A couple of months ago I had a bad anaphylaxis reaction to Penecillin and nearly died, since then I am plagued with palpatations. I have had a few ECG's and blood tests and nothing is showing up. I am currently waiting for an appointment to have a 24hr heart monitor and to see a cardiologist. Anyone have any info on what could be causing this as when they are bad I feel tired and shaky. Thank you