Heart Murmur - cause for concern?

[RDCARRIE@aol.com]

Since we're discussing horse hearts (arrhythmia), thought I'd ask about heart 
murmurs.  At a ride last weekend (LD), the vet asked me at the halfway point 
if I realized my horse had a heart murmur.  He said it wasn't real bad, just 
a slight "whoooosh".  He didn't seem too concerned about it, and said that 
some horses exhibit one during rides.  We hadn't been going fast (finished in 
4:04, I think, and horse had plenty of energy left), temps were moderate, 
horse was already at criteria as I arrived at the vet check both at the half 
way and end.  This vet has vetted my horse at rides before and never noticed 
anything, so I wonder if it's just an occasional thing?  When we P&Red at the 
end of the ride the person doing his P&R also noticed the murmur.  Is this 
something I should get checked out further, such as taking him to Texas A&M 
for a complete exam?  He's a 15 yr old Arab.  Forgot to ask the folks I 
bought him from if they'd ever noticed it...will try to do that this week.

Thanks,
Dawn in East Texas