Re: debate

 Antiarrhythmic effects of the Prostaglandin (PG) precursors arachidonic and Linoleic acid were demonstrated on three models of experimental arrhythmias, whereas the fatty acids linolenic and oleic acid proved to be ineffective in these models. In ouabain-induced arrhythmias infusions of arachidonic acid (1,0 mg/kg/min) caused a strong antiarrhythmic effect in 80 percent of the animals. 

Actually this is easily explained.  As they mentioned the AA is a prostaglandin precursor.  And as I have pointed out many times the most common cause of arrhythmias is a lack of blood flow to the heart leading to ectopic pacemakers that throw the rhythm off.  Prostaglandins though dilate the blood vessels and thus increase blood flow going to the heart and reducing ectopic pacemakers.

Although the real question was whether or not AA increased the rick of atherosclerosis, not arrhythmias.  Atherosclerosis is more likely to lead to death than most arrhythmias.  So getting back to the original claims does AA contribute to heart attack and strokes?  The answer is yes.  It is those same prostaglandins that contribute to arterial inflammation.  Arterial inflammation in turn leads to cholesterol deposition on the arterial walls over time increasing the risk of heart attack and stroke.

In addition the AA was used in what is suspected to be relatively healthy animals.  Long term exposure to the high levels of AA though again leads to arterial plaque build up from arterial inflammation.  As arterial plaque builds up though, blood flow to the heart actually decreases leading to an increased risk of arrhythmias.  So the study can actually be considered misleading since it fails to take in to account the long term adverse effects of AA.  That would be like doing a study on the effects of caffeine on the adrenals and starting out with healthy individuals.  But they only give small doses of caffeine for a few days and come to the conclusion that caffeine has no adverse effects on the adrenals.  Of course caffeine does adversely affect the adrenals, but this goes to show how easy it is to manipulate studies to show what a person wants to show.  Just like that study failed to take in to account the long term effects of AA on the arterial lining and arrhythmias.