[Magnesium sulfate in acute myocardial infarction]. / Il solfato di magnesio nell'infarto miocardico acuto.

Magnesium sulphate has antiarrhythmic and antithrombotic properties, a coronary and systemic vasodilating action, a direct myocardial protective effect in experimental and clinical models of ischemia-reperfusion injury. Two meta-analyses have pooled the results of several small studies that had analyzed the effect of controlled hypermagnesiemia in acute myocardial infarction before the advent of thrombolytic and antithrombotic therapies. The results have shown a more than 50% mortality reduction, with a minimum estimated benefit of about 30%, and a reduction in ventricular arrhythmias of about 50%. In LIMIT-2, a double-blind trial of 2,316 patients where magnesium was administered as a 8 mMol bolus followed by a 24-hour infusion of 65 mMol, a 24% reduction in mortality was observed. However, these data have not been confirmed in the more than 58,000 patients of the ISIS-4 trial. In this study magnesium, at the same dose of the LIMIT trial, did not reduce 5-week mortality, neither in the general population (7.64% versus 7.24% in control patients, p = n.s.) nor in specific subgroups. The results of ISIS-4 have excluded the routine use of magnesium sulphate in acute myocardial infarction in the era of fibrinolysis and aspirin, beta-blockers and ACE-inhibitors. Nevertheless, magnesium administration could still be considered in certain clinical situations, such as 1) the presence of contraindications to fibrinolysis and aspirin, 2) the treatment of ventricular tachyarrhythmias unresponsive (or as an alternative) to lidocaine, 3) severe hypertension when beta-blockers are not indicated.

[Multicenter study of the effectiveness and tolerance of clotiazepam in cardiology]. / Studio policentrico sull'efficacia e tollerabilità del clotiazepam in cardiologia.

In a phase IV study with clotiazepam 9 cardiologists were involved to treat 86 patients (52 female, 32 male, mean age 51 years) effected by cardiovascular diseases and anxiety. The dosage was 5-10 mg TID, and the treatment lasted for 3 weeks. Variations of the dosage were requested in 21% of patients and generally at the 2nd week of treatment. The safety of clotiazepam was good: only in the 14% of patients side-effects were observed (especially drowsiness 9.3% and asthenia 2.3%). Clotiazepam was judged to be effective in 75% of patients. The Hamilton psychiatric rating scale for anxiety showed a progressive decrease both of the total score and of the scores of every item; the cardiovascular symptoms particularly improved at both the controls.

Efficacy of mexiletine in chronic ventricular arrhythmias: a multicentre double-blind medium-term trial.

In a multicentre double-blind, inpatient, placebo-controlled trial the effects on premature ventricular beats (PVBs) of mexiletine in a standard, submaximal dose were studied by Holter monitoring in 144 outpatients. After wash-out, mexiletine was administered for 14 days. The effects were re-tested, after one week of a placebo, in a second 14-day period of mexiletine administration. Of the patients 73% in the first period and 82.5% in the second period responded to mexiletine (a reduction of 75% or more of PVBs/24 h--p less than 0.001 compared with the placebo for both periods). Mexiletine also significantly reduced the Lown class of PVBs and the frequence of paired PBVs, ventricular tachycardia, multiform beats and R on T wave phenomenon. Mexiletine showed an equivalent effectiveness in the four main aetiological groups of arrhythmias. Fifty nine patients complained of adverse effects (gastrointestinal or neurological) the intensity of which led to the stopping of the treatment in 16 of them. These results show that mexiletine is highly effective, even in submaximal doses, in preventing ventricular arrhythmias of whatever origin.