Cardiac Electrophysiology And Heart Failure Practice Test

Dofetilide carries a real risk of QT interval prolongation and torsades de pointes because it is a pure IKr blocker with a narrow therapeutic window. To safely start this drug, initiation must occur in a hospital setting where continuous ECG monitoring is available and dosing can be adjusted based on renal function. Before starting, baseline QTc and renal function (creatinine clearance) are assessed, and the dose is tailored to the patient’s kidney function. During initiation, QTc is rechecked after each dose change, and if QTc prolongs beyond a safe threshold or increases significantly, doses are adjusted or held. Correcting electrolytes such as potassium and magnesium is also important to reduce proarrhythmic risk. This careful inpatient approach is essential to prevent dangerous QT prolongation during initiation, which is why inpatient monitoring of QTc and renal-adjusted dosing is required.