My sister had an episode in the summer which took her to the hospital. She had heart palpitations and felt nauseous. They kept her overnight and did bloodwork which came back positive for cardiac arrest but then negative the second time she took it. It's a time sensitive thing though so perhaps the second one was taken after 24 hours. In any case she was to go to a cardiologist but never did. Lately she's been having heart palpiations all the time. The weird thing is it also makes her cough, kind of like she has to catch her breath. It can get worse when she is lying down. I'm trying to get her to go to the doctor but she procrastinates. Please does anyone know what this could be?