Sudden Cardiac Arrest occurs when the heart's normal electrical impulses are interrupted, causing the heart to suddenly start beating in an irregular rhythm, typically either ventricular fibrillation or pulseless ventricular tachycardia.
With the heart muscle fibrillating or quivering, the heart begins twitching uncontrollably rather than beating regularly. Consequently, the heart becomes incapable of delivering oxygen to the brain. Without oxygen, severe brain damage occurs and victims of cardiac arrest will die within minutes.
Sudden Cardiac Arrest is fatal but reversible, with the best chance of survival being a shock from a defibrillator within the first five minutes after collapse. In addition, CPR (Cardio-Pulmonary Resuscitation) is critical in order to sustain life and help to extend survival times however rapid defibrillation is the key to survival and the only definitive treatment for SCA.
How Does External Defibrillation Work?
One of the first records of a successful defibrillation was by physician Dr Claude Beck in 1947, who had constructed a rudimentary defibrillator using tablespoons and wooden handles. Dr Claude Becks device needed to be applied directly to the patients heart, exposing the patients chest. It wasn't until the 1950s when Dr Paul Zoll presented to the meeting of the American College of Surgeons and described a case of successful defibrillation of a patient through their chest rather than directly on their heart. Over the following decades Dr Paul Zoll explored the concepts of cardiac pacing and defibrillation and was awarded the Lasker Award in 1973 for his contribution to medical science.
Modern day defibrillators use Dr Zolls concepts and are designed as a public access device. These devices are designed to be portable, easily accessible and easy to use even for the untrained bystander.
Defibrillation reverses the cardiac arrest by sending an electrical current through the heart muscle cells, momentarily stopping the abnormal electrical energy and allowing the normal heart beat to resume. If the heart can be shocked quickly with a defibrillator within minutes after collapse, a normal heart rhythm may be restored and many victims can and do survive.
The Importance of Early Defibrillation
Critically, survival from a cardiac arrest relies upon a timely response from first responders i.e. bystanders. Greater than 50-70% of Sudden Cardiac Arrest victims survive if defibrillation occurs within the first 5 minutes. For every minute that passes, there is a 10% less chance of survival.
Stages of a Successful Sudden Cardiac Arrest
During the defibrillation process of a patient suffering from Sudden Cardiac Arrest the patient
- The patient’s heart goes from normal sinus rhythm to ventricular fibrillation or ventricular tachycardia. The patient will collapse suddenly due to oxygen deprivation. During this period, it’s possible that the patient might appear to be breathing, but these are agonal respirations, and it’s not normal breathing.
- While in either ventricular fibrillation or ventricular tachycardia, the patient is clinically dead without an regular heartbeat but they are not yet biologically dead. Their heart still has electrical activity while its “fibrillating” or quivering. Whilst the heart is still active, it’s not enough to sustain life.
- When a patient receives a “shock” from an AED, the energy from the AED passes between the attached defibrillator pads and through the patient’s heart. The energy delivered through the patient’s heart causes their heart cells to depolarize, stopping the fibrillating and ineffective rhythm. This process is known as defibrillating the patients heart.
- After the heart has been defibrillated, the heart goes back into a normal sinus rhythm wherein it starts recirculating oxygen-rich blood throughout their body. Their skin color may return to normal and, in some cases, they will start breathing on their own.
According to the Productivity Commissions 2023 Report on Government Services only 50% of first responder assets reached their patients in less than 9 minutes. This response time varied in each state and is outside the critical first minutes in which the casualty's life can be easily saved.
If properly educated, the general public can become less reliant on emergency services response times and more confident in implementing an action plan that will help to save lives.
Benefits of Easily Accessible Defibrillators
- Saves Lives: The primary benefit of using a defibrillator is that it can save lives. Every minute that passes without treatment reduces the chances of survival by 7-10%. By delivering a shock to the heart in the smallest amount of time, a defibrillator can restore a normal rhythm and increase the chances of survival.
- Improved Survival Rates: Studies have shown that the use of defibrillators can improve survival rates in cases of cardiac arrest. The AHA estimates that early defibrillation, within the first 3-5 minutes after collapse, can increase survival rates by as much as 60%.
- Reduced Brain Damage: When a person suffers a cardiac arrest, their brain can be deprived of oxygen for a long time. The lack of oxygen caused by the irregular heart beat can lead to brain damage. The quick use of a defibrillator can restore a normal heart rhythm, pumping oxygenated blood around the patients body, reducing the risk of brain damage.
- Reduces the Need for Hospitalisation: Early defibrillation can also reduce the need for long term hospitalization, as it can prevent further damage to the heart and other organs. This can result in significant cost savings for individuals and healthcare providers.
- Improved Quality of Life: For those who survive sudden cardiac arrest, the correct use of a defibrillator can significantly improve their quality of life. It can prevent long-term complications such as heart failure, which can lead to a reduction in mobility and overall health.
- Increased Public Awareness: The increased availability and use of defibrillators has led to greater public awareness of the importance of prompt action in the event of a cardiac arrest. This increased awareness has led to more people being trained in CPR and improved survival rates overall.
These critical medical devices have the power to reverse sudden cardiac arrest and, in many cases, restore normal heart rhythm when administered to a patient promptly. Defibrillation is the pivotal link in the chain of survival when time is of the essence, each passing minute diminishes the chances of a successful resuscitation.
To harness the full potential of defibrillation, it is crucial to take a proactive approach. Whether you're an concerned individual, a community leader, or a workplace manager, it's important to familiarize yourself with the availability and accessibility of defibrillators in your vicinity.
Ultimately, our collective commitment to understanding and advocating for the importance of defibrillation can make a profound difference in the survival rates of sudden cardiac arrest victims. By taking the initiative to learn more and promote accessibility to defibrillators, society contributes to a safer and more prepared environment, where every precious life has a fighting chance.
"Shocktober", a month-long campaign is dedicated to raising awareness about the critical role of CPR and early defibrillation in sudden cardiac arrest events. This initiative is designed to underscore the importance of quick and effective responses when lives are on the line. As part of this awareness campaign, "Restart a Heart Day" on October 16th takes center stage, offering individuals and groups a valuable opportunity to acquire and practice life-saving CPR techniques. Join us in exploring the vital aspects of this campaign and the pivotal role it plays in equipping communities with the knowledge and skills needed to save lives in emergency situations.
While every defibrillator will deliver a shock to a patient, not all defibrillators are built the same. Defibrillators can vary from semi-automatic to automatic operating modes, suitable for adult and paediatric patients, different methods and levels of energy discharge and variations in protection from environmental elements. Learn more in our next article "Choosing the Right Defibrillator: A Comprehensive Guide" which outlines the differences across brands and devices.
Explore our full range of defibrillators here.
