Sudden Cardiac Arrest (SCA)


  • Sudden cardiac arrest is when the heart suddenly stops beating. The most common cause is a blockage of the blood flow to the heart, causing a heart attack. However, if there is no blockage, it isn’t a heart attack. A sudden cardiac arrest is most often caused by a heart rhythm abnormality called ventricular fibrillation. In young, healthy people, often the cause of a sudden cardiac arrest can not be determined. Some young people are diagnosed with Long QT syndrome or Hypertrophic Cardiomyopathy, or another inherited heart rhythm condition.
  • Each year in Canada, 1/35,000 has a sudden cardiac arrest and unfortunately, unless it occurs in a hospital, only about 10% survive. This is because CPR and defibrillation are usually needed to quickly ‘re-start’ the heart.

Treatment/Standard of Care

Sudden cardiac arrest in a child or young adult (less than 35), requires careful evaluation by a cardiac specialist. If there is a sudden cardiac death, an autopsy can be helpful to determine if there is a blockage or a heart muscle disease. Heart rhythm abnormalities do not leave a scar, however.

Most survivors of a sudden cardiac arrest are treated with an implantable defibrillator and medications.

Additional Resources

Please note: The Canadian SADS Foundation provides links to external websites for informational purposes only. While we regard these as reputable sources of information, please be aware that The Canadian SADS Foundation is not responsible for the accuracy, legality, or content of the external site or for that of subsequent links.

Hearts in Rhythm Organization (HiRO)

Hearts in Rhythm Organization has a guide for patients and caregivers about SCA.

Heart Rhythm Society

Patient page about ventricular fibrillation from the Heart Rhythm Society (US).

Cleveland Clinic

Patient page explaining the difference between a heart attack and a cardiac arrest from the Cleveland Clinic (US).