Switch doc's... sounds too me like you need serveral opnions too make sure your getting the care u deserve.. I have a heart murmur and small one .. def not serious like yours.... but one day I almost stopped breathing and my heart was beating soo fast that it made me pass out... and by the time the ambulence got me too the hosptial .. it would stop beating so fast like it was and they would tell me they couldnt find anything! I did this for yrs.. bak and forth from feeling like I was going to die and then being fine when I got to the hospitial.. its tricky apparently too find heart problems.. but good luck and god bless.