Is anyone experiencing syncopal( fainting) episodes?

I have Myasthenia Gravis, I'm 10 months post Thymectomy, currently on IVIG 2 days every other week waiting on a clinical trial to hopefully get these symptoms under control or even remission! 🙏🏼 But, I started passing out a couple of months ago. Has anyone else experienced fainting spells?? Please offer any ideas! I'm starting with cardiology testing but, we really don't think it's my heart...