The pericardium is incised and opened horizontally 2 cm above the phrenic nerve and suspended with stay sutures. Blunt dissection is carried out between the superior vena cava and the right superior pulmonary vein, until transverse pericardial sinus is reached. The oblique pericardial sinus is exposed after dissecting in the same manner the space between the inferior vena cava and the right inferior pulmonary vein. Lastly, the Waterson groove is dissected.