I sometimes get what they call PAT's. I forget exactly that that stands for. Pulmonary Arterial Tachardia or something like that. My heart will start racing around 220/minute. Blood pressure drops, no fun at all. Usually last less than a minute, but have gone on as long as 2 hours. When they go on awhile, my veins start to hurt throughout my body. The doctors aren't worried about it though. Kinda of a 'Oh, it's only a PAT, it's nothing to worry about'. But I also have an prolapsed tricuspid valve.....so I worry about it. heh.
Did have an odd sensation a few days ago, and my heart was up about 120/minute. Had me hyperventilating. I wondered if it was related to the seizures. It was another hour till I needed to take my meds, so I went ahead and took them early. And that seemed to solve the problem.