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:
- Dizziness
- Unexplained shortness of breath
- Chest pains
- Seizures (usually in the arms and legs)
- Feeling sick to the stomach or vomiting an hour before the event
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.
What Increases Your Risk?
Why sudden cardiac arrest happens is not clearly understood. It is most often caused by a dangerous heart rhythm called ventricular fibrillation.
SCA can happen to anyone at any age. But the risk is greater among certain people. For example, it is more likely if you’ve had an SCA. And it’s more likely if a parent, child or sibling has had one. Men and African Americans also are at greater risk.
Still, certain diseases or conditions can cause the heart’s electrical system to misfire and lead to SCA. These include:
• Coronary heart disease
• Structural changes in the heart, for example, a thickened heart muscle/enlarged heart
• Heart failure with reduced pumping function, often referred to as a low ejection fraction (ejection fraction less than 35%)
• Heart attack – 75% of people who suffer sudden cardiac arrest were found to have had a heart attack, many of which went undiagnosed; survivors of heart attack are 4 to 6 times more likely to have SCA than the general population
• Physical stress such as trauma, blood loss, dehydration/electrolyte imbalance or (in rare cases) very intense physical activity
• Heart problems you are born with make you more prone to heart rhythm problems.