The results of ISIS-4 seemed to contradict the results of the above studies. A total of 58,043 patients were enrolled in ISIS-4, 29,009 allocated to magnesium and 29,034 to control. There were 2,196 deaths (7.6 percent) by 35 days in the magnesium group and 2,079 deaths (7.2 percent) in the control group (OR 1.06[0.99-1.13]) suggesting no mortality benefit of magnesium administration and even the possibility of slight harm. The findings of ISIS-4 have triggered considerable controversy over the reasons why it produced a null effect for magnesium in reducing mortality in suspected acute MI.