eMedicine Specialties > Emergency Medicine > Cardiovascular

Tetralogy of Fallot: Differential Diagnoses & Workup

Author: Mark Spektor, DO, Medical Director, Department of Emergency Medicine, Maimonides Medical Center
Coauthor(s): David A Donson, MD, Assistant Medical Director, Department of Emergency Medicine, Maimonides Medical Center; Kurt Pflieger, MD, FAAP, Active Staff, Department of Pediatrics, Lake Pointe Medical Center
Contributor Information and Disclosures

Updated: Dec 22, 2008

Differential Diagnoses

Acute Respiratory Distress Syndrome
Pediatrics, Foreign Body Ingestion
Anemia, Acute
Pediatrics, Pneumonia
Anemia, Sickle Cell
Pediatrics, Reactive Airway Disease
Aortic Stenosis
Pediatrics, Respiratory Distress Syndrome
Asthma
Pneumothorax, Iatrogenic, Spontaneous and Pneumomediastinum
Patent Ductus Arteriosus
Pulmonic Valvular Stenosis
Pediatrics, Apnea
Shock, Cardiogenic
Pediatrics, Bacteremia and Sepsis
Shock, Septic
Pediatrics, Bronchiolitis
Pediatrics, Crying Child

Other Problems to Be Considered

Ebstein malformation of the tricuspid valve
Pulmonary atresia
Ventricular septal defect
Pseudotruncus arteriosus

Workup

Laboratory Studies

  • Oximetry and arterial blood gases
    • Oxygen saturation is variable, but pH and pCO2 are normal unless the patient is in extremis, such as during a tet spell.
    • Oximetry is particularly useful in the dark-skinned patient or the anemic patient whose level of cyanosis is not apparent.
    • Cyanosis is not evident until 3-5 g/dL of reduced hemoglobin is present.
    • A decrease in systemic vascular resistance (SVR) during exercise, bathing, or fever potentiates a right-to-left shunt and precipitates hypoxemia.
  • Hematology
    • Prolonged cyanosis causes reactive polycythemia that increases the oxygen-carrying capacity.
    • Hyperviscosity and coagulopathy often ensue and are particularly deleterious in patients with a right-to-left intracardiac shunt.
    • Stroke and brain abscess are natural corollaries caused by paradoxical blood flow.

Imaging Studies

  • Chest roentgenography
    • Coeur en sabot (boot-shaped heart) secondary to uplifting of the cardiac apex from RVH and the absence of a normal main pulmonary artery segment (see Media file 2)
Uplifted apex and absence of pulmonary artery seg...

Uplifted apex and absence of pulmonary artery segment typifies the "coeur en sabot" (ie, boot-shaped heart) of tetralogy of Fallot.

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Uplifted apex and absence of pulmonary artery seg...

Uplifted apex and absence of pulmonary artery segment typifies the "coeur en sabot" (ie, boot-shaped heart) of tetralogy of Fallot.


    • Normal heart size due to the lack of pulmonary blood flow and congestive heart failure
    • Decreased pulmonary vascularity
    • Right atrial enlargement
    • Right-sided aortic arch (20-25% of patients) with indentation of leftward-positioned tracheobronchial shadow
    • May be normal in acyanotic TOF or may resemble findings of small- to moderate-sized VSD with mild RVH, right atrial enlargement, and increased pulmonary vascular markings
  • Echocardiography
    • Reveals a large VSD with an overriding aorta and variable degrees of RVOT obstruction

Other Tests

  • Electrocardiogram (see Media file 3)
    • Right axis deviation (+120° to +150°)
    • Right or combined ventricular hypertrophy
    • Right atrial hypertrophy
    • Partial or complete right bundle branch block - This is especially true of patients after surgical repair.
Typical preoperative ECG for tetralogy of Fallot.

Typical preoperative ECG for tetralogy of Fallot.

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Typical preoperative ECG for tetralogy of Fallot.

Typical preoperative ECG for tetralogy of Fallot.


Procedures

  • Cardiac catheterization
    • Assesses pulmonary annulus size and pulmonary arteries
    • Assesses the severity of RVOT obstruction
    • Locates the position and size of the VSD
    • Rules out possible coronary artery anomalies
  • Automatic internal cardiac defibrillator (AICD) placement
    • Recommended in patients with sustained ventricular tachycardia and those resuscitated after a sudden death event

More on Tetralogy of Fallot

Overview: Tetralogy of Fallot
Differential Diagnoses & Workup: Tetralogy of Fallot
Treatment & Medication: Tetralogy of Fallot
Follow-up: Tetralogy of Fallot
Multimedia: Tetralogy of Fallot
References
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References

  1. Senzaki H, Ishido H, Iwamoto Y, et al. Sedation of hypercyanotic spells in a neonate with tetralogy of Fallot using dexmedetomidine. J Pediatr (Rio J). Jul-Aug 2008;84(4):377-80. [Medline].

  2. Kantorova A, Zbieranek K, Sauer H, et al. Primary early correction of tetralogy of Fallot irrespective of age. Cardiol Young. Apr 2008;18(2):153-7. [Medline].

  3. Miatton M, De Wolf D, François K, et al. Intellectual, neuropsychological, and behavioral functioning in children with tetralogy of Fallot. J Thorac Cardiovasc Surg. Feb 2007;133(2):449-55. [Medline].

  4. Aboulhosn J, Child JS. Management after childhood repair of tetralogy of fallot. Curr Treat Options Cardiovasc Med. Dec 2006;8(6):474-83. [Medline].

  5. Anderson RH, Weinberg PM. The clinical anatomy of tetralogy of fallot. Cardiol Young. Feb 2005;15 Suppl 1:38-47. [Medline].

  6. Balaji S. Medical therapy for sudden death. Pediatr Clin North Am. Oct 2004;51(5):1379-87. [Medline].

  7. Goldmuntz E. The genetic contribution to congenital heart disease. Pediatr Clin North Am. Dec 2004;51(6):1721-37, x. [Medline].

  8. He GW. Current Strategy of Repair of Tetralogy of Fallot in Children and Adults: Emphasis on a New Technique to Create a Monocusp-Patch for Reconstruction of the Right Ventricular Outflow Tract. J Card Surg. Sep 5 2008;[Medline].

  9. Hövels-Gürich HH, Konrad K, Skorzenski D, et al. Long-term behavior and quality of life after corrective cardiac surgery in infancy for tetralogy of Fallot or ventricular septal defect. Pediatr Cardiol. Sep-Oct 2007;28(5):346-54. [Medline].

  10. Khairy P, Harris L, Landzberg MJ, et al. Implantable cardioverter-defibrillators in tetralogy of Fallot. Circulation. Jan 22 2008;117(3):363-70. [Medline].

  11. Kirklin JW, Barrett-Boyes BGF. Ventricular septal defect and pulmonary stenosis or atresia. Cardiac Surgery. 1993;2:861-1012.

  12. Nadas AS. Tetralogy of fallot. In: Nadas Pediatric Cardiology. Hanley & Belfus; 1992:471-93.

  13. Park MK. Tetralogy of fallot. In: Pediatric Cardiology for Practitioners. 3rd ed. Mosby-Year Book; 1996:168-75.

  14. Silverman NH. Tetralogy of fallot and related lesions. In: Pediatric Echocardiography. Lippincott Williams & Wilkins; 1992:195-214.

  15. Snider AR, Serwer GA. Defects in cardiac septation. In: Echocardiography in Pediatric Heart Disease. Mosby-Year Book; 1990:150-3.

  16. Tanel RE. ECGs in the ED. Pediatr Emerg Care. Jun 2007;23(6):428-9. [Medline].

  17. Woods WA, Schutte DA, McCulloch MA. Care of children who have had surgery for congenital heart disease. Am J Emerg Med. Jul 2003;21(4):318-27. [Medline].

  18. Zuberhuler JH. Tetralogy of Fallot. In: Heart Disease in Infants, Children and Adolescents. 2nd ed. 1995:998-1026.

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Further Reading

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Keywords

tetralogy of Fallot, TOF, Fallot tetrad, Fallot's tetrad, right ventricular outflow tract obstruction, congenital heart disease, maldevelopment of right ventricular infundibulum, subaortic ventricular septal defect, right ventricular infundibular stenosis, aortic valve positioned to override the right ventricle, right ventricular hypertrophy, right-to-leftshunting, cyanosis, hypertrophy of the infundibular septum, dyspnea, retarded growth, aortic ejection click, systolic thrill, systolic ejection murmur, clubbing, scoliosis, squatting position, retinal engorgement, hemoptysis, conotruncal abnormalities, DiGeorge syndrome, branchial arch abnormalities, fetal hydantoin syndrome, fetal carbamazepine syndrome, fetal alcohol syndrome, maternal phenylketonuria birth defects

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Contributor Information and Disclosures

Author

Mark Spektor, DO, Medical Director, Department of Emergency Medicine, Maimonides Medical Center
Mark Spektor, DO is a member of the following medical societies: American College of Emergency Physicians, American College of Physician Executives, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Coauthor(s)

David A Donson, MD, Assistant Medical Director, Department of Emergency Medicine, Maimonides Medical Center
David A Donson, MD is a member of the following medical societies: American College of Emergency Physicians and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Kurt Pflieger, MD, FAAP, Active Staff, Department of Pediatrics, Lake Pointe Medical Center
Kurt Pflieger, MD, FAAP is a member of the following medical societies: American Academy of Pediatrics, American College of Emergency Physicians, American Heart Association, and Texas Medical Association
Disclosure: Nothing to disclose.

Medical Editor

Theodore J Gaeta, DO, MPH, FACEP, Clinical Associate Professor, Department of Emergency Medicine, Joan and Sanford Weill Medical College at Cornell University; Vice Chairman and Program Director of Emergency Medicine Residency Program, Department of Emergency Medicine, New York Methodist Hospital; Academic Chair, Adjunct Professor, Department of Emergency Medicine, St George's University School of Medicine
Theodore J Gaeta, DO, MPH, FACEP is a member of the following medical societies: American College of Emergency Physicians, Council of Emergency Medicine Residency Directors, New York Academy of Medicine, New York Academy of Medicine, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Gary Setnik, MD, Chair, Department of Emergency Medicine, Mount Auburn Hospital; Assistant Professor, Division of Emergency Medicine, Harvard Medical School
Gary Setnik, MD is a member of the following medical societies: American College of Emergency Physicians and National Association of EMS Physicians
Disclosure: Intellicare Salary Management position; South Middlesex EMS Consortium Salary Management position

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

David FM Brown, MD, Assistant Professor, Department of Medicine, Division of Emergency Medicine, Harvard Medical School; Associate-Chief, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital
David FM Brown, MD is a member of the following medical societies: American College of Emergency Physicians and Society for Academic Emergency Medicine
Disclosure: Schering  Honoraria Speaking and teaching

 
 
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