4 weeks ago I took my puppy "Leo" to the Vet. She said he had a grade/level 3 heart murmur. Today , 10-24-2012 he went back for check ups - shoots. Now he has a grade 6 heart murmur. It took 4 weeks for his heart to get to 6. How much time do I have? Could he still live for years with this, or is he running out of time? I do not know what to think, I'm beside myself , thinking of "What to expect" I know that no one can say how long, but does anyone know , or would give me advice ? Thank you