I had heart palpitations at one point and DHEA was among the suspects, however there was no clear conclusion on what was the cause. At that time I must have been on DHEA for probably more than a year without any problem; earlier I'd taken it for another maybe 6 months - and hadn't had any issues then either. Also at the time of the palpitations my TSH had shot up a lot, which should not be related to the DHEA but might be related to the heart palpitations. Also in the process I found family history of heart palpitations that I wasn't aware of, so it could just have been a coincidence that it came up then.
I'm betting on it having been a coincidence and have restarted DHEA recently (no issues so far), but who knows. How much of it are you taking? Uh, it's sad to have to face such uncertainties and tradeoffs.