Studies To Examine Whether Fish Oils Can Prevent Arrhythmias

	October 6, 1999 - At least 3 clinical trials are being launched to
test fish oil to prevent heart arrhythmias, which are life-threatening
disturbances of heart rhythm. Two of the trials are in the USA and one is in
Europe. They were announced at the 21st Congress of the European Society of
Cardiology held last week.
	Recent studies of heart tissue have confirmed that omega-3
polyunsaturated fatty acids (PUFAs), usually derived from fatty fish or fish
oil, can help stabilize heart rhythm. The effect operates on the sodium and
calcium channels to the heart and is not seen with other polyunsaturated
fatty acids such as the omega-6 PUFAs.
	The first of the 3 trials, a 2 year study, has been set up under
the National Institutes of Health by a group including nutrition specialists
and cardiologists. A positive outcome from this study could have implications
for preventing sudden cardiac death, which is often linked to heart rhythm
disturbance. Even though some newer anti-arrhythmia drugs can be effective,
it's more practical to find preventive measures that are safe, inexpensive
and well tolerated.
	Commenting on these studies, Dr. Peter Schwandt, a leading European
cardiologist, called the potential use of fish oils "an idea whose time has
come. There is considerable research indicating a positive effect of PUFAs on
endothelial function and on high blood pressure. In fact, we are already
giving omega-3 long chain PUFAs in dietary supplements to patients with high
triglyceride levels."
	However, Schwandt did not recommend that fish oils be given on a
preventive basis to patients at high risk for arrhythmia. "We need clinical
support for such a step, and these trials will help provide that," he said.
	The randomized controlled trial at OHSU, for which 26 patients have
already been enrolled, will test fish oil capsules at a dose of 2 grams a day
versus a placebo. The study will enter 200 patients to be followed over a 2
year period.
	Patients are being recruited from those who survive an episode of
either ventricular tachycardia (VT) or ventricular fibrillation (VF) and who
then got an ICD, or who have an ICD and then had an event of arrhythmia.
This seems a good trial design, as there is an increased probability of 50%
that patients who survive such an event will have another one within a year.
ICDs record all arrhythmic events.
	Following an electrophysiology study, patients will be selected at
random to receive either fish oil capsules or placebo. Patients will then
receive check-ups at 3 month intervals over a 2 year period.
	Two other trials are also being started. Alexander Leaf of
Massachusetts General Hospital is planning a 2 year study with 400 patients
using fish oil or placebo. A multi-center trial in Europe headed by Dr. Evert
Schouten is also being planned.