For decades, researchers have been intrigued by the potential heart-healthy benefits of consuming omega-3 fatty acids found in fish oil. Now, a new analysis provides "firm evidence" that fish oil affects the electrical workings of the heart—including heart rate, a major risk factor for sudden death. Reporting in Circulation, the journal of the American Heart Association, researchers say a review of pooled data from 30 randomized and controlled studies shows that fish oil reduces heart rate, particularly among those with higher baseline rates or on the therapy for at least 12 weeks. A similar reduction was noted in people taking fish oil doses ranging from 800 milligrams to 15 grams per day.

Heart Attack or Heartburn?

While chest pain may indicate an underlying heart problem, many times it does not. The following diagnostic test may someday help physicians identify patients at high cardiac risk versus those suffering with heartburn, muscle pain, and other types of chest discomfort.

A sophisticated imaging technique called the SPECT scan detects heart damage up to 30 hours after blood flow is briefly disrupted. Scientists say that the healthy heart burns fat molecules as its main fuel. When blood flow is interrupted, however, the heart uses glucose (blood sugar) instead. In the preliminary study, researchers used an experimental radioactive tracer called iodofiltic acid I 123 (trade name Zemiva) to detect this use of glucose.

Fitness Counts

Regular exercise can greatly reduce the risk of dying from heart disease, even when cholesterol levels are high, scientists report.

Researchers at Queens University in Kingston, Ontario, admit they were surprised by the risk-reducing impact of being physically fit. In their study, those with the highest cholesterol levels lowered their mortality risk by 50 percent by exercising for 30 minutes, four or five times weekly. Likewise, men in the "moderate" risk category who exercised cut their risk from six times to three times that of fit men in the low-risk group.

The ten-year study followed 19,125 men ages 20 to 79.

Water pills for Hypertension

When ACE inhibitors or calcium channel blockers fail to curb high blood pressure, a new study from Indiana University School of Medicine suggests that adding a low-cost water pill is more effective than increasing the doses of current medications.

Water pills, or diuretics, help reduce blood pressure by stimulating the kidneys to produce more urine, expelling fluid and minerals such as sodium.

Q&A Corner: The BUN Test

1. What is a BUN test? This blood test measures the level of blood urea nitrogen, a chemical that is produced when the body breaks down protein molecules. Urea is formed in the liver and excreted by the kidneys.

2. Why do doctors order the test? BUN is an important indicator of kidney function and overall health. It is part of a basic group of tests that is widely used for routine testing and to monitor kidney function in patients with chronic diseases such as diabetes and congestive heart failure.

3. Why is my BUN above normal? Elevated levels may signal kidney problems or GI bleeding. Burn patients have a high BUN due to extensive tissue and protein damage. Test results increase with age and tend to be slightly above normal in people over age 70.

4. Why is my BUN below normal? Low levels may be linked to liver problems, poor nutrition, and overhydration.

5. How can I help ensure the most accurate results? Watch your protein intake for several days before the test. High-protein diets may cause abnormally high BUN levels; very low-protein diets can cause abnormally low results. Other food and fluids do not affect BUN levels.