I have experienced twice. And from then on, I haven't experienced any attacks yet. When the attack was gonna happen, I felt a little stress at first, the stress began to increase, then it got more tense, then boom I had it. I thought I was like really dead. I was ventilating, sweating, thrembling and overthinking at the same time. But after moments later I was normal. By the way my attack was caused by fear, I used to fear devil too much.