Sudden Cardiac Arrest For Tachycardia

What is Sudden Cardiac Arrest?

Over 33,000 people experience an out of hospital cardiac arrest in Australia every year. Less than 9% will survive.

SCA is a condition in which the heart suddenly and unexpectedly stops beating. If this happens, blood stops flowing to the brain and other vital organs. SCA can cause death if it’s not treated within minutes. 2

SCA vs. Heart Attack

Sudden cardiac arrest is not the same as a heart attack. A heart attack is a “plumbing” problem, caused by blockage(s) in the arteries leading to the heart and killing heart muscle. A heart attack may lead to a sudden cardiac arrest event.

What are the risk factors for SCA?

  • Previous heart attack or SCA
  • Family history of SCA or other heart disease
  • Heart failure
  • Low ejection fraction
  • Rapid or abnormal heartbeats starting in the bottom chambers of the heart

What are the symptoms of SCA?

  • Dizziness
  • Racing heartbeat
  • Loss of consciousness

Treating SCA Through Defibrillation

A way to treat SCA is through defibrillation.1 It involves delivering electrical shock to the heart to restore the normal heartbeat. There are two types of devices that can deliver these electrical shocks: AEDs and ICDs.

Automated External Defibrillator (AED)

An AED is a portable device used by emergency response teams or the general public to shock the heart.

Implantable Defibrillator (ICD)

An ICD is a device implanted underneath the skin, usually near the collarbone. One or more wires, called leads, run from the ICD through the veins and into the heart. It continuously monitors the heart rate. If it detects an abnormal or fast heart rate, low or high energy shocks are sent to the heart to correct the heart rate.


Zipes DP, Roberts D, for the Pacemaker-Cardioverter-Defibrillator investigators. Results of the International Study of the Implantable Pacemaker Cardioverter-Defibrillator: A Comparison of Epicardial and Endocardial Lead Systems. Circulation. July 1, 1995;92(1):59-65.