It can be caused by a lot of medications. Some Antiarrythmics can cause it. I had to have an ablation because the antiarrythmics caused me to have it when I took them for AFib. You might need the predisposition to get it from the medications but if you have it the list of medications you have to stay away from is quite daunting. That is one of the reasons they keep you in the hospital when you start antiarrythmics, to make sure you don't have that issue.