Tetralogy of Fallot Jimmy Wang Childrens Memorial Hospital

Tetralogy of Fallot Jimmy Wang Children’s Memorial Hospital November 2, 2007

Tetralogy § Comes from Attic Theater in Greece § A compound work made up of 4 distinct works, intended to be viewed in one sitting § Duology, Trilogy, Pentalogy, Heptalogy

Famous Tetralogies § Literature: Shakespeare’s Richard II, Henry IV, Henry VI § Movies: Lethal Weapon, Die Hard, Jaws, Austin Powers, Indiana Jones (2008), Rambo (2008), Terminator (2009), Shrek (2010) § Medicine: Tetralogy of Fallot Shrek 4 in 2010

Dr. Etienne Fallot § Initially described in 1672 by Danish anatomist, paleontologist, and geologist, Niels Stensen § Named after French physician Etienne-Louis Niels Stensen Arthur Fallot in 1888, who accurately described the 4 anatomic abnormalities in TOF Dr. Etienne Fallot, 1850 -1911

4 Characteristics in TOF § VSD § Right ventricular outflow tract obstruction § Overriding aorta § Right ventricular hypertrophy Radiographics 2007; 27: 1323 -1334.

Tetralogy of Fallot http: //commons. wikimedia. org/wiki/Image: Tetralogy_of_Fallot. svg

RV Outflow Obstruction § Spectrum of outflow obstruction § 45% stenosis at RV infundibulum § 10% stenosis at pulmonic valve § 30% combination of PV and infundibular stenosis § 15% atresia of the pulmonic valve § Hypoplasia of the pulmonary annulus and main PA

Ventricular Septal Defect § Perimembranous defect (involving fibrous base of the pulmonic valve) § Extends to subpulmonic region § Needs to be large enough to equalize pressures in R and L heart

Overriding Aorta & RVH § Overriding aorta can be variable § RVH develops secondarily to long standing elevated RV pressures and increased stroke volume from RV outflow obstruction

Etiology/Prevalence § Caused by anterior malalignment of the conal septum, with underdevelopment of the infundibulum § Most common cyanotic congenital heart defect in children beyond infancy (10%) § 4 -8% of all congenital cardiac lesions § 3 -6 cases per 10, 000 live births

Associations § Stenosis or obstruction at the origin of the L pulmonary artery in 40% § Right aortic arch in 25% § ASD in 5% § Abnormal coronary arteries in 5% § Most common: aberrant origin of the anterior descending artery from the right coronary artery, crosses RV outflow tract (potential surgical disaster)

Clinical Presentation § Spectrum ranges from acyanotic TOF/pink Fallot § § § (with L to R shunt) to classic Fallot to severe cyanosis in pulmonary atresia with VSD Most patients p/w cyanosis at or shortly after birth Milder cases may present later with SOB on exertion with relief in squatting position “Tet spells” – paroxysm of hyperpnea, irritability, crying, & cyanosis, requires immediate medical attention, may lead to convulsion, CVA, or death

Physical Exam § Cyanosis, tachypnea, clubbing § Auscultation: heart murmur usually audible at birth - single S 2, long cresendodecresendo systolic murmur at mid & LUSB (usually grade 3 -5/6), also with holosystolic regurgitant murmur of VSD

Chest Radiograph in TOF § Heart size ranges from § § slightly small to slightly large Decreased pulmonary vascular markings Superiorly turned cardiac apex – boot shaped heart R atrial enlargement Concavity of the PA segment Radiographics 2007; 27: 1323 -1334.

Medical Management § Treat hypoxic “Tet” spells (positioning, morphine, oxygen, sodium bicarbonate, phenylephrine, ketamine, propranolol) § Oral propranolol (prevent hypoxic spells) § Balloon dilatation of RV outflow tract & PV to delay surgical repair § Antibiotic prophylaxis against SBE

Palliative Shunt Placement § Indications for shunt vs. surgical repair vary between institutions, usually done for more complicated cases (TOF with pulmonary atresia, severely cyanotic <3 months, severe hypoxic spells) § Goal: increase pulmonary blood flow § Classic Blalock-Taussig shunt, Gore-Tex interposition shunt: anastomotic shunt between subclavian artery & ipsilateral PA

Correctional Surgical Intervention § Patch closure of VSD & widening of RV outflow tract § Symptomatic: variable between institutions, after 3 months of age preferred, increased mortality in pts <3 months § Mildly cyanotic: 3 -24 months of age § Asymptomatic/Acyanotic: 1 -2 years of age www. inova. com

TOF with Absent Pulmonary Valves § § § Occurs in 2% of patients with TOF Absent PV or irregular rudimentary PV leaflets Stenotic PV annulus less severe than classic TOF – results in bidirectional shunting through VSD (predominantly L to R, mild cyanosis evolves into CHF after newborn period) § Massive pulmonary artery aneurysmal dilatation from severe pulmonary regurgitation § Massive PA compresses lower central airways => hypoplasia, post-obstructive complications (PNA, atelectasis), usual cause of death

Absent Pulmonary Valves § Dilated main PA and hilar PA’s § Hyperinflated lungs from central airway obstruction § Slightly increased pulmonary vascular markings to diffuse bilateral opacification of CHF from L to R shunting

D. R. - 12 year old male § History of Tetrology of Fallot with absent pulmonary valves § Surgical history: surgical repair on 6 th day of life in 1995, had RV to PA conduit revision in 1997 § Now p/w increasing fatigue and dyspnea following strenuous exercise (basketball, football)

Gated FIESTA Axial

Post-gad

RV FIESTA Short Axis

FIESTA 4 chamber view

References § 1. Boechat MI, Ratib O, Williams PL, et al. Cardiac MR Imaging and MR Angiography for Assessment of Complex Tetralogy of Fallot and Pulmonary Atresia. Radiographics 2005; 25: 1535 -1546. § 2. Ferguson EC, Krishnamurthy R, Oldham SA. Classic Imaging Signs of Congenital Cardiovascular Abnormalities. Radiographics 2007; 27: 13231334. § 3. Park MK. Pediatric Cardiology, 4 th Edition. St. Louis, Mosby, Inc 2002, pp. 189 -200. § 4. Westra, SJ. “Tetralogy of Fallot, ” [Online] Available https: //my. statdx. com. Stat. Dx 2007.