Sudden Cardiac Arrest (SCA) is a medical emergency that often strikes without warning and can lead to devastating consequences if not promptly addressed. In this blog, we'll explore the underlying causes of SCA, its relationship with various heart conditions, and some critical facts highlighting the importance of understanding and responding to this life-threatening event. By comprehensively understanding SCA, its causes, and its impact, we can better prepare ourselves to recognize the warning signs and take appropriate action to save lives.
What is Sudden Cardiac Arrest?
Sudden cardiac arrest occurs when the heart stops abruptly and unexpectedly. When this happens, blood flow to the brain and other organs stops, and the person collapses. Within seconds, they lose consciousness and stop breathing. Without immediate CPR and medical treatment, sudden cardiac arrest can be fatal.What Causes Sudden Cardiac Arrest
Various heart conditions and factors can trigger cardiac arrest. Most cardiac arrests happen when the heart's electrical system malfunctions due to a diseased heart. This malfunction leads to abnormal heart rhythms like ventricular tachycardia or ventricular fibrillation. Ventricular fibrillation is the most common cause and occurs when the electrical impulses that control heartbeats become erratic, causing the heart to beat erratically and chaotically. In some cases, cardiac arrests are also caused by an extremely slow heart rhythm (bradycardia). These irregular heartbeats can be life-threatening.Other causes of SCA include:
- Scarred heart tissue - This can result from a previous heart attack or other causes. A heart with scarring or enlargement is at risk of developing life-threatening ventricular arrhythmias. The initial six months following a heart attack represent a high-risk period for sudden cardiac arrest in patients with atherosclerotic heart disease.
- Thickened heart muscle (cardiomyopathy) - Heart muscle damage may stem from high blood pressure, heart valve disease, or other factors. A damaged heart muscle increases the risk of sudden cardiac arrest, mainly if heart failure is also present. For more information, explore cardiomyopathy.
- Heart medications - In some situations, certain heart medications can predispose individuals to arrhythmias that lead to sudden cardiac arrest. Interestingly, antiarrhythmic drugs designed to treat arrhythmias can occasionally cause ventricular arrhythmias even at normal doses, a phenomenon known as a
- "proarrhythmic" effect. Drastic fluctuations in blood potassium and magnesium levels (potentially due to diuretic use) can also lead to life-threatening arrhythmias and cardiac arrest.
- Electrical abnormalities - Conditions such as Wolff-Parkinson-White syndrome and Long QT syndrome can provoke sudden cardiac arrest in children and young adults.
- Blood vessel abnormalities - These uncommon cases typically involve the coronary arteries and aorta. Intense physical activity, which causes adrenaline release, can trigger sudden cardiac arrest in the presence of such abnormalities.
- Recreational drug use - can occur to healthy individuals abusing stimulants or opiates.
- Other potential causes include electrical shock, drowning, suffocation, extreme emotional stress, and physical exertion.