Magnesium - atrial fibrillation
Magnesium - atrial fibrillation
Hi Peter:
A fairly common complication from any open heart surgery is atrial fibrillation. It can occur in up to 60% of patients having heart valve surgery. Magnesium has been shown to lessen these occurrences. You should ask your surgeon for his views on the use of magnesium before, during & after surgery.
http://my.webmd.com/roundtable_printing/916442
New Magnesium Regimen Reduces Incidence of Atrial Fibrillation After CABG
NEW ORLEANS (Reuters Health) Jan 31 - The incidence of atrial fibrillation, a common and dreaded complication of coronary artery bypass grafting (CABG), is reduced when a novel magnesium regimen is administered, according to study findings presented Tuesday at the 37th annual meeting of The Society of Thoracic Surgeons.
Dr. Huseyin Cem Alhan and colleagues, from Acybadem Hospital, in Istanbul, Turkey, assessed the ability of magnesium to prevent postoperative atrial fibrillation by randomizing 200 patients undergoing CABG to receive 1.5 g of magnesium sulfate in 100 mL 0.9% saline or saline alone, 1 day before, during, and 4 days after surgery. Patient demographics were similar between the groups.
The researchers found that 2% of magnesium-treated patients experienced postoperative atrial fibrillation, significantly fewer than the 21% of untreated patients who manifested this arrhythmia.
"Many other studies have shown that magnesium has an effect on atrial fibrillation, but the appropriate dose and timing of infusion was not clear," Dr. Alhan told Reuters Health. "While many patients are hospitalized prior to their surgery, we found that even patients who do not receive the preoperative dose still have lower rates of atrial fibrillation."
"There are no contraindications to magnesium therapy, we give it to patients with normal as well as low magnesium levels," Dr. Alhan stated. "In the elderly it has been shown that patients may be total body magnesium deficient, but have normal serum levels," he explained. "We are not sure if the therapeutic mechanism is replenishment of a deficiency or a pharmacologic effect of the drug."
"Atrial fibrillation is not the most serious complication after cardiac surgery, but it is the most common," Dr. Alhan pointed out. "It has a strong impact on the hospital length of stay and therefore on the cost associated with cardiac surgery," he noted. "The patients who received magnesium in this study went home earlier," Dr. Alhan emphasized.
Other studies have also shown magnesium benefits heart patients"
http://www.yourhealthbase.com/magnesium.html
Summaries of the latest research concerning magnesium
Magnesium benefits heart patients
LOS ANGELES, CALIFORNIA. The health of the lining (endothelium) of the blood vessels is crucial to cardiovascular health. There is considerable evidence that a dysfunction of the endothelium can lead to atherosclerosis and subsequent coronary artery disease (CAD). Researchers at the Cedars-Sinai Medical Center now report that oral magnesium supplementation can substantially reduce endothelial dysfunction and improve exercise tolerance in CAD patients. The randomized, prospective, double blind, placebo- controlled trial involved 50 patients (41 men and 9 women with a mean age of 67 years) who had been diagnosed with CAD either by angiography or after having had a heart attack. Initial evaluation of the patients showed that 72 per cent of them had a lower than normal tissue magnesium level. The tissue magnesium level was measured in sublingual epithelial cells scraped from under the tongue or from between the gums and the upper or lower lips. Magnesium levels measured in sublingual cells have been found to correlate well with levels found in heart tissue.
The patients were randomized to receive either a placebo or 365 mg of elemental magnesium (in the form of oxide and carbonate) daily. After six months tissue magnesium concentration was measured again, a treadmill test was performed, and endothelial function was evaluated using ultrasound. Patients in the magnesium group increased their intracellular magnesium level by about 10 per cent to reach the lower limit of the normal range. Endothelial function (flow-mediated vasodilation measured at the brachial artery) improved by 25 per cent in the magnesium group as compared to a 4.5 per cent decline in the placebo group over the six-month period. The magnesium supplemented group also performed significantly better on the treadmill test than did the placebo group. Not only did they improve their exercise duration as compared to baseline and the placebo group, but it was also highly significant that none of them experienced an arrhythmia during the test whereas four patients in the placebo group did.
The researchers suggest that magnesium may protect the heart against the detrimental effects of a calcium overload and may improve intracellular ATP production and glucose use. They conclude that oral magnesium supplementation improves exercise tolerance and endothelial function in coronary artery disease patients. NOTE: This study was partially funded by Asta Medica Company, Inc. (Vienna, Austria) the manufacturer of the magnesium supplement.
Shechter, Michael, et al. Oral magnesium therapy improves endothelial function in patients with coronary artery disease. Circulation, Vol. 102, November 7, 2000, pp. 2353-58
Magnesium and heart surgery in children
CHARLESTON, SOUTH CAROLINA. Administration of magnesium has been shown to reduce the incidence of heart surgery related arrhythmias in adults. It has also been observed that the magnesium level in the right atrial tissue is lower in adult patients with postoperative cardiac arrhythmias compared to patients without arrhythmias after heart surgery. Researchers at the Department of Pediatric Cardiology at the Medical University of South Carolina now report that children undergoing surgery for congenital heart defects develop a severe magnesium deficiency immediately after surgery. This deficiency is associated with a greater incidence of a serious arrhythmia (junctional ectopic tachycardia) and can be prevented by an infusion of magnesium sulfate immediately after completion of the surgery.
The study involved 28 pediatric patients (average age of five years) who were scheduled to undergo heart surgery with cardiopulmonary bypass (CPB). The patients were randomly assigned to receive an infusion of magnesium (30 mg/kg body weight of a five per cent saline solution administered over a period of 10 minutes) or an infusion of saline solution immediately after cessation of CPB. Blood levels of magnesium were measured in all patients before surgery, before CPB, after CPB, upon arrival in the intensive care unit (ICU), and then every four hours for 24 hours. Each patient was also monitored for arrhythmias for 24 hours with a Holter monitor.
Comparison of the results for the two treatment groups revealed that the magnesium level was significantly below normal in patients who had received saline solution (placebo) when they arrived in the ICU and for the following 20 hours. Patients who had received the magnesium infusion, on the other hand, had magnesium levels that were well within the normal range (1.6 to 2.3 mg/dL) when tested in the ICU and for the following 20 hours. There were no incidences of junctional ectopic tachycardia in the magnesium group, but four (27 per cent) of the patients in the placebo group experienced this serious arrhythmia. It stopped after a magnesium infusion. The researchers "recommend routine measurement of magnesium levels after CPB in children undergoing heart surgery, with timely magnesium supplementation in the postoperative period." [49 references]
Dorman, B. Hugh, et al. Magnesium supplementation in the prevention of arrhythmias in pediatric patients undergoing surgery for congenital heart defects. American Heart Journal, Vol. 139, No. 3, 2000, pp. 522- 28
Lack of magnesium and heart disease
ATLANTA, GEORGIA. Researchers at the Centers for Disease Control and Prevention have just released the results of a study which shows a clear association between low blood serum levels of magnesium and the risk of dying from heart disease and other causes. The study involved 12,000 participants who were enrolled between 1971 and 1975 and followed for 19 years. At the end of the study 4282 of the participants had died, 1005 of them from ischemic heart disease. Compared with participants having a magnesium level of 0.80 mmol/L or less the risk of dying from heart disease was 21 per cent lower among participants with magnesium concentrations between 0.80 and 0.84 mmol/L and 31 to 34 per cent lower among participants with concentrations higher than 0.84 mmol/L. This correlation held true even after adjusting for other major variables such as age, sex, race, education, smoking status, systolic blood pressure, use of anti- hypertensive medications, body mass index, history of diabetes, alcohol use, and the level of physical activity. The researchers estimate that about 11 per cent of the almost 500,000 deaths from coronary heart disease which occurred in 1993 in the United States can be attributed to low magnesium levels. They also point out that a recent study (NHANES I) found that about 23 per cent of the people evaluated had magnesium levels below 0.80 mmol/L. Other studies have shown that a large proportion of the American population does not consume the recommended daily allowance of magnesium (350 mg/day for men and 280 mg/day for women).
Ford, Earl S. Serum magnesium and ischaemic heart disease: findings from a national sample of US adults. International Journal of Epidemiology, Vol. 28, August 1999, pp. 645-51
Got Magnesium? Those With Heart Disease Should
Blood Vessels Improve, Ability to Exercise Increases
By Janis Kelly
WebMD Medical News
Reviewed by Dr. Gary D. Vogin
Nov. 9, 2000 -- Every cell in the body needs magnesium. It helps keep muscles strong and nerves alert. And a new study in the journal Circulation suggests that daily magnesium supplements can even help an ailing heart.
Lead author C. Noel Bairey Merz, MD, tells WebMD that magnesium supplements enabled heart disease patients to exercise for longer periods and appeared to protect their hearts from the stress of exercise. Magnesium also restored some of the blood vessels' ability to open up when the body needs more blood. Merz is director of the preventive and rehabilitative cardiac center at Cedars-Sinai Medical Center in Los Angeles.
Half of the patients in the study took a supplement containing 365 mg of magnesium twice a day for six months. The other half took a placebo. Merz tells WebMD that at the end of the study, the patients who took magnesium had better blood vessel function and their hearts showed less stress during treadmill exercise compared to the placebo group. Nearly three-quarters of the patients were magnesium-deficient at the beginning of the study, but their levels rose to nearly normal by the end.
So what is it about magnesium that makes it such a friend to the body? It could be that magnesium helps the body's cells fend off stress. Magnesium-deficient cells also are more vulnerable to injury, and patients with heart disease may have greater need for magnesium, Merz says.
Carla A. Sueta, MD, PhD, who was not involved in the study, says, "we probably should move toward routine screening" for all patients with heart disease and offer supplements to all those found to be deficient. She cautions that the simple blood test available to doctors is not an accurate measure of magnesium levels. If the tests results are low, magnesium levels are probably very low in reality, so even someone with normal levels may still need supplements. Sueta is associate professor of medicine at the University of North Carolina at Chapel Hill, N.C.
Similar magnesium supplements are available over-the-counter in the U.S., but they might not provide similar benefits. "The product we used is from Germany, where supplements of this kind are regulated and quality is monitored," Merz says. "Because that is not the case in the U.S., it is impossible to know what you are getting in a supplement, or even whether it contains any magnesium at all. Patients who decide to try magnesium supplements available in the U.S. are probably fairly safe unless they have kidney problems," according to Merz.
However, he does suggest that people "follow the dietary recommendations to eat five to seven helpings of fruits or vegetables and two or three of nonfat dairy products every day. If everyone did that, we probably would not see the levels of magnesium deficiency we often find."
The most important food sources of magnesium are green vegetables like spinach, nuts, seeds, and some whole grains.
The research was funded in part by Asta Medica Co. Inc., manufacturer of the magnesium supplements used in the study.
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