Congenital Cardiac Disease.  Ventricular septal defects (VSDs) have been reported as well as congenital mitral valve dysplasia.  The BTCA recommends that every puppy have a careful cardiac exam by a veterinarian prior going to its new home and that the pediatric cardiac form is submitted to OFA.  If a murmur is heard and if it persists beyond 14 weeks, we recommend that a cardiologist do an echocardiogram with the results submitted to OFA for the OPEN Database.  VSDs in Border Terriers have been known to close by the time a pup is 6 months old.  Great for the life of the dog, but not one you want to breed from.  Congenital cardiac disease appears to be complex inheritance.  The genetic basis is still unknown.