National Sudden Cardiac Arrest  Awareness 

Sudden cardiac arrest (SCA) is a leading cause of death worldwide, taking over 300,000 lives in the United States each year[1]. Unlike a heart attack, SCA occurs when the heart suddenly and unexpectedly stops beating, cutting off blood flow to vital organs. 

This October, National Sudden Cardiac Arrest Awareness Month draws attention to this critical health issue. Learning to recognize warning signs, getting screened, and knowing CPR can save lives. Let’s expand our understanding of sudden cardiac arrest and how to be proactive. 

What is Sudden Cardiac Arrest? 

Sudden cardiac arrest (SCA) refers to an abrupt loss of heart function that results in a lack of blood flow to the brain and other vital organs. It’s caused by an electrical malfunction that disrupts the heart’s normal pumping rhythm, often into rapid, chaotic quivering known as ventricular fibrillation. 

Without immediate treatment, SCA leads to death within minutes. Quick action is crucial. Approximately 95 percent of people who experience out-of-hospital SCA will die before reaching the hospital[2]. Rapid defibrillation using an automated external defibrillator (AED) offers the best chance of survival. 

While often confused with heart attacks, SCA differs in important ways: 

• Heart attacks occur when blood flow to part of the heart muscle is blocked. SCA is an electrical issue stopping heart rhythms. 
• Warning signs for heart attacks may occur hours or days before. SCA happens unexpectedly with little to no warning. 
• Heart attacks do not always lead to SCA. But SCA is a frequent and deadly consequence of heart attacks. 

Anyone can experience SCA, though certain individuals are at higher risk. Some causes include underlying heart conditions, structural abnormalities, electrophysiology issues, and channelopathies. 

Statistics on Sudden Cardiac Arrest

• Each year, around 356,000 people in the U.S. experience EMS-assessed out-of-hospital SCA[3]. This does not include SCA occurring in hospitals. 
• Only about 10% of people who experience out-of-hospital SCA survive[4]. Chances of survival are 2-3 times higher if a bystander administers CPR and uses an AED before EMS arrival. 
• SCA claims the lives of approximately 367,922 individuals in the U.S. annually. That’s more than 1,000 deaths per day[5]. 
• SCA is a leading cause of death in adults over 40. The risk increases significantly with age. 
• Men are at 2-3 times higher risk of SCA than women overall. However, women aged 45-54 see higher rates than men of the same age[6]. 
• African Americans face a higher incidence of SCA at younger ages compared to other groups[7]. 
• SCA costs around $33 billion annually in direct healthcare expenses and lost productivity[8]. Improved awareness and proactive steps can help reduce this toll. 

Causes and Contributing Factors 

Many cases of sudden cardiac arrest stem from pre-existing heart conditions. However, there are also other medical, genetic, and situational factors that may contribute. Main causes include: 

Coronary Heart Disease 

• Heart attacks – Blockages in coronary arteries can cut off oxygen to parts of the heart, causing damage that disrupts electrical rhythms and leads to SCA. 
• Ischemia – Reduced blood flow to the heart due to coronary artery disease. Even without full blockage, decreased oxygen can trigger dangerous rhythms. 

Structural Heart Abnormalities 

• Enlarged heart/cardiomyopathy – Weakened heart muscle impedes normal electrical signaling. 
• Congenital heart defects – Abnormal heart structures present from birth can predispose some to SCA. 

Inherited Arrhythmia Syndromes 

• Conditions like long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia (CPVT) carry genetic mutations affecting the heart’s electrical system that raise SCA risk, even in young, otherwise healthy people. 

Other Contributing Factors

• Recreational drugs – Cocaine, amphetamines, and certain supplements can impact electrical rhythms. 
• Electrolyte disturbances – Imbalances of minerals like potassium can disrupt signaling. 
• Trauma – Physical trauma is like a blow to the chest. Electric shocks or lightning strikes. 

Warning Signs and Symptoms 

Sudden cardiac arrest frequently occurs with no warning signs. However, some people may experience subtle symptoms in the days or weeks beforehand that indicate an increased risk. Symptoms to watch for include: 

• Racing, fluttering heartbeat (palpitations) 
• Dizziness or lightheadedness 
• Fainting (syncope) 
• Chest pain or shortness of breath 
• Fatigue despite adequate rest 

If these symptoms are new or worsening, it’s important to see a doctor for evaluation. They can help determine if you have any underlying heart issues requiring treatment. Catching problems early provides the best chance of preventing sudden cardiac arrest. 

Of course, it’s important to remember that most people with these symptoms will not have SCA. Many less serious conditions like anxiety, anemia, or dehydration can cause similar warning signs. Still, it’s wise to get checked out when these symptoms arise persistently. 

Risk Factors 

Several factors place a person in increased danger of experiencing sudden cardiac arrest:

Heart Disease 

• Prior heart attack 
• Coronary artery disease 
• Cardiomyopathy – Enlarged heart muscle 
• Heart failure 

Structural Heart Abnormalities 

• Congenital heart defects – Present from birth 
• Valvular disease – Leaky or stiff heart valves 

Inherited Syndromes/Conditions 

• Long QT syndrome – Causes dangerous arrhythmias
• Brugada syndrome – Abnormal electrical signals 
• Catecholaminergic polymorphic ventricular tachycardia (CPVT) – Inherited arrhythmia 
• Aortic aneurysm – Bulge in the aorta that can rupture 

Medical History 

• Previous cardiac arrest 
• Family history of sudden cardiac death – Especially immediate family members ● Diabetes mellitus 
• Chronic kidney disease 

Screening for Risk 

Some screening and diagnostic tests can check for underlying heart issues or abnormalities linked to sudden cardiac arrest. These include: 

• Electrocardiogram (EKG) – Records electrical signals in the heart 
• Echocardiogram – Uses ultrasound to image the heart’s structure 
• Cardiac MRI – Detailed imaging of heart muscle and function 
• Exercise stress testing – Monitors heart rhythm and blood pressure during exertion 
• Coronary angiography – Checks arteries for blockages 
• Electrophysiology (EP) study – Evaluates electrical signaling patterns 
• Genetic testing – Screens for mutations of inherited conditions 

Doctors may recommend screening for people with heart disease, risk factors, or a family history of SCA. Baseline EKGs are often part of routine sports physicals for student-athletes. 

The ultimate goal is to try to prevent SCA by identifying risks early. People with recognized heart conditions can undergo treatment and be monitored more closely. 

Treatment and Prevention of SCA 

Several evidence-based treatments help prevent or reduce sudden cardiac arrest risk among higher-risk individuals: 

• Implantable cardioverter defibrillator (ICD) – Small devices planted under the skin that detect and respond to dangerous heart rhythms with electrical pulses. 
• Anti-arrhythmic medications – Help stabilize abnormal rhythms. Common examples include amiodarone, sotalol, and mexiletine. 
• Pacemakers – Can override slow rhythms with electrical pacing and prevent disruption of normal rhythms. 
• Ablation procedures – Use catheters to manipulate faulty electrical pathways causing arrhythmias.
• Coronary revascularization – Opening of blocked arteries via angioplasty or stents improves blood flow to the heart. 
• Avoiding triggers – Limiting stimulants, electrolyte imbalance, and trauma risk for those prone to SCA. 

For individuals facing the highest risk, an implantable defibrillator reduces the risk of death when compared to using medications alone[9]. Unfortunately, not everyone receives the recommended preventive treatments prior to SCA. Increased awareness and proactive screening help identify those who may benefit. 

Emergency Response – ABCs of SCA 

Prompt action is critical when someone experiences a sudden cardiac arrest. Follow these ABCs for the best chance of survival: 

A – Call 9-1-1 

• Call for emergency medical help immediately. EMS teams are equipped with defibrillators and resuscitation equipment not available to the general public. 

B – Start CPR 

• Begin chest compressions to manually pump blood through the body since the heart has stopped. Press hard and fast in the center of the chest. 

C – Get an AED 

• Use an automated external defibrillator (AED) as soon as possible to analyze heart rhythms and deliver an electric shock to restore normal rhythms when appropriate. Even untrained bystanders can use AEDs. 
• Try to resume chest compressions immediately after the shock. Continue CPR until EMS arrives. 

Starting CPR quickly and using an AED within 3-5 minutes optimizes survival chances[10]. Brain death starts around 4-6 minutes without blood flow. Rapid defibrillation is vital. 

Many public places like schools, offices, gyms, and airports now have AEDs installed. However, increased access and more people trained on both CPR and AEDs would save even more lives. 

The American Heart Association (AHA) recommends performing CPR chest compressions at a rate of 100 to 120 beats per minute.

Cardiac Rehabilitation and Living with ICDs 

For those revived from cardiac arrest, additional treatment focuses on recovery and prevention of recurrence:

• Targeted medications and lifestyle changes to improve heart health are imperative after any heart event. Follow the doctor’s guidance for medicine, diet, exercise, and smoking cessation. 
• Cardiac rehabilitation programs help people safely regain strength and stamina. They provide structured, monitored exercise, education, and counseling. 
• People getting an implantable cardioverter defibrillator (ICD) require some adjustment to living with the device. Expect some reasonable lifestyle modifications like avoiding full contact sports to prevent trauma to the ICD. But most daily activities can be resumed. Always carry your ICD ID card noting its presence. 
• Emotional health support assists with any anxiety, depression, or trauma related to a cardiac arrest. Discuss any struggles with your treatment providers. Consider joining a support group. 

Raising Awareness to Stop Sudden Cardiac Arrest 

Despite being a major public health threat, sudden cardiac arrest remains poorly understood by many. Increased public awareness and education on SCA is vital for saving lives. Here’s how you can help during National SCA Awareness Month: 

Learn the Warning Signs 

Know the common symptoms signaling increased risk. Don’t dismiss new or worsening signs like palpitations, fainting, or shortness of breath. Get checked out. Early detection of heart problems yields more options for prevention. 

Ask About Screening 

Talk to your doctor about whether you should get a baseline EKG or other heart screening based on your age, family history, or health status. Check if your child’s school requires cardiac screening for student-athletes. Catch issues early. 

Take a CPR/AED Class 

Prepare yourself to act in an emergency by taking CPR and defibrillator training courses. Local hospitals, fire departments, and the Red Cross often offer classes. Refresh skills annually. You could help save a life. 

Advocate for AED Access 

Support campaigns to place automated external defibrillators (AEDs) in public spaces. Encourage schools, workplaces, transit centers, and community hubs to make this basic lifesaving equipment available on-site.

Even small efforts raise critical awareness surrounding sudden cardiac arrest. Together we have the power to push for policy changes that make SCA emergency response training and technology more accessible. Plan ahead to prevent more untimely deaths. 

References

[1] Benjamin, Emelia J et al. “Heart Disease and Stroke Statistics-2019 Update: A Report From the American Heart Association.” Circulation vol. 139,10 (2019): e56-e528. doi:10.1161/CIR.0000000000000659 

[2] Evans, T. “Cardiac arrests outside hospital.” BMJ (Clinical research ed.) vol. 316,7137 (1998): 1031-2. doi:10.1136/bmj.316.7137.1031 

[3] Yadav, Priya. “Attending Training Workshop of BLS/ACLS.” JNMA; journal of the Nepal Medical Association vol. 60,254 916-917. 1 Oct. 2022, doi:10.31729/jnma.7782 

[4] Sudden Cardiac Arrest Foundation. ‘Latest Statistics: 1,000 People Suffer Sudden Cardiac Arrest Each Day in U.S.; Only 10% Survive.’ 
https://www.sca-aware.org/sca-news/latest-statistics-1000-people-suffer-sudden-cardiac-arrest each-day-in-us-only-10-survive. Published Date: January 29, 2020. 

[5] Sudden Cardiac Arrest Foundation. ‘Latest Statistics: 1,000 People Suffer Sudden Cardiac Arrest Each Day in U.S.; Only 10% Survive.’ 
https://www.sca-aware.org/sca-news/latest-statistics-1000-people-suffer-sudden-cardiac-arrest each-day-in-us-only-10-survive. Published Date: January 29, 2020. 

[6] Winkel, B.G., Risgaard, B., Bjune, T., et al. “Gender Differences in Sudden Cardiac Death in the Young – A Nationwide Study.” BMC Cardiovascular Disorders, vol. 17, no. 1, 2017, p. 19,
https://doi.org/10.1186/s12872-016-0446-5. 

[7] Fender, Erin A et al. “Racial differences in sudden cardiac death.” Journal of electrocardiology vol. 47,6 (2014): 815-8. doi:10.1016/j.jelectrocard.2014.07.023 

[8] Committee on the Treatment of Cardiac Arrest: Current Status and Future Directions; Board on Health Sciences Policy; Institute of Medicine; Graham R, McCoy MA, Schultz AM, editors. Strategies to Improve Cardiac Arrest Survival: A Time to Act. Washington (DC): National Academies Press (US); 2015 Sep 29. 2, Understanding the Public Health Burden of Cardiac Arrest: The Need for National Surveillance. 

[9] Exner, Derek V., Klein, George J., Prystowsky, Eric N. “Primary Prevention of Sudden Death With Implantable Defibrillator Therapy in Patients With Cardiac Disease: Can We Afford to Do It? (Can We Afford Not To?).” Circulation, vol. 104, no. 12, 2001, pp. 1564-1570, https://www.ahajournals.org/doi/full/10.1161/hc3801.096395.

[10] Ibrahim, Wanis H. “Recent advances and controversies in adult cardiopulmonary resuscitation.” Postgraduate medical journal vol. 83,984 (2007): 649-54. doi:10.1136/pgmj.2007.057133