What is the Difference Between Heart Attack and Cardiac Arrest?

Heart attacks and cardiac arrests are serious but distinct medical conditions. Simply put, cardiac arrest is related to the heart's electrical activity, while a heart attack is related to blood flow. Let's explore the main differences between these two medical emergencies.

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What Is a Heart Attack?

A heart attack, or myocardial infarction (MI), occurs when a coronary artery, which supplies blood to the heart, fails to provide an adequate blood supply to the heart muscle. This often happens due to a clot that suddenly forms in a narrowed artery, blocking the blood flow. In other cases, a heart attack can be caused by the progressive narrowing of arteries due to the buildup of cholesterol plaques.

When blood flow is reduced or blocked, the heart muscle cells do not receive enough oxygen and begin to die. This damage to the heart muscle can lead to heart failure and, in severe cases, death. Recognizing the signs of a heart attack quickly is crucial, as intervening within 90 minutes of the onset of symptoms can limit damage to the heart and save lives.

Symptoms of a Heart Attack

The most common symptom of a heart attack is persistent chest pain or a feeling of pressure. However, this symptom can be less evident in women, who might experience other signs. Additional symptoms include:

• Shortness of breath.
• Nausea.
• Vomiting.
• Sudden, profuse sweating.
• Dizziness.
• Extreme weakness.
• Anxiety.

A heart attack is a potentially fatal medical emergency. If you or someone near you experiences these symptoms, it is essential to call 112 immediately. Emergency medical services can provide the quickest and safest route to the hospital and are trained to treat the patient during transport.

What Is Cardiac Arrest?

Cardiac arrest occurs when the heart stops beating, typically due to a malfunction in the electrical system that controls the heart's rhythm. Normally, the heart beats due to regular electrical impulses from its electrical system; for example, one electrical impulse per second corresponds to a heart rate of 60 beats per minute. However, if the heart's electrical system fails, the result can be cardiac arrest.

One of the most common forms of cardiac arrest is ventricular fibrillation (VF), the leading cause of sudden cardiac death. This condition can affect even apparently healthy individuals without any known heart disease. In adults, ventricular fibrillation is the most frequent arrhythmia at the time of cardiac arrest. It is an extremely rapid and disorganized arrhythmia where the heart's electrical system goes into chaos, disrupting circulation to the body and brain. If not treated immediately, this condition leads to death within minutes.

Another type of cardiac arrest is ventricular tachycardia (VT). In this condition, the heart's electrical system malfunctions but in a less chaotic manner than ventricular fibrillation (VF). In VT, the heart rate accelerates significantly and originates from the ventricles. This increase in heart rate causes the heart muscle to become inefficient, compromising the heart's ability to pump blood effectively.

Another possible alteration in heart rhythm is bradycardia. Unlike tachycardia, the heart beats too slowly in bradycardia. This slowing of the heartbeat fails to maintain sufficient blood pressure, compromising blood circulation.

In summary:

• Tachycardia: The heart rate is faster than normal.
• Bradycardia: The heart rate is slower than normal.
• Fibrillation: The heart rate is irregular and disorganized.

In addition to arrhythmias, cardiac arrest can also be caused by other serious medical conditions, including:

• Heart attack.
• Heart failure.
• Cardiac tamponade (severe chest trauma, such as that caused by an accident).
• Severe myocarditis.
• Respiratory failure.
• Genetic conditions, such as Brugada syndrome, which can cause sudden death due to cardiac arrest.

What links all these conditions is that a heart attack can lead to cardiac arrest, especially if the blocked artery supplies part of the heart's electrical system. The lack of blood in that area can cause the electrical system to malfunction or stop, thereby stopping the heart's beat.

A heart attack can also cause such extensive damage to the heart muscle that it can no longer function properly, causing the heart to stop beating. Additionally, a previous heart attack can indirectly predispose to cardiac arrest. This is because the heart attack leaves a scar in the affected heart tissue, which can interfere with the heart's normal electrical impulses, leading to dangerous rhythms such as ventricular fibrillation (VF) or ventricular tachycardia (VT).

Symptoms of Cardiac Arrest

The symptoms of cardiac arrest can appear suddenly and dramatically. Common signs include:

• Sudden loss of consciousness.
• Absence of pulse.

Before cardiac arrest occurs, symptoms related to the underlying cause may emerge, such as:

• Chest pain if the arrest is caused by a heart attack.
• Palpitations if it is due to an arrhythmia.
• Difficulty breathing if the cause is respiratory failure.

Cardiac arrest is an extremely serious medical emergency that can be fatal if not treated immediately. In the presence of these symptoms, it is essential to call 112 right away, describe the observed signs in detail, and start cardiopulmonary resuscitation (CPR) immediately, following the instructions provided by the emergency dispatch staff. If available, the use of an AED (Automated External Defibrillator) should occur as quickly as possible to restore a normal heart rhythm.