DALLAS, April 9 Daily supplements of a fatty acid found in fish oil halves the risk of sudden death in heart attack survivors, researchers report in todays Circulation: Journal of the American Heart Association.
Previous research has found that eating oily fish such as tuna and salmon can reduce the risk of sudden cardiac death caused by a particular type of irregular heartbeat. This study suggests fish-oil supplements, rather than dietary fish oil, could be a therapy without side effects for heart patients.
The finding is from an analysis of data from the GISSI-Prevenzione trial. That study found that 1 gram daily of n-3 polyunsaturated fatty acids (PUFA) found in fish oil and known also as omega-3 fatty acids significantly reduced the risk of death overall and sudden death in people who had heart attacks.
The benefits were not due to changes in cholesterol levels or by reducing potentially fatal blood clotting.
The new analysis reveals that the lower mortality rate for the n-3 PUFA patients, compared with patients who got a placebo, resulted largely from a 42 percent reduction in sudden cardiac deaths at three months follow-up.
That was a surprise, says lead author Roberto Marchioli, M.D., head of the laboratory of clinical epidemiology of cardiovascular disease at Consorzio Mario Negri Sud, a research institute in Santa Maria Imbaro, Italy. The risk of death, and sudden death, is higher in the first months after a heart attack. It is exactly in this period that the effect on sudden death was noted.
The analysis also shows that the lifesaving benefit of n-3 PUFA is likely due to reducing episodes of potentially fatal irregular heartbeats, called arrhythmias. About 250,000 people in the United States die each year from coronary heart disease without reaching the hospital alive. Most of these deaths are probably due to sudden death caused by an arrhythmia.