At the end of 2 years, however, there was a reduction in mortality of 29% in the 1015 men who had received advice to eat oily fish, at least 200 to 400 g portions twice weekly, compared with the 1018 men who had not received such advice. There were no significant differences in ischemic heart disease events between the fish advice and the no-fish advice groups, as more nonfatal infarcts occurred in the fish advice group. The mortality difference in favor of fish advice appeared early and persisted up to 2 years. Over the 2 years there were no significant differences in levels of total cholesterol. This study was published before the antiarrhythmic effects of fish oils were generally known, but the reduced mortality in those advised to eat fish despite an increase in myocardial infarctions in this cohort, suggests that the findings resulted from a reduction in arrhythmic deaths. With some 50-60% of sudden cardiac deaths (deaths within one hour of an acute myocardial infarction) attributed to sustained ventricular arrhythmias, this present interpretation seems credible. Patients were still experiencing myocardial infarctions, but were not dying as frequently from them.