That's how my first happened, almost exactly the same, out of the blue and thought I was dying. I was at home getting ready to pick my then 8 year old up from school, doing my make up in the loo, I fell to my knees and had to crawl to the phone to call my mum who went and got my daughter (my only thought was of her standing alone at school, which was adding to the panic). I thought I was dying too. After that I'd get them up to 10 times per day. Took some major psychotherapy and beta blockers to sort out. I was going through years of severe stress and my brain just couldn't take it any longer. Im so glad your husband has not experienced them too many times after that, they're the most horrid thing and until someone has one, or is there with someone having one, it's hard to understand just how severe they can be.