Here's some excerpts on magnesium:
From:
http://www.chfpatients.com/stew/minerals.htm#magnesium
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Magnesium and Heart Patients
October, 1993 - Magnesium plays an important role in the cardiovascular system. Too-little magnesium has been linked with heart arrhythmia, increased death rate in CHF patients, and an increased death rate after acute heart attack. The research shows that magnesium supplements in these situations may be good for treating and preventing life-threatening arrhythmias. Magnesium supplements can be given safely either orally or by IV, depending on the situation.
Title: Magnesium in congestive heart failure, acute myocardial infarction and dysrhythmias.
Source: J Cardiovasc Nurs 8 (1): 19-31 (Oct 1993)
PMID: 8106895, MUID: 94149478
Diuretics Deplete Magnesium
July, 1994 - Compared to 31 healthy people of the same age, muscle levels of magnesium and potassium were very low in 76 patients who had been on diuretics for 1 to 17 months. Thirty-six patients with low muscle magnesium levels took magnesium hydroxide pills for 2 to 12 weeks (20 people) or 26 weeks (16 people).
After 2 to 12 weeks, muscle magnesium levels were higher but not back up to normal. After 26 weeks, the muscle levels of magnesium had been brought up to normal in most cases.
Oral magnesium supplements can restore normal magnesium levels in people who are low due to diuretics. However, a patient must take oral magnesium supplements for 6 months before reaching normal levels.
Title: Oral magnesium supplementation to patients receiving diuretics--normalization of magnesium, potassium and sodium, and potassium pumps in the skeletal muscles
Authors: Dorup I, Skajaa K, Thybo NK
Source: Ugeskr Laeger 156 (27): 4007-4010 (Jul 1994)
PMID: 8066894, MUID: 94345886
Digoxin Depletes Magnesium
1991 - Digoxin decreases magnesium in the cells and causes a lot of magnesium loss through the urine. Magnesium levels that are too low caused by diuretic use are very common in people also taking digoxin. Since low magnesium levels can lead to digoxin levels that are too high, both levels should be carefully watched - magnesium and digoxin.
Not only does a low magnesium level contribute to heart arrhythmias, it causes increased sensitivity to digoxin. Low magnesium also interferes with digoxin's ability to control atrial fibrillation.
Sources:
Toffaletti J. Analyt Chem 1991 63(12):192R-194R
al-Ghamdi SM, et al. Am J Kidney Dis 1994 Nov;24(5):737-752
Young IS, et al. Br J Clin Pharmacol. 1991 Dec;32(6):717-721
Lewis R, et al. Br J Clin Pharmacol. 1991 Feb;31(2):200-203.)
IV Magnesium For Arrhythmia
September 18, 1997 - Low magnesium levels are common in bypass surgery patients and are a risk factor for heart arrhythmia. IV magnesium avoids the side effects of most other drugs and reduces heart rate. The effects of IV magnesium are seen in patients with low magnesium and in those with normal magnesium levels, suggesting that magnesium has a drug-like action.
Magnesium used alone is better than digoxin for controlling ventricular response in a-fib; the two together control heart rate better still. Magnesium is as effective as IV amiodarone in controlling heart rate and it may be better for cardioversion in atrial tachyarrhythmias. IV magnesium has been reported to successfully cardiovert atrial arrhythmia.
There is evidence for using magnesium to prevent atrial arrhythmia after bypass surgery. Dr. Fanning studied a-fib in a trial with 99 patients, and patients receiving magnesium did much better. When patients have new a-fib after bypass surgery, we first look for reversible causes and then use an IV dose of 12 mmol of magnesium over a one hour period, followed by another 60 mmol over a 24 hour period, before we use other anti-arrhythmic drugs.
Source: Letter to the Editor of the New England Journal of Medicine
Title: Magnesium to Fight Arrythmias After Cardiac Surgery
Authors: William J.C. Hobbs, Alan Fitchet, and Lawrence Cotter
Magnesium For CHF
September, 1996 - Electrolyte balance is important to the heart's stability, especially in heart failure. Magnesium is hard to study because it is so hard to accurately measure a person's magnesium level. The magnesium level in your blood represents less than 1% of total body magnesium stores.
Magnesium is important in several enzyme reactions necessary for your heart's stability and proper functioning. Low magnesium level is common and is related to complications of heart failure. Typical CHF therapy (digoxin, diuretics and ACE inhibitors) changes your body's magnesium balance.
Magnesium supplements - both by pill and also in higher prescription doses for serious deficiency - improve blood flow and arrhythmias. Magnesium levels are almost never toxic unless the patient has very poor kidney function.
Proper magnesium levels in heart cells are crucial in maintaining stable heart and electrical function. In heart failure patients, proper magnesium level indicates a better prognosis because they relieve arrhythmias, digitalis poisoning and blood flow problems.
Title: Significance of magnesium in congestive heart failure.
Authors: Douban S, Brodsky MA, Whang DD, Whang R
Source: Am Heart J 1996 Sep;132(3):664-671
PMID: 8800040, UI: 96393253
Low Magnesium and EF
September, 1997 - To see if low magnesium levels contribute to arrhythmias, we measured tissue magnesium levels (among other things) in 40 patients with arrhythmias. Magnesium was measured in sublingual tissue via x-ray. Patients with an EF over 40% had much higher tissue magnesium levels than patients with lower EFs.
Low tissue magnesium levels may indicate high risk for certain arrhythmias, especially in patients with poor left ventricular function. However, moderately low magnesium levels may not matter to those with monomorphic ventricular tachycardia.
Title: Tissue magnesium levels and the arrhythmic substrate in humans.
Authors: Haigney MC, Berger R, Schulman S, Gerstenblith G, Tunin C, Silver B, Silverman HS, Tomaselli G, Calkins H
Source: J Cardiovasc Electrophysiol 1997 Sep;8(9):980-986
PMID: 9300294, UI: 97445409
Low Magnesium and EF
August 30, 1999 - Low levels of magnesium in the blood are linked to higher risk of death from ischemic heart disease. Using 19 years of data from the National Health and Nutrition Examination Survey, Dr. Earl Ford analyzed ischemic heart disease deaths in over 12,000 people. He also studied all-cause mortality in 13,000 people. In the 2 groups combined, the number who were hospitalized for ischemic heart disease was 2,637 and the number of patients who died of ischemic heart disease was 1,005.
Dr. Ford found that "low blood magnesium level - independent of other factors - was associated with all-cause mortality and death from ischemic heart disease." People with proper blood magnesium levels "had 21% to 34% less risk of dying from ischemic heart disease." About 23% of patients had too-low levels.
The recommended dietary allowance of magnesium is 350mg for men and 280mg for women, but according to the results of the National Health Survey II, from 1988-1991 the average daily magnesium intake was too low.
Source: Int J Epidemiol 1999;28:645-651
IV Magnesium, CHF and Arrhythmia
June, 1993 - Intravenous magnesium is an effective treatment for certain ventricular tachycardias. In patients with congestive heart failure, low blood magnesium levels are commonly seen in frequent arrhythmias with high death rates. This suggests that giving magnesium may lower the risk of arrhythmia and death in CHF patients.
We studied the effect of IV magnesium on the frequency of ventricular premature depolarizations in 40 CHF patients. These patients were heart class 2 to class 4. Each patient had a 6-hour EKG recorded while engaging in normal activities. The study started within one week of the EKGs. Over a one-hour period, 0.2 mEq/kg of IV magnesium was given. A repeat EKG was then done.
In patients for whom IV magnesium greatly increased their blood magnesium levels, arrhythmias went way down. In patients for whom the IV magnesium caused only a slight increase in blood magnesium levels, arrhythmias were slightly more frequent. In patients who had high arrhythmia levels before the magnesium, treatment reduced their arrhythmia rate by 50%. Overall, there was a 20% decrease of arrhythmias in all patients.
Title: Effects of intravenous magnesium sulfate on arrhythmias in patients with congestive heart failure.
Author: Gottlieb SS, Fisher ML, Pressel MD, Patten RD, Weinberg M, Greenberg N
Source: Am Heart J 1993 Jun;125(6):1645-1650
PMID: 8498307, UI: 93269785
IV Magnesium and Arrhythmia In CHF
February, 1994 - There is a high rate of ventricular arrhythmia and sudden death in patients with heart failure. We studied the immediate effect of IV magnesium chloride on the frequency and severity of arrhythmia in 30 CHF patients. This was a double-blind, placebo-controlled crossover study. The average EF was 23%. No patient had a history of severe arrhythmia and none were taking anti-arrhythmic drugs, calcium channel blockers or beta-blockers.
Patients took either placebo or 0.3 mEq/kg magnesium chloride, given intravenously over 10 minutes, followed by a another IV treatment of 0.08 mEq/kg per hour for 24 hours. Magnesium levels were measured 30 minutes and 24 hours after therapy began.
Compared to placebo, IV magnesium reduced heart rhythym abnormalities per hour by about 50%. It also reduced episodes of ventricular tachycardia per day by about 65%. Intravenous magnesium chloride use reduces the frequency of arrhythmia in CHF patients.
Title: Effect of acute magnesium administration on the frequency of ventricular arrhythmia in patients with heart failure.
Author: Sueta CA, Clarke SW, Dunlap SH, Jensen L, Blauwet MB, Koch G, Patterson JH, Adams KF Jr
Source: Circulation 1994 Feb;89(2):660-666
PMID: 7508827, UI: 94147599
IV Magnesium and Angina
January 5, 2001 - In patients with angina caused by blood vessel spasms, IV magnesium expands the coronary arteries and reduces those spasm, according to a new report.
In 22 patients with vasospastic angina, Dr. Hiroki Teragawa caused such spasms with acetylcholine. In 14 patients - after the spasm had spontaneously stopped - researchers gave IV magnesium sulfate at 0.27 mmol/kg of body weight over 20 minutes. As a control, the other 8 patients received IV placebo (isotonic glucose).
Dr. Teragawa then induced another coronary spasm in the patients and measured the diameter of their coronary arteries. Magnesium dilated the entire coronary artery. During spasm, the severity of chest pain and EKG abnormalities were reduced in the magnesium group. The diameter of the spastic arteries improved from an aveage -63% to -44% during coronary spasm in the patients taking magnesium. Overall, 71% of the magnesium patients responded favorably.
Among control patients during coronary spasm, there were no changes in severity of chest pain, EKG abnormalities, or diameter of the coronary arteries. "These findings suggest that IV magnesium may have a therapeutic use in patients with ischemic heart disease associated with coronary spasm. Long-term oral magnesium supplements might prevent or reduce coronary spasm in patients with this type of angina," Dr. Teragawa concluded.
Source: Chest 2000;118:1690-1695
IV Magnesium and A-fib
January 31, 2001 - Risk of atrial fibrillation - a common complication of CABG - is reduced when magnesium is given.
Dr. Huseyin Alhan studied magnesium's ability to prevent a-fib after bypass surgery. He gave 200 patients having bypass either 1.5 grams of IV magnesium or just a saline solution alone; one day before, during, and 4 days after surgery.
Only 2% of magnesium-treated patients had a-fib after surgery, while 21% of untreated patients had a-fib. "Many studies have shown that magnesium has an effect on a-fib, but the proper dose and when to give it remained unclear," Dr. Alhan said. "We give this therapy to patients with normal as well as low magnesium levels," he stated.
"In the elderly it has been shown that patients may be completely deficient in magnesium but still test normal on blood tests," Dr. Alhan explained. "We are not sure if the benefit is from replenishing a deficiency or if it is just an effect of magnesium."
"Atrial fibrillation is not the most serious complication after heart 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 of heart surgery. The patients who received magnesium in this study went home earlier."
From: The 37th annual meeting of The Society of Thoracic Surgeons
Source: Reuters Health
Electrolyte Levels and CHF
1994 - Thiazides and loop diuretics cause potassium and magnesium loss through the kidneys, which leads to deficiencies that require supplements. These losses may be overlooked because blood levels of both electrolytes may remain normal even when the muscle concentrations are far too low.
We tested 76 patients who had taken diuretics for 1 to 17 years. The average levels K (potasium), MG (magnesium) and niacin "pumps" in skeletal muscle biopsies were greatly lower in these patients than in the biopsies from a healthy control group. Magnesium and potassium levels were related: if one was low, the other was low.
The blood levels though, were only low in a few patients. The fact that MG and K deficiencies are often overlooked shows the need for checking skeletal muscle. A simple biopsy needle procedure detects electrolyte problems even if blood levels seem okay. With this technique we detected build-up of the muscle electrolytes after a MG supplementation period. Oral magnesium supplements can re-establish normal MG as well as potassium levels in patients on long-term diuretic therapy, provided that supplements are taken for 6 months. Restoring muscle MG and K was linked to a restored Niacin level.
Title: Magnesium and potassium deficiency. Its diagnosis, occurrence and treatment in diuretic therapy and its consequences for growth, protein synthesis and growth factors
Author: Dorup I
Source: Acta Physiol Scand Suppl 1994;618:1-55
PMID: 8036903, UI: 94310918
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another brief artice at:
http://www.mothernature.com/Library/bookshelf/Books/10/7.cfm
