Tachycardia (fast heartbeat)
Sudden cardiac arrest (SCA)
- Over 33,000 people experience an out of hospital cardiac arrest in Australia every year. Less than 9% will survive.1
- Implantable cardioverter defibrillators (ICDs) maybe ~96% effective in treating ventricular arrhythmias.2–5
SCA is an electrical problem with the heart that causes a dangerously fast heart rhythm (ventricular fibrillation). The rapid, irregular heart rhythm causes the heart to quiver rather than pump. When the heart stops pumping blood, oxygen cannot reach the body and brain. If not treated immediately, SCA is usually fatal.
Globally, cardiac arrest claims more lives than colorectal cancer, breast cancer, prostate cancer, influenza, pneumonia, auto accidents, HIV, firearms, and house fires combined.1
1. SCA is an electrical issue.
SCA is a rhythm problem that prevents the heart from pumping blood to the brain and organs.
2. A heart attack is a plumbing issue.
A heart attack is typically caused by a blockage in a blood vessel to the heart muscle. This can permanently damage part of the heart and can lead to SCA.
A number you should know.
EF is the percentage of blood that is pumped out of the heart with each heartbeat. Your doctor knows how well your heart is pumping based on your EF number. It is important for you and your doctor to check your EF regularly.
People with
a low EF are at
an increased
risk of SCA.6
Typical EF ranges7:
55–70%
Heart’s pumping ability is NORMAL
40–55%
Heart’s pumping ability is
BELOW NORMAL
40% or below
Heart’s pumping ability is
LOW
AED
An automated external defibrillator, or AED, is a portable device that measures the heart’s electrical activity. It is used by emergency response teams or the general public to shock the heart.
ICD
An ICD system has two parts: the defibrillator and the leads.
- A defibrillator continuously monitors the heart and automatically corrects heart rhythms.
- Leads are thin, soft, insulated wires about the size of a spaghetti noodle. They carry the electrical impulse from the ICD to your heart. They also send information about the heart’s natural activity back to the ICD.
Information on this site should not be used as a substitute for talking with your doctor. Always talk with your doctor about diagnosis and treatment information.
References
1
Cardiac Arrest and Automated External Defibrillators. NSW Health. Available at: https://www.health.nsw.gov.au/cardiacarrest/Factsheets/cardiac-arrest-organisations.pdf. Accessed 21st February, 2024.
2
Lambiase PD, Theuns DA, Murgatroyd P, et al. Subcutaneous implantable cardioverter-defibrillators: Long-term results of the EFFORTLESS study. Eur Heart J. 2022;43(21):2037–2050.
3
Larsen JM, Heath FP, Riahi S, et al. Single and dual coil shock efficacy and predictors of shock failure in patients with modern implantable cardioverter defibrillators-a single-center paired randomized study. J Interv Card Electrophysiol. 2019;54(1):65–72.
4
Knops RE, van der Stuijt W, Delnoy PPHM, et al. Efficacy and safety of appropriate shocks and antitachycardia pacing in transvenous and subcutaneous implantable defibrillators: Analysis of all appropriate therapy in the PRAETORIAN trial. Circulation. 2022;145(5):321–329.
5
Bänsch D, Bonnemeier H, Brandt J, et al. Shock efficacy of single and dual coil electrodes–new insights from the NORDIC ICD Trial. Europace. 2018;20(6):971–978.
6
Epstein AE, DiMarco JP, Ellenbogen KA, et al. ACC/AHA/ HRS 2008 Guidelines for device-based therapy of cardiac rhythm abnormalities [corrections appear at J Am Coll Cardiol. April 21, 2009; 53(16):1473. J Am Coll Cardiol. January 6, 2009;53(1):147]. J Am Coll Cardiol. 2008;51(21):e1–62.
7
Ejection Fraction: What the Numbers Mean. Penn Medicine. Available at: https://www.pennmedicine.org/updates/blogs/heart-and-vascular-blog/2022/april/ejection-fraction-what-the-numbers-mean#:~:text=In%20most%20cases%2C%20ejection%20fraction,pumped%20out%20during%20each%20beat. Accessed October 9, 2023.