What is the pathophysiology of tetralogy of Fallot (TOF) in adults?

Updated: Nov 13, 2018
  • Author: Shabir Bhimji, MD, PhD; Chief Editor: Yasmine S Ali, MD, FACC, FACP, MSCI  more...
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Previously, clinicians often ordered routine echocardiograms in adult patients with tetralogy of Fallot who were followed in the clinic following surgery in infancy. At that time, it was felt that, as in cases of tricuspid regurgitation, pulmonary valve insufficiency was a relatively benign and inconsequential observed entity. Because most affected patients were not symptomatic, they were never treated. However, observation of these patients over time revealed that they began to develop severe RV dysfunction and arrhythmias. The RV dilatation from the pulmonary valve insufficiency is associated with fibrosis and severe myocardial damage, which then often lead to a decrease in exercise endurance, and the majority of patients soon develop ventricular arrhythmias. [14]

Initially most patients with chronic RV function are asymptomatic, but as the compensatory mechanisms fail and the ejection fraction decreases, symptoms start to appear. If the condition is not treated at this stage, the RV dysfunction is irreversible. The arrhythmias occur as a result of progressive dilatation and stretching of the right atrium and RV.

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