I have been dealing the the following list of symptoms for 3 years. I have been to 5 cardiologist and 2 electro cardiologist as well as a therapist- they have not been able to positively diagnosis me. Holter monitors for a full month twice..showing about 3-8 times a day of tachycardia lasting anywhere from a few seconds to 2 hours.I have already had an ablation attempted to be done. And been on 20 different beta blockers. I am currently taking 5mg of lexapro. Previously on cardizem but not now. I have had a table tilt test that was negative. I'll take .25 mg of zanax and magnesium and salt tablets when I have it around when the symptoms start. They are in sequential order: nausea, diareaha, heart rate at 110 - when I start noticing, tunnel vision, palpitations, wobbly legs, heavy head at 130 bpm, sometimes I black out, usually around 160,once my heart rate goes back down to about 95 I get muscle spasms in my whole body but mostly in my feet and legs, exhaustion, more nausea and upset tummy. I have found stress, alcohol, barometric pressure and the mornings are the worst for me. This process of symptoms can last between 1 hour to 12 hours. Please help!