Sudden cardiac arrest tends to happen without warning. Usually, the first sign is someone fainting, collapsing or seeming to be lifeless. You may not be able to feel a pulse. It’s critical to call 911 right away.
Recent studies of SCA survivors find that, in some cases, people remember that something didn’t feel quite right beforehand. They recalled:
Another study shows that half of patients ages 35 to 65 had warning signs — mainly chest pain and shortness of breath in the 24 hours before the SCA. Some had warning signs for weeks.