Temporary pacing is highly effective in managing torsades de pointes that is recurrent after potassium and magnesium supplementation.S10.7-3 Isoproterenol can also be used to increase heart rate and abolish postectopic pauses.S10.7-3 3. Intravenous magnesium can suppress episodes of torsades de pointes without necessarily shortening Repeated doses may be needed, titrated to suppress ectopy and nonsustained VT episodes while precipi- tating factors are corrected.S10.7-4 Magnesium toxicity (areflexia progressing to respiratory depression) can occur at high serum concentrations, but this risk is very small with the doses usually used to treat tors- ades de pointes, 1 to 2 g intravenously.S10.7-14 Allelic variants in clinical long QT disease genes have been identified in patients with medication- induced torsades de pointes.S10.7-7,S10.7-15 S10.7-18 Further, whole exome sequencing implicates an increased burden of rare potassium channel vari- ants in the risk of medication-induced torsades de These findings do not yet sup- port general genetic screening for prediction of medication-induced torsades de pointes. In long QT syndrome, genetic testing may be performed in the index case who experienced medication- induced torsades de pointes and, if he/she did not survive that event, electrocardiographic screening of first-degree relatives may be performed. 4. Maintaining serum potassium between 4.5 mEq/L and 5 mEq/L shortens QT and may reduce the chance of recurrent torsades de pointes.S10.7-6,S10.7-7 5. 