Tetralogy of Fallot (TOF) in Adults Clinical Presentation

Updated: Nov 13, 2018
  • Author: Shabir Bhimji, MD, PhD; Chief Editor: Yasmine S Ali, MD, FACC, FACP, MSCI  more...
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Presentation

History

The clinical presentation of infants with tetralogy of Fallot (TOF) is included for comparison to that of adults.

Presentation of pediatric patients with tetralogy of Fallot

Most infants with tetralogy of Fallot have difficulty with feeding, and failure to thrive (FTT) is commonly observed. Infants with pulmonary atresia may become profoundly cyanotic as the ductus arteriosus closes unless bronchopulmonary collaterals are present. Occasionally, some children have just enough pulmonary blood flow and do not appear cyanotic; these individuals remain asymptomatic, until they outgrow their pulmonary blood supply.

At birth, some infants with tetralogy of Fallot do not show signs of cyanosis, but they may later develop episodes of bluish pale skin during crying or feeding (ie, "Tet" spells). Hypoxic tet spells are potentially lethal, unpredictable episodes that occur even in noncyanotic patients with tetralogy of Fallot. The mechanism is thought to include spasm of the infundibular septum, which acutely worsens the right ventricular (RV) outflow tract obstruction (RVOTO). These spells can be aborted with relatively simple procedures.

A characteristic fashion in which older children with tetralogy of Fallot increase pulmonary blood flow is to squat. Squatting is a compensatory mechanism, of diagnostic significance, and highly typical of infants with tetralogy of Fallot. Squatting increases peripheral vascular resistance (PVR) and thus decreases the magnitude of the right-to-left shunt across the ventricular septal defect (VSD). Exertional dyspnea usually worsens with age. Occasionally, hemoptysis due to rupture of the bronchial collaterals may result in the older child.

The rare patient may remain marginally and imperceptibly cyanotic, or acyanotic and asymptomatic, into adult life.

Cyanosis generally progresses with age and outgrowth of pulmonary vasculature and demands surgical repair. The following factors can worsen cyanosis in infants with tetralogy of Fallot:

  • Acidosis

  • Stress

  • Infection

  • Posture

  • Exercise

  • Beta-adrenergic agonists

  • Dehydration

  • Closure of the ductus arteriosus

The predominant shunt is from right to left with flow across the VSD into the left ventricle (LV), which produces cyanosis and an elevated hematocrit value. When the pulmonary stenosis is mild, bidirectional shunting may occur. In some patients, the infundibular stenosis is minimal, and the predominant shunt is from left to right, producing what is called a pink tetralogy. Although such patients may not appear cyanotic, they often have oxygen desaturation in the systemic circulation.

Symptoms generally progress secondary to hypertrophy of the infundibular septum. Worsening of the RVOTO leads to RV hypertrophy, increased right-to-left shunting, and systemic hypoxemia.

Presentation of the adult with tetralogy of Fallot

The clinical features of tetralogy of Fallot (TOF) in the adult are directly related to the severity of the anatomic defects. 

Even after surgery it is important to understand that despite the curative approach to surgery, it is simply a long-term palliative procedure. The surgery only corrects the anatomic abnormality; it does not address the cause and does not prevent the ongoing anatomic changes in the RV and pulmonary vessels. Hence, sooner or later, most patients with corrective surgery will present with some type of symptom related to dysfunction of the RV and RVOTO. [21]

The majority of patients with repaired tetralogy of Fallot remain symptom free for at least the first two decades following the initial surgery. Mild pulmonary valve insufficiency may appear after the second decade of life and is often asymptomatic. However, with time, the pulmonary valve insufficiency become severe and patients do become symptomatic. Chief complaints at that time may include lack of exercise endurance, palpitations, and a gradual decline in bodily functions.

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Physical Examination

As tetralogy of Fallot (TOF) progresses in adults, exertional dyspnea, syncope, palpitations, and evidence of right heart failure such as elevated jugular venous pressure (JVP), ascites, peripheral edema, and hepatomegaly may be noted. Closer examination may also reveal the presence of a large "A wave" in the JVP tracing. This A wave occurs as a result of atrial contraction in late diastole; an abnormally large A wave is typically visible to the eye and denotes increased resistance to right atrial emptying as a result of right ventricular (RV) hypertrophy, which can be seen in severe pulmonary stenosis.

Auscultation

Auscultation of the chest for pulmonary valve insufficiency will reveal a low-pitched, short diastolic murmur. This murmur is often difficult to hear in most individuals as it has a very short duration, even when the insufficiency is severe; thus the pathology may be missed on the physical examination. Some patients may have an extra heart sound—an ejection click as a result of a dilated ascending aorta. In addition, some patients may have a murmur due to aortic regurgitation.

If RV outflow tract obstruction is present, an audible murmur is usually noted. In addition, the presence of a residual ventricular septal defect will reveal a loud pansystolic murmur.

If the pulmonary valve insufficiency is not identified, it gradually leads to RV dysfunction and the onset of arrhythmias. The majority of adult patients with tetralogy of Fallot need corrective surgery to repair or replace the pulmonary valve.

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