Cervical cytology screening

data show that the most striking improvement was a reduction in deaths from cardiogenic shock. This may well have occurred because of poor matching of the placebo and treatment groups. The treatment group were younger and had a lower prevalence of previous ischaemic heart disease than the placebo group. The idea that intravenous magnesium could be beneficial by causing coronary vasodilatation is interesting, but to our knowledge there are no trials in vivo comparing the use of magnesium with intravenous nitrates. DAVID P LIPKIN COLIN J REID