Omega-3 fatty acids and sudden arrhythmic death.

Cardiovascular disease is the leading cause of death in developed countries. In Canada, in 1999, cardiovascular disease was responsible for 36% of all deaths. Ischemic heart disease accounts for the greatest percentage of these deaths (20% of all deaths), half of which are due to the acute effects of myocardial infarction. The other half are related to the late manifestations and complications of myocardial infarction. Once coronary arteriosclerosis has reached the point where it results in myocardial infarction, two main complications can ensue, loss of myocardial function and disturbance of cardiac rhythm. Progressive loss of myocardial pump function results in the syndrome of congestive heart failure. Abnormalities of the heart rhythm result in ventricular fibrillation, which is the direct cause of sudden death. Congestive heart failure rates have been easy to track because of the frequent need for hospitalization and we know from analysis of administrative databases that the annual rate of death from heart failure is about 2.5% in Canada. Sudden death, however most often occurs at home and without warning, making it much more difficult to quantitate its impact. However, the most conservative estimates suggest that no less than 25% of deaths in patients with a diagnosis of ischemic heart disease are due to ventricular fibrillation.