Magnesium is essential to heart health. Studies suggest a possible association between a modestly lower risk of CHD in men and increased magnesium intake. In one study of women, higher dietary intakes of magnesium were associated with a lower risk of sudden cardiac death. Magnesium helps maintain a normal heart rhythm and is sometimes given intravenously (IV) in the hospital to reduce the chance of atrial fibrillation and cardiac arrhythmia (irregular heartbeat). People with congestive heart failure (CHF) are often at risk for developing cardiac arrhythmia. For this reason, your doctor may decide that magnesium should be a part of the treatment of CHF. One well designed study found that taking magnesium orotate for a year reduced symptoms and improved survival rates compared to placebo in people with CHF. Magnesium and calcium work together at very precise ratios to ensure your heart functions properly. If you have a cardiac history, talk to your doctor before taking magnesium supplements.

Results of studies using magnesium to treat heart attack survivors, however, have been mixed. Some have reported lower death rates, as well as fewer arrhythmias and improved blood pressure when magnesium is used as part of the treatment following a heart attack. But one study found that magnesium slightly increased the risk of sudden death, chance of another heart attack, or need for bypass surgery in the year after a heart attack. If you have had a heart attack, your doctor will decide if magnesium supplementation, either IV or orally, is right for you.