Cardiac Arrest vs Heart Attack: Guide to Understanding Causes And Symptoms

Introduction 

Cardiovascular diseases cause the majority of deaths worldwide. These are heart and blood vessel disorders that include heart attack, cardiac arrest, heart failure, etc. While these terms are frequently heard and used, each represents a distinct heart-related crisis with different causes and treatments. Understanding the differences between Cardiac Arrest vs Heart Attack is vital, as each requires distinct interventions to manage or treat.

Cardiac Arrest and Heart Attack - Difference 

Cardiac arrest and heart attack are both critical heart conditions, but they are often confused and used interchangeably by many. However, is heart attack and cardiac arrest the same? No, they differ in their causes, symptoms, and treatment approaches.

Cardiac arrest occurs when the heart suddenly stops beating due to an electrical malfunction, disrupting its ability to pump blood. This is often caused by an arrhythmia (abnormal heart rhythm), such as ventricular fibrillation.

Cardiac arrest symptoms include:

• Sudden collapse
• No pulse
• No breathing
• Loss of consciousness
• Immediate onset with no warning

Heart attack, also known as myocardial infarction, occurs when a clot in the coronary arteries blocks the blood flow to a part of the heart muscle. The blockage deprives the heart muscle of oxygen, causing damage or death to part of the heart tissue. 

Heart attacks used to be a worry for older people, but not anymore. Younger people are now experiencing heart attacks too. Cause of heart attack at young age include poor diet, and lifestyle-related disorders such as obesity, diabetes, high blood pressure, and elevated cholesterol levels.  

Heart attack symptoms can appear gradually or suddenly and include:

• Chest pain or discomfort 
• Pain in the stomach, jaw, neck, arms, back, etc.
• Shortness of breath
• Nausea
• Cold sweats, or light-headedness

Symptoms Before Cardiac Arrest

Symptoms before cardiac arrest can vary, and in some cases, there may be no warning signs at all. However, in many instances, people may experience symptoms hours, days, or even weeks before a cardiac arrest. Recognizing these early signs and symptoms can sometimes help prevent the worst outcome. Here are some common symptoms that may appear before cardiac arrest:

• Chest pain
• Shortness of breath or difficulty breathing
• Palpitations or irregular heartbeats usually indicate arrhythmias, which can lead to cardiac arrest if untreated
• Dizziness or light-headedness due to reduced blood flow to the brain caused by heart problems
• Fatigue or weakness
• Nausea or vomiting
• Profuse sweating (cold sweat) without physical activity
• Anxiety
• Syncope (fainting or collapse) due to a sudden drop in blood flow to the brain

Which is More Dangerous - Heart Attack or Cardiac Arrest

‍Although both are medical emergencies, cardiac arrest requires immediate attention as it can lead to death within minutes. In cardiac arrest, the heart stops suddenly, cutting off the blood flow to organs. Immediate administration of CPR (Cardiopulmonary Resuscitation) and defibrillation is critical within the first few minutes (the golden minutes) to restore the heart's rhythm and increase survival chances.

In contrast, during a heart attack (myocardial infarction), the symptoms often develop more gradually as blood flow to the heart muscle is reduced due to a blockage in the coronary arteries. 

The survival rate is significantly better with timely medical attention (medications or surgical intervention). The critical first hour (golden hour) following the onset of a heart attack is critical. During this period, prompt medical intervention is vital in reducing the extent of heart muscle damage and improving the chances of survival. However, untreated heart attacks can also lead to cardiac arrest.

Difference Between Heart Attack, Heart Failure, and Heart Block  

Heart attack (myocardial infarction) occurs due to a lack of blood flow to part of the heart muscle depriving oxygen, and causing damage or death to part of the heart tissue. Immediate medical intervention is crucial to minimize damage, and treatments often include medications to dissolve the clot, stent placement, or bypass surgery to restore blood flow. Heart Failure or congestive heart failure, refers to the heart’s inability to pump enough blood to meet the body's needs. Heart failure can be chronic (long-term) or acute (sudden). Causes: Conditions such as coronary artery disease, high blood pressure, heart valve disease, cardiomyopathy, or a previous heart attack can weaken the heart making it harder to pump blood. Symptoms may develop slowly may include:

• Dyspnea or shortness of breath
• Fatigue and weakness
• Edema in the ankles, feet, and legs
• Rapid or irregular heartbeat
• Wheezing
• Cough with white or pink mucus with blood spots
• Swelling in the abdomen
• Sudden weight gain from fluid buildup
• Nausea
• Lack of appetite
• Confusion, or difficulty concentrating
• Chest pain

Heart block, (atrioventricular block or a conduction disorder) occurs due to a disruption in the heart’s electrical system delaying the transmission of electrical signals and leading to irregular heartbeat. Heart block can be of varying degrees of:

• First-degree heart block: A mild form, often asymptomatic, and may not require treatment.
• Second-degree heart block: Delayed transmission of electrical signals causing skipped heartbeats.
• Third-degree (complete) heart block: Severe form, leading to a significant reduction in heart rate and potentially life-threatening symptoms.

Causes: Aging, heart disease, or medications can affect the heart's electrical impulses causing heart block. Symptoms of heart block may include:

• Chest pain
• Dizziness
• Fainting
• Heart palpitations
• Tiredness
• Shortness of breath
• Nausea
• Rapid breathing

Treatment varies based on the severity of the block and may include medications, lifestyle changes, or placement of a pacemaker to regulate the heart’s rhythm.

Reasons for Sudden Cardiac Arrest (SCA)

Sudden cardiac arrest occurs when the heart stops beating suddenly and unexpectedly. Immediate medical attention is critical for survival. Primary reasons for sudden cardiac arrest include:

• Arrhythmias (Abnormal Heart Rhythms): 
  • Ventricular Fibrillation (VF): Most common cause of SCA. In the heart, the lower chambers contract rapidly without pumping blood to the rest of the body. 
  • Bradyarrhythmias: Extremely slow heart rhythms (bradycardia).
• Coronary Artery Disease (CAD): 
  • Heart attack (myocardial infarction) caused by narrowing or blockage of coronary arteries due to atherosclerosis.
  • Silent Heart Attack: Heart attack without the typical symptoms.
• Cardiomyopathy (heart muscle disease).
• Congenital heart disease: Individuals born with structural heart abnormalities. 
• Severe electrolyte imbalances: (e.g., hyperkalemia or hypokalemia) can disrupt the heart’s electrical activity leading to cardiac arrest.
• Heart Failure: Weak heart muscles cannot pump blood effectively. 
• Structural heart problems such as scar tissue from previous heart surgery, or valvular heart disease (e.g. aortic stenosis) can increase the risk of SCA.
• Long QT syndrome and other inherited arrhythmias affect the heart’s electrical system and predispose individuals to dangerous arrhythmias.
• Drug use (cocaine, methamphetamines) or Alcohol consumption can trigger cardiomyopathy, arrhythmias, or coronary artery spasms.
• Severe physical stress in people with underlying heart disease can trigger arrhythmias and lead to SCA.

Reasons for Sudden Heart Attack in a Healthy Person

A sudden heart attack in a healthy person, though rare, can occur and is often unexpected. Sudden heart attack can be triggered due to:

• Undiagnosed heart issues such as undetected coronary artery disease or genetic predispositions.
• Severe physical stress like intense exercise. 
• Substance abuse such as stimulants or recreational drugs.
• Imbalances of electrolytes such as potassium can affect the heart’s function and trigger a heart attack.

Conclusion

Despite a healthy appearance, everyone must be aware of their heart health and manage risk factors proactively.

It is crucial for maintaining good heart health, as this can prevent various heart diseases, including heart attacks, cardiac arrest, and strokes. Prioritizing heart health through lifestyle changes such as a healthy diet, regular physical activity, avoiding smoking, and drugs, managing stress, maintaining a healthy weight, and regular medical check-ups can significantly reduce the risk of cardiovascular diseases.

FAQ’s

1. Can a person survive a cardiac arrest?

Yes, a person can survive a cardiac arrest if they receive immediate medical intervention including CPR (cardiopulmonary resuscitation), defibrillation, and emergency medical attention. Survival largely depends on how quickly these life-saving measures are provided. The faster you take these actions, the better the chances of survival. Many people who survive cardiac arrest also need further treatment to prevent future events.

2. Which is more serious, a heart attack or a cardiac arrest?

Both are serious medical emergencies, but cardiac arrest is generally more life-threatening. Cardiac arrest is more serious because it causes immediate death without intervention, while a heart attack is dangerous but may allow for more time to seek treatment. 

3. What is the main cause of cardiac arrest?

The main cause of cardiac arrest is an abnormal heart rhythm, also known as an arrhythmia, particularly ventricular fibrillation. The increasing prevalence of lifestyle-related diseases, such as coronary artery disease (often due to poor diet, smoking, high cholesterol, and high blood pressure), is a significant contributor to cardiac arrest cases.

4. Can a person be saved from cardiac arrest?

Yes, a person can be saved from a cardiac arrest depending on how quickly they receive immediate medical intervention including:  

• CPR (Cardiopulmonary Resuscitation) helps maintain blood flow to the brain and vital organs and can keep oxygen circulating even if the heart is not beating.
• Defibrillation delivers an electric shock to restore the heartbeat. Quick defibrillation is crucial, and survival rates drop significantly every minute without it.
• Emergency medical attention after CPR and defibrillation are needed to stabilize the person and address the underlying cause of the cardiac arrest.

5. Can a healthy person have a sudden cardiac arrest?

Yes, a seemingly healthy person can experience sudden cardiac arrest. While this is rare, factors such as undiagnosed heart conditions (genetic arrhythmias, hypertrophic cardiomyopathy, etc.), severe physical stress (intense exercise, extreme dehydration, or heat stroke), substance abuse, and electrical or electrolyte imbalances can trigger cardiac arrest. Regular check-ups and awareness of any family history of heart conditions can help identify potential risks. 

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About the Authors
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Dr. Satish Madiraju, a renowned cardiologist is passionate about consumer heart health and is on a mission to prevent a million heart attacks. He shares his expertise not only on heart health but also on leadership, digital health, and improving patient experience.

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Dr. Florence Suma is passionate about writing creative, clear and well-researched articles. With a Ph. D in Food Science & Nutrition, she provides reader-friendly articles that are reference-backed and adhere to the ethics of writing.