I am new at this so hope this thread is not lost in the multitudes. I have done a bit of searching on the internet but find it very frustrating. I have experienced episodes but cannot tie them down to any specific trigger. They hae happened a bit more frequently of late. Usually when I am playing tennis. My heart suddenly start racing so fast I am short of breath. It is an effort even to talk. It sometimes takes only 3-5 minutes and then does slow down slowly but goes straight back to normal. If I can sit down straight away and just wait it out then I am fine and can carry on playing without an occurrence. Sometimes it takes up to 20 minuste however and is very embarrassing. I wait till I am not lightheaded and breathing ok but my heart is still racing and although I feel fine while doing nothing, just two quick steps or movements has me breathing like I have run a marathon and I get dizzy. I played in a tournament yesterday and took five minutes on the side but I could see it was going to be a long episode so went back on court hoping to put in minimum effort as we had two games only to win the match. After three points with minimum effort I was wanting to vomit and then found I could hardly breathe and was straining and making loud wheezing noices like people with asthma! I was trying not to panic and trying to concentrate just on breathing cause I thought at that moment if it did not come right I was going to DIE. Have had a big fright. What can I do when this sort of thing happens?