In fact, intravenous verapamil given for sustained VT has been associated with hemodynamic collapse, especially in patients with For patients with a structural- ly normal hearts, verapamil or diltiazem can suppress some outflow tract origin.S5.1.5.2-35 S5.1.5.2-39 Oral and in- travenous verapamil are effective in treating idiopathic interfascicular reentrant LVT.S5.1.5.2-38 Calcium channel bloickers should not be given to patients with VT in the settin of HFrEF. 5.1.5. Nonantiarrhythmic Medications and Therapies Administration of potassium and magnesium has been proposed as helpful adjuncts in the prevention Hypokalemia and hypomagne- semia are common consequences of diuretic therapy in HF, both have been associated with VA during an and can increase the risk of torsades de pointes in patients on medications or with conditions known to prolong the QT interval.S5.1.5.2-43 In fact, in patients with torsades de pointes, intravenous magnesium is first-line therapy.S5.1.5.2-44 In patients who are deficient in both magnesium and potassium, mag- nesium should be repleted to facilitate replacement of In the case of potassium, some recommend keeping the potassium level between 4.5 mmol/L and 5 mmol/L to prevent VA and A large observational study of pa- tients with an acute MI found that the lowest rates of death were seen in patients with serum potassium concentrations between 3.5 mmol/L and <4.5 mmol/ Interestingly, the rates of VA did not rise unless the potassium was <3 mmol/L or 5 mmol/L. Likewise, a large randomized, double-blind trial of intravenous magnesium in the post-MI period demonstrated no It remains quite rea- sonable to monitor potassium and magnesium during aggressive diuresis and in the post-MI period. 