[Clinical effects of magnesium sulfate in the treatment of supraventricular tachyarrhythmia].

The obvious effects of magnesium sulfate are noticed not only in ventricular tachyarrhythmia but also in supraventricular tachyarrhythmia (SVTA) which include paroxysmal supraventricular tachycardia (PSVT), chaotic atrial tachycardia (CAT), atrial fibrillation (AF) with rapid heart rate and nonparoxysmal junctional tachycardia (NPJT). This paper reports the effects of magnesium sulfate treatment in 25 cases of SVTA in a self-controlled before and after study. Among 10 cases of PSVT, 6 cases were treated by injection of 25% magnesium sulfate 5-10 ml. Except 2 cases with W-P-W and aberrant ventricular condition, the PS-VT were terminated immediately after half a dose of magnesium sulfate i.v. in 2 cases, other 2 cases were terminated by 5-10 min after a dose of magnesium sulfate i.v.. Some improvements were observed in these 4 cases. The rest 4 cases were prevented by 12 days' intravenous infusion of 1% magnesium sulfate 250 ml per day, 3 cases of them recovered. Three cases of CAT recovered within an hour to two days by infusion of 1% magnesium sulfate 250 ml. Four cases of AF with rapid heart rate were collected, even though it is difficult to determine whether it is due to overdose or inadequacy of digitalis. The heart rates were reduced by magnesium sulfate injection in those 4 cases. Eight cases of NPJT due to heart failure with digitalis intoxication recovered after infusion of 1% magnesium sulfate 250ml within 10 hours to two days. Finally, the mechanism of the effect of magnesium sulfate treatment in SVTA was discussed.