What are the risk factors of sudden cardiac arrest?

There are many factors that can increase a person’s risk of sudden cardiac arrest and sudden cardiac death. The two leading risk factors include:

  • Previous heart attack (75 percent of SCD cases are linked to a previous heart attack) -A person’s risk of SCD is higher during the first six months after a heart attack.
  • Coronary artery disease (80 percent of SCD cases are linked with this disease) -Risk factors for coronary artery disease include smoking, family history of cardiovascular disease, high cholesterol or an enlarged heart.

Other risk factors include:

  • Ejection fraction of less than 40 percent, combined with ventricular tachycardia (see information below about EF)
  • Prior episode of sudden cardiac arrest
  • Family history of sudden cardiac arrest or SCD
  • Personal or family history of certain abnormal heart rhythms, including long QT syndrome, Wolff-Parkinson-White syndrome, extremely low heart rates or heart block
  • Ventricular tachycardia or ventricular fibrillation after a heart attack
  • History of congenital heart defects or blood vessel abnormalities
  • History of syncope (fainting episodes of unknown cause)
  • Heart failure: a condition in which the heart’s pumping power is weaker than normal. Patients with heart failure are 6 to 9 times more likely than the general population to experience ventricular arrhythmias that can lead to sudden cardiac arrest.
  • Dilated cardiomyopathy (cause of SCD in about 10 percent of the cases): a decrease in the heart’s ability to pump blood due to an enlarged (dilated) and weakened left ventricle
  • Hypertrophic cardiomyopathy: a thickened heart muscle that especially affects the ventricles
  • Significant changes in blood levels of potassium and magnesium (from using diuretics, for example), even if there is not organic heart disease
  • Obesity
  • Diabetes
  • Recreational drug abuse
  • Taking drugs that are “pro-arrhythmic” may increase the risk for life-threatening arrhythmias

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