How can a cardiologist insert a catheter into a patient’s right femoral artery and then see the heart?

Cardiologists routinely access the arterial vessels at the top of either leg, the femoral artery, or from the arm, the radial artery. From here the catheter or a guide wire is then fed through the arterial circulation into the heart. Just above the heart catheters are changed over a wire to access the left and right coronary arteries and the left ventricle.