Feel sick with dizziness and nausea after any physical exertion

Hi , two years ago I was ill and had chest pains, I went to the doc and I was diagnosed with a mild case of marfan syndrome , which is a weak connective tissue disorder, ever since then I've been admitted into hospital every 5months or so , because of dizziness, nausea, vomiting, and racing blood pulse, these symptoms usually start acouple of hours after any type of physical exertion , carrying heavy objects, moderate sport, sex etc, I have had every blood test done , CT scan, echo, and doctors still don't know what seems to be the problem, does anyone have an idea what this could be?

These symptoms sound similar to my psvt tachycardia. I would get dizzy, nauseated, my vision would black out on me and my knees would give out but I would still be conscious of everything around me. My heart rate would randomly spike up then go back to normal usually after a long walk, a bit more strenuous day at work ect. I found that sipping on ice water helped bring me back around usually as well as resting. To get a diagnosis I of course got the halter monitor for a week and got lucky. Has a couple attacks while I was wearing it. I would talk to your cardiologist and see if your symptoms match up to psvt.

Good luck and I hope they figure out what's going on I know how scary an undiagnosed heart problem can be.
Morgan