What is sudden cardiac arrest? (Part 1)

What is sudden cardiac arrest?

Sudden cardiac arrest or SCA occurs when the heart suddenly and unexpectedly stops beating thereby cutting off the blood supply to your brain and vital organs. To understand why this happens lets go back to the basics your learned in a high school anatomy class: our heart serves as the body's electrical system and is responsible for controlling both the rate and rhythm of the heart. When this fails to happen, irregular heart beats called Arrhythmias (pictured at right). These can cause the heart to be either too slowly or too fast or with an irregular rhythm. Some can stop pumping blood to the body -- this causes SCA.

What are the risk factors for SCA?

By far the biggest risk factor for the development of SCA is Coronary heart disease (CHD). Most people suffering from SCA have some degree of coronary heart disease; however, many people don't know they have CHD until a SCA event occurs. In many cases, it is "silent" meaning that it exhibits no signs or symptoms and goes undetected by health professionals. In many cases, victims have "silent" (undiagnosed) heart attacks prior to a SCA event. Patients who suffer a "silent" heart attack - also known as a Myocardial infarction (MI) - show none of the common symptoms associated with a heart attack.

Other risk factors include: 1) A personal history of arrhythmias [such as Atrial fibrillation (A-Fib)]; 2) A personal or family history of SCA or inherited disorders that put you at risk for experiencing an arrhythimias; 3) Substance abuse; 4) Heart attack; or 5) Heart failure.

Screening and prevention of SCA

Ways to prevent death from SCA are dependent on several factors: 1) The person already suffers from Sudden Cardiac Arrest; 2) The person has never had Sudden Cardiac Arrest, but is at an elevated risk for it; and 3) The person has never had Sudden Cardiac Arrest and has no known risk factors for developing it.

For people who have survived Sudden Cardiac Arrest

People who have previously experienced SCA are at a great risk of it happening again. Research has shown that surgical implantation of a Implantable cardioverter defibrillator (ICD) [pictured at right] reduces that chance of the patient dying from a second SCA. It is surgically placed under the skin in either the chest or abdomen and has wires that connect to the chambers of the heart. If a dangerous rhythm is detected, it will deliver a shock that will return the heart to a normal sinus rhythm.

For people at risk for a first occurrence of Sudden Cardiac Arrest

Persons with severe coronary heart disease (CHD) are at a higher risk for SCA -- particularly if they have already had a heart attack. Your doctor might prescribe a Beta blocker to aid in lowering your risk for SCA. They might also prescribe a statin drug for patients who have: A) Diabetes; B) Heart disease (or a previous stroke); or C) High LDL ("bad") cholesterol levels.

For people with no known risk for Sudden Cardiac Arrest

CHD appears to be the cause of SCA in most adults. It is also major risk factor in the development of angina pectoris (chest pain and/or discomfort). It can also contribute to the occurrence of heart attack and other related problems.

For additional information:

What is Coronary Heart Disease?

What is sudden cardiac arrest?

BIBLIOGRAPHY

National Institute of Health (2016). Coronary heart disease. Retrieved on February 16, 2016 from https://www.nhlbi.nih.gov/health-topics/coronary-heart-disease

National Institute of Health (2016). Sudden cardiac arrest. Retrieved on February 16, 2018 from https://www.nhlbi.nih.gov/health-topics/sudden-cardiac-arrest.