How could doctors miss my papvr for 25 years i have had 4 cts of the chest and 10 echos and no 1 picked this up until 1 week ago at the mayo clinic...

Could be: That the tapvr is subtle. It can be a very difficult call to make on echo. On ct the issue can be the same.

Mild abnormality: It is unusual to have had 10 echocardiograms at your age, so an abnormality may have been suspected. However, partial anomalous pulmonary venous return is often small in amount and is often asymptomatic. While an MRI would have confirmed the diagnosis, if you had no symptoms, your doctors may have considered periodic monitoring to be a reasonable course.