Acute Hypokalemia May Not Be an Effective Way to Sensitize the In Situ Canine Heart for Sparfloxacin-Induced Long QT Syndrome

Extents of the sparfloxacin (3 – 10 mg/kg, i.v.)-induced QT interval prolongation under normokalemic and hypokalemic conditions were assessed in halothane-anesthetized beagle dogs (n = 5). The hypokalemic condition was induced by an oral administration of furosemide (200 mg/kg per day) for 3 days, which decreased the serum potassium concentration from 3.65 ± 0.13 to 2.35 ± 0.13 mM (P