Spent some time in ER and overnight in hospital over the weekend. Doctors seem perplexed and I have follow ups with cardiologists this week. Symptoms are near passing out episodes due to heart palpitations when, and only when sitting upright. Standing, laying down, or reclining will stop the episode very quickly. I've had multiple tests, CT scans, etc and all have come out clean. I nearly passed out while driving before going to the ER. I recently came off of Xarelto which I took for 9 months due to a blood clot in my lungs last winter. Otherwise I've been healthy.