Sudden Cardiac Arrest (SCA) is a life-threatening condition where the heart suddenly stops beating effectively. This abrupt disruption in heart function prevents blood from circulating to vital organs like the brain, leading to rapid loss of consciousness and potential death within minutes if immediate treatment isn't provided.
Key Points:
- Prevalence: SCA is a significant public health concern, claiming over 350,000 lives annually in the United States and 36,000 in Canada. In the US, it's estimated that one person dies from SCA every 90 seconds, surpassing the death rates of breast cancer, AIDS, and lung cancer.
- Urgency of Treatment: Immediate treatment is crucial for survival. Unfortunately, due to the sudden and unexpected nature of SCA, timely access to medical intervention is often challenging. As a result, a staggering 95% of individuals who experience SCA outside of a hospital setting do not survive.
SCA vs. Heart Attack: Key Differences
While both sudden cardiac arrest (SCA) and heart attack are serious heart conditions, they differ significantly in their underlying causes and immediate effects:
- SCA:
- Electrical Problem: Primarily an electrical malfunction in the heart, causing it to abruptly stop beating effectively.
- Analogy: Similar to a power outage in your home, where the electrical supply is suddenly disrupted.
- Onset: Often sudden and unexpected, with no prior warning signs in many cases.
- Treatment: Requires immediate defibrillation (an electrical shock) to restore normal heart rhythm.
- Heart Attack (Myocardial Infarction):
- Circulation Problem: Occurs when blood flow to a part of the heart is blocked, typically by a blood clot.
- Analogy: Similar to a plumbing issue where a blockage prevents water flow.
- Onset: May be preceded by warning signs like chest pain, shortness of breath, or discomfort.
- Treatment: Often involves medications to dissolve the clot, procedures like angioplasty to open the blocked artery, or in some cases, surgery.
Key Takeaways
- Both SCA and heart attack are medical emergencies, but they require different immediate responses.
- Recognizing the distinction between these conditions is crucial for timely and appropriate intervention.
- While a heart attack can sometimes lead to SCA, they are distinct conditions with different underlying causes.
Individuals at Higher Risk of Sudden Cardiac Arrest (SCA)
While SCA can affect anyone, certain factors increase the risk:
- Low Ejection Fraction (EF):
- The EF measures how much blood the heart pumps out with each beat.
- A healthy heart typically pumps out 55% or more of its blood volume.
- An EF below 35% significantly increases the risk of SCA.
- Previous Heart Attack (Myocardial Infarction):
- Individuals who have experienced a heart attack are at a substantially higher risk of subsequent SCA.
- In fact, over three-quarters of individuals who die from SCA show evidence of prior heart attacks.
- Abnormal Heart Rhythms:
- Irregular heartbeats (arrhythmias) can disrupt the normal electrical activity of the heart and increase the risk of SCA.
- This includes conditions like atrial fibrillation, ventricular tachycardia, and others.
- Unexplained Fainting:
- Fainting episodes of unknown origin can be a warning sign of underlying heart problems, including an increased risk of SCA.
- Rapid Heart Rate (Tachycardia):
- Episodes of unusually fast heart rates, even when at rest, can be a risk factor for SCA.
- Family History:
- A family history of sudden cardiac death, heart failure, or other serious heart conditions can increase an individual's risk.