Oral magnesium therapy, exercise heart rate, exercise tolerance, and myocardial function in coronary artery disease patients.
BACKGROUND
Previous studies have demonstrated that in patients with coronary artery disease (CAD) upward deflection of the heart rate (HR) performance curve can be observed and that this upward deflection and the degree of the deflection are correlated with a diminished stress dependent left ventricular function. Magnesium supplementation improves endothelial function, exercise tolerance, and exercise induced chest pain in patients with CAD.


OBJECTIVE
We studied the effects of oral magnesium therapy on exercise dependent HR as related to exercise tolerance and resting myocardial function in patients with CAD.


METHODS
In a double blind controlled trial, 53 male patients with stable CAD were randomised to either oral magnesium 15 mmol twice daily (n = 28, age 61+/-9 years, height 171+/-7 cm, body weight 79+/-10 kg, previous myocardial infarction, n = 7) or placebo (n = 25, age 58+/-10 years, height 172+/-6 cm, body weight 79+/-10 kg, previous myocardial infarction, n = 6) for 6 months. Maximal oxygen uptake (VO2max), the degree and direction of the deflection of the HR performance curve described as factor k<0 (upward deflection), and the left ventricular ejection fraction (LVEF) were the outcomes measured.


RESULTS
Magnesium therapy for 6 months significantly increased intracellular magnesium levels (32.7+/-2.5 v 35.6+/-2.1 mEq/l, p<0.001) compared to placebo (33.1+/-3.1.9 v 33.8+/-2.0 mEq/l, NS), VO2max (28.3+/-6.2 v 30.6+/-7.1 ml/kg/min, p<0.001; 29.3+/-5.4 v 29.6+/-5.2 ml/kg/min, NS), factor k (-0.298+/-0.242 v -0.208+/-0.260, p<0.05; -0.269+/-0.336 v -0.272+/-0.335, NS), and LVEF (58+/-11 v 67+/-10%, p<0.001; 55+/-11 v 54+/-12%, NS).


CONCLUSIONS
The present study supports the intake of oral magnesium and its favourable effects on exercise tolerance and left ventricular function during rest and exercise in stable CAD patients.
Pokan
R
R
Department of Sport and Exercise Physiology, University of Vienna, Vienna, Austria.
Hofmann
P
P
von Duvillard
S P
SP
Smekal
G
G
Wonisch
M
M
Lettner
K
K
Schmid
P
P
Shechter
M
M
Silver
B
B
Bachl
N
N
D000284:Administration, Oral; D000368:Aged; D003324:Coronary Artery Disease / Q000188:drug therapy* / Q000503:physiopathology; D019587:Dietary Supplements; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008274:Magnesium / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D011446:Prospective Studies; D016277:Ventricular Function, Left / Q000187:drug effects
D008274:Magnesium