My 8 month old baby has a heart murmur, he didn't have it on his first 6 months, the pediatrician told me to take my baby to a cardiologist, is my baby at risk of major heart disease? he looks very healthy?

The major heart defects that are quite worrisome are evident either at birth or by 2-4 months of age. Murmurs are just the extra sound made when fluid moves around or through a structure that produces a change in the flow. Murmur bad=usually near birth, murmur that may self heal or be fixed shows up later. Get the consult. Your worry is appropriate, but I would not go to a dark place. Likely okay.