Sudden Cardiac Death (SCD) is responsible for numerous deaths in the U.S. and other countries around the world. It is not the same as a heart attack. A heart attack normally occurs when advanced atherosclerosis (clogging of the arteries) slowly starves the heart causing irreversible damage. The heart finally cannot function properly and stops. Sudden cardiac death occurs when the electrical impulses that control heart function become erratic resulting in an irregular heartbeat (arrhythmia). When the arrhythmia is severe enough the heart suddenly stops, starving the brain of needed blood. Death often follows quickly unless emergency care is administered immediately. Often sudden cardiac death occurs when no other heart disease is detected.
It has long been understood that eating fish can reduce the likelihood of heart attack and other cardiovascular diseases. The reason? Fish, especially cold-water fatty fish, is high in two omega-3 polyunsaturated fatty acids (PUFA). These two fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega-3 has been shown to reduce the build-up of artery clogging atherosclerosis and keep blood platelets from sticking together thus reducing the risk of heart attack and stroke.
But more recent studies suggest that omega-3 fatty acids also have an effect on the dangerous arrhythmias that can cause sudden cardiac death by regulating the impulses that control heart rhythm.
One study involved the use of myocytes (cells that beat independently). By adding the free fatty acids to these cells arrhythmias were aborted. When the fatty acids were extracted from the myocytes the arrhythmias would reoccur thus indicating that omega-3 fatty acids have a stabilizing effect on heart rhythm. The apparent mechanism for controlling rhythm involved cell ion channels, proteins that control the movement of sodium, calcium and potassium ions across the membrane of the cell.
Another study, conducted by Danish researchers, examined the relationship between heart rate variability and omega-3 fatty acids in healthy subjects. It had already been determined that heart arrhythmias could be positively impacted in patients who were recent heart attack victims. These researchers wanted to determine if people otherwise free of heart disease could gain the same arrhythmia controlling benefits from omega-3 fatty acids.
Sixty healthy adults were randomly divided into three groups. The first group received daily supplements containing 6.6 g of omega-3 (containing 3.0g EPA and 2.9g DHA). Group two received 2.0g of omega-3 (containing 0.9g EPA and 0.8g DHA). The remaining group received only an olive oil placebo. The supplements were given for 12 weeks. Before and after the supplements were consumed heart rate variability and blood cell fatty acids were measured. It was found that heart rate variability was favorably influenced by the amount of omega-3 consumed. In other words, the more omega-3 one consumed the higher the heart rate variability, especially in men with low heart rate variability before supplementing.
The researchers concluded that omega-3 fatty acids positively affected heart rate variability thus having a protective effect on heart function. These finding were similar to those of earlier studies showing that omega-3 positively affects heart rhythm in patients who had suffered a previous heart attack. Since sudden cardiac death is the result of erratic heart rhythm, omega-3’s heart protective qualities show great promise in the fight against sudden cardiac arrest. The mechanical studies completed by these and other researchers seemed to confirm other studies that the oral ingestion of fish and fish oils provide prophylaxis for the prevention of fatal cardiac arrhythmias when taken regularly in small amounts. In simple terms, consuming fish and fish oil supplements can save lives.