Patofisiologi TOF

• Bila pada bayi dapat kita jumpai asianosis itu dapat disebabkan aliran ventrikel left – to-right shunt sehingga volume darah di ventrikel kanan meningkat dan akhirnya menyebabkan kontraksi yang meningkat pada ventrikel kanan ventrikel kanan hipertropi.

• ventrikel kanan hipertropi dan duktus arteriosus yang menutup right – to- left- shunt sianosis

• Figure 1 Physiology of the tetralogy of Fallot. Circled numbers represent oxygen saturation values. The numbers next to the arrows represent volumes of blood flow (in L/min/m2). Atrial (mixed venous) oxygen saturation is decreased because of the systemic hypoxemia. A volume of 3 L/min/m2 of desaturated blood enters the right atrium and traverses the tricuspid valve. Two liters flows through the right ventricular outflow tract into the lungs, whereas 1 L shunts right to left through the ventricular septal defect (VSD) into the ascending aorta. Thus, pulmonary blood flow is two thirds normal (Qp : Qs [pulmonary-to-systemic blood flow ratio] of 0.7 : 1). Blood returning to the left atrium is fully saturated. Only 2 L of blood flows across the mitral valve. Oxygen saturation in the left ventricle may be slightly decreased because of right-to-left shunting across the VSD. Two liters of saturated left ventricular blood mixing with 1 L of desaturated right ventricular blood is ejected into the ascending aorta. Aortic saturation is decreased, and cardiac output is normal.

• Mekanisme kompensasi akibat stenosis pulmoner adalah penggunaan duktus arteriosus sebagai jalur alternatif yang menghubungkan aorta dengan pulmonalis, selain itu juga bisa melalui MAPCAs ( Major AortaPulmonary Collateral Arteries)

ATP turun

Degradasi adenosin

Inosin, xanthin, hipoxantihn dan asam urat

Patofisiologi clubbing finger

• Hipoksia eritropoetin megakariosit ( membentuk platelet dalam sitoplasma dengan cara fragmentasi) pulmoner sitoplasma megakariosit juga mengandung banyak growth factor (platelet derived growth factor and transforming growth factor β R- L shunt sistemik kapiler di jari – jari tangan melepaskan Growth Factor clubbing finger