For people with heart disease who are already taking statins, taking a high dose of a specific fish oil component called EPA (at least 1,800 mg a day) may slow down the buildup of plaque in their heart arteries by about 72% over a year or two, compared to not taking any fish oil at all.

For people with heart disease who are already taking statins, taking a high dose of EPA (a type of fish oil) seems to lower 'bad' cholesterol more than lower doses of other omega-3s—but even with that extra cholesterol drop, something else about EPA is still helping reduce artery plaque.

People with heart problems who take a high dose of EPA, a type of fish oil, tend to have less of a dangerous type of plaque in their arteries over a year or two, while those who don’t take it tend to have more of this plaque.

People with more of the good omega-3 fats (EPA and DHA) in their red blood cells tend to have less heart disease and do better over time if they already have heart problems.

Taking fish oil supplements with EPA and DHA might help keep your blood from clotting too easily, which could lower your chance of having a heart attack or stroke if you already have heart disease.