My mother has always had arrhythmia. She thought it must have been normal. She would usually cough and it would stop. She now suffers from AF(artrial fibrillation) or at least that's the latest diagnosis. She has had 3 episodes when her heart rate would go up to over 200 bpm. What's so strange is the fact that this always happens in the Spring (April or May). The episodes have occurred almost a year apart (each Spring) for the past three years. I would like to know if her natural histamine, a chemical produced by the immune (disease-fighting) system of the body, could have something to do with this happening each Spring.