by Craig Weatherby
Heart failure is an all-too-common condition in which the heart can't pump enough blood to meet the body's needs.
Also known as congestive heart failure (CHF), this condition afflicts nearly six million people in the U.S., and kills some 300,000 Americans annually.
The most common type of CHF is called ischemic cardiomyopathy, which stems from clogged arteries and/or high blood pressure and can result from a heart attack.
(Ischemic means an insufficient blood supply, and cardiomyopathy refers to damaged heart muscle.)
A less common type of CHF is called “non-ischemic cardiomyopathy” or NICM, whose causes are less clear. (The CHF patients in the study we're reporting on today were diagnosed with NICM.)
Heart failure can involve either or both sides of the heart, but typically begins by impairing function in the heart's main pumping chamber, called the left ventricle.
Health authorities worldwide agree that the available evidence supports the value of fish and their omega-3 fatty acids for reducing the risk of second heart attacks, and the risk of sudden cardiac death.
It's been less clear whether fish and fish oil can help prevent or treat CHF, and in which contexts (CHF types and patient profiles) they may do the most good.
Now, the results of a small, year-long clinical trial add more evidence suggesting that fish fat may help improve key aspects of CHF in patients with the NICM type.
Italian-American study finds omega-3s may benefit heart failure patients
The new trial was conducted by scientists from Italy's University of Brescia and Chicago's Northwestern University.
The Italian researchers recruited 133 heart failure patients who were already receiving standard drug therapy – e.g., beta blockers – and divided them randomly into two groups:
A test group took 2 grams of omega-3-rich fish oil daily, while the other participants took identical placebo capsules.
The researchers compared pumping capacity in the participants' left ventricles – using echocardiography and cardiopulmonary exercise testing – at the start and end of the 12 month study.
At the end of the one-year trial, the omega-3 group showed five key advantages over the placebo group:
Pumping capacity in the left ventricle increased by 10.4 percent, in contrast to a five percent decline in the placebo group.
Peak VO2 – the maximum amount of oxygen your heart can provide to your muscles during sustained exercise – increased by 6.2 percent, in contrast to a 4.5 percent decline in the placebo group.
Exercise duration increased by 7.5 percent, in contrast to a 4.8 percent decline in the placebo group.
Their average score on the New York Heart Association's CHF-severity scale decreased from 1.88 to 1.61 (a good thing), but increased from 1.83 to 2.14 in the placebo group.
Hospitalizations related to CHF occurred in six percent of the fish oil group, versus 30 percent of the placebo group.
As the authors wrote, “Given these promising results, larger studies are in order to confirm our findings” (Nodari S et al. 2011).
To that, we say amen.
Lau DH, Psaltis PJ, Carbone A, Kelly DJ, Mackenzie L, Worthington M, Metcalf RG, Kuklik P, Nelson AJ, Zhang Y, Wong CX, Brooks AG, Saint DA, James MJ, Edwards J, Young GD, Worthley SG, Sanders P. Atrial Protective Effects of n-3 Polyunsaturated Fatty Acids: A Long Term Study in Ovine Chronic Heart Failure. Heart Rhythm. 2010 Dec 7. [Epub ahead of print]
Nodari S, Triggiani M, Campia U, Manerba A, Milesi G, Cesana BM, Gheorghiade M, Dei Cas L. Effects of n-3 Polyunsaturated Fatty Acids on Left Ventricular Function and Functional Capacity in Patients With Dilated Cardiomyopathy. J Am Coll Cardiol. 2010 Dec 29. [Epub ahead of print]
Teng LL, Shao L, Zhao YT, Yu X, Zhang DF, Zhang H. The beneficial effect of n-3 polyunsaturated fatty acids on doxorubicin-induced chronic heart failure in rats. J Int Med Res. 2010 May-Jun;38(3):940-8.