A raft of clinical evidence has linked consumption of omega-3 fatty acids from fish oils to a reduced risk of sudden cardiac death, but a new study suggests that in some patients with life-threatening abnormal heart rhythms they may actually do more harm than good. The surprising results, published today in the Journal of the American Medical Association (vol 293, pp2884-2891), were obtained from a randomized controlled trial involving 200 patients with an implantable cardioverter defibrillator who had suffered a recent episode of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). VT is an accelerated heart beat initiated within the ventricles, that may prevent the heart from pumping enough blood through the body. Wheras the normal heart rate is 60 to 100 beats per minute, in VT patients it may be 160 to 240 bpm.VT can occur independently of any apparent heart disease, or following a heart attack or surgery. It can develop into VF, the primary cause of sudden cardiac death, in which the heart ceases to act like a pump due to irregular electrical activity and ventricular contraction. Based on the results of the new study, the researchers recommend that patients who would have qualified for inclusion in the study group to avoid taking fish oil supplements.
