I am a 35 year old female. About 16 months ago I fainted for the first time while driving. I went to the ER and had lots of tests run. Nothing was found- normal EKG, EEG, ct of brain, holter monitor, stress test, echo, sugar level. Over the next 9 months I fainted 7 times. Six months went by and I was fine. Last week I fainted again. I've been seeing a cardiologist. I've done an EP study, 4 different tilt table tests, blood volume test. I have an implanted loop recorder. It recorded the last fainting episode. What I do know is that I have low blood pressure (I took it after I fainted: 67/38). I was usually in the 80s/50s. My bp drops for some unknown reason and then my heart skips several beats. Then I fainted. I was previously taking a beta blocker to stabilize my bp. I no longer take it. I am taking theophylline. It raises my bp and heart rate. I am normal weight, exercise 5-6 days week. I've done 2 half marathons and 1 whole marathon. This all started 3 weeks after my marathon. We've talked about putting in a pacemaker. I'm scared. I have 3 kids under 11 years old.