It doesn't seem to be a problem for the ones afflicted, in fact many don't even know they have it until they need medical attention, leading perfectly healthy and normal lives. The condition is called, Situs inversus imaging, which means "inverted position of the internal organs." Leonardo da Vinci knew about it and drew it.
One such person with the condition is our very own Canadian actress, SCTV's Catherine O'Hara. Her organs sit in her chest and abdomen in a perfect mirror-image of how they are normally positioned in most of us.
It only becomes a concern if you need an organ transplant and the only available organ is taken from someone with their heart facing the wrong way called, 'Dextrocardia.' It would be like fitting a square into a circle, it just wouldn't fit.
Or say, you are rushed to the emergency with appendicitis, you tell them where it hurts and they surgically go in to remove the damaged organ, but they don't find one. It's on your other side.
See what I mean. It could be a problem.