulmonary artery. Severe cases may need pulmonary valve replacement Ventricular arrhythmia is the most common long term complication of repair Blalock-Taussig procedure (temporary procedure) surgical construction of a shunt between the right subclavian artery and the right pulmonary artery as a temporary measure to increase pulmonary blood flow to the lungs. Can be used as a palliative procedure to establish pulmonary blood flow prior to primary repair.

Prostaglandin E (PGE) Stabilizes infants with severe cyanosis by reopening or maintaining the ductus arteriosus In most infants, the ductus will reopen within 30 minutes to 2 hours after starting PGE 1 Administered as a continuous IV infusion at ug/kg/min. Side effects include Refractory hypotension from vasodilation Apnea Hyperthermia/ Flushing Seizures Pharmacology Prostaglandins are long chain unsaturated fatty acids produced by the action of the enzyme clooxygenase and are classified into groups E,D,A, F & B PGE is also produced in the kidney in response to decreased renal blood flow  prevents vasoconstriction and renal ischemia PGE vasodilates all arterioles, inhibits platelet aggregation, and stimulates uterine and intestinal smooth muscles.

Physiology of TOF Four Different Defects In TOF large ventral septal defect: An opening between the 2 bottom chambers of the heart. Pulmonary valve stenosis or atresia: Pulmonary blood flow obstruction. This is due to a narrowing at the pulmonary valve or the pulmonary arteries. Right ventricular hypertrophy: Caused by the heart working harder to pump blood through the body because of the narrow pulmonary valve. Overriding aorta: The aorta overrides the ventral septal defect.

Tetralogy of Fallot Pink TOF Mild outflow tract obstruction Blood is shunted from left to right. Blood is able to enter the pulmonary system thus, it is oxygenated. Infant is “pink”. Infants and children can experience TET spells. Surgical repair is between 18 months and 3 years old. Blue TOF Severe outflow tract obstruction is present. Blood is shunted from right to left. Pulmonary blood flow is dependent upon R to L shunting through the PDA. Infant will require PGE until surgical repair is undertaken.

Radiographic Findings in TOF Classic boot-shaped heart This finding is a result of the upward lifting of the apex of the heart. This is due to the hypertrophy of the right ventricle. The more pronounced the upward lifting, the greater the outflow obstruction is.

Blood Flow in Infants with Tetralogy of Fallot Narrowing of the right ventricular outflow tract at the pulmonary artery. Deoxygenated blood is prevented from entering pulmonary system. Right ventricle hypertrophies attempting to push blood through stenosis. VSD allows shunting left to right in mild stenosis “ pink” TET

Blood flow in infants with Tetralogy of Fallot Cyanosis occurs when the right tract outflow obstruction impedes the blood flow significantly. Blood in the right ventricle takes the path of least resistance into the left ventricle. This creates a right-to-left shunt Blood is directed away from the pulmonary system Blood leaves heart before being oxygenated. Thus, the infant is cyanotic.

References Bailliard, F., & Anderson, R. H. (2009, January 13). Tetralogy of Fallot. Orpanet journal of rare diseases, 4. Buck, M. L. (2000). Alprostadil (pge1) for maintaining ductal patency. Pediatric Pharmacotherapy, 6. Retrieved from Ferguson, E. C., Krishnamurthy, R., & Oldham, S. A. (2007). Classic imaging signs of congenital cardiovascular abnormalities. RadioGraphics, 27, Ismail, S. R., Kabbani, M. S., Najm, H. K., Abusuliman, R. M., & Elbarbary, M. (2010, April ). Early outcome of tetralogy of fallot repair in the current era of management. J Saudi Heart Association, 22(2), Quek, S. C., & Lee, C. N. (2010). The modified blalock-taussig shunt revisited. Cardiology in the Young, 20,

References Martínez, J., Gómez, O., Bennasar, M., Olivella, A., Crispi, F., Puerto, B., & Gratacós, E. (2010). The 'question mark' sign as a new ultrasound marker of tetralogy of Fallot in the fetus. Ultrasound In Obstetrics & Gynecology, 36(5), doi: /uog.7614 Westmoreland, D. (1999). Critical congenital cardiac defects in the newborn. Journal Of Perinatal & Neonatal Nursing, 12(4),

References Scholz, T. D., & Reinking, B. E. (2012). Congenital heart disease. In Avery’s diseases of the newborn (9th ed., pp ). Phildelphia, PA: Elsevier U.S. National Library of Medicine website. (2011). Westmoreland, D. (1999). Critical congenital cardiac defects in the newborn. Journal Of Perinatal & Neonatal Nursing, 12(4),