Left untreated, tetralogy of Fallot rapidly leads to progressive right ventricular hypertrophy due to increased resistance caused by narrowing of the pulmonary trunk. This results in heart failure that begins in the right ventricle and often leads to left ventricular failure and dilated cardiomyopathy.
Why is there right ventricular hypertrophy in tetralogy of Fallot?
Right ventricular hypertrophy is secondary to high right ventricular (RV) pressure resulting from pulmonary stenosis and large VSD. In extreme cases, the right ventricular outflow tract is completely blocked, resulting in tetralogy of Fallot with pulmonary atresia.
Why is there polycythemia in tetralogy of Fallot?
Polycythemia can occur secondary to myeloproliferative disorders (eg, polycythemia vera) or more commonly as a result of a nonclonal increase in the number of erythropoietin (SP)-regulated red blood cells. SP has acquired and congenital subtypes [1].
What Causes Cyanosis in Tetralogy of Fallot?
The cause of cyanosis is below the normal level of oxygen in the blood. Patients with tetralogy of Fallot are at risk for cyanosis because the narrowing of blood flow to the lungs combined with a VSD or hole allows blood to bypass the lungs and go directly to the body in many cases.
What is the most common complication in patients with tetralogy of Fallot?
Ventricular arrhythmias are more common and would be the leading cause of late postoperative death. Sudden death due to ventricular arrhythmias was reported in 0.5% of patients within 10 years after repair.