Magnitude of increase in QTc interval after initiation of dofetilide in patients with persistent atrial fibrillation is associated with increased rates of pharmacological cardioversion and long-term freedom from recurrent atrial fibrillation

Pharmacologic Conversion during Dofetilide Treatment for Persistent Atrial Fibrillation

“…The study confirmed previous observations that acute dofetilide administration has a high rate of pharmacologic conversion, in about half of patients, during initiation that would spare the need for deep sedation and electrical cardioversion. The present study cohort reflects contemporary usage of dofetilide that is mainly in healthier patients than initially studied, i.e., less heart failure and LV dysfunction.…”

“…Dofetilide was well‐tolerated and had infrequent safety events. Specifically, TdP ventricular tachycardia occurred in 1.0% of treated patients, in keeping with prior experience . The vast majority, nearly 90%, of exposed patients completed the six‐dose loading phase.…”

“…This rate of conversion during the initial phase of treatment compares favorably to amiodarone, generally considered to be the most potent AAD, at a rate under 20% with significant delay until conversion . Prior studies of dofetilide were smaller than the present study of 308 patients and ranged between 43 and 223 patients, but consistently indicated a similar pharmacologic conversion rate, ranging from 42% to 63% . There was a dose response that predicted pharmacologic conversion, much higher at 500 mcg bid than 250 mcg bid.…”

“…Dofetilide has been noted to have a high rate of pharmacologic conversion during initial dosing in our and others’ prior postmarketing studies, a favorable property that would decrease patient inconvenience and simplify inpatient management. The intent of the study was to examine the safety of an inpatient loading strategy, and the incidence and patterns of pharmacologic conversion by dofetilide during the treatment of persistent AF in a large contemporary consecutive cohort.…”

“…Specifically, TdP ventricular tachycardia occurred in 1.0% of treated patients, in keeping with prior experience. [6][7][8][9][10][11] The vast majority, nearly 90%, of exposed patients completed the six-dose loading phase. The most common reason for failure to discharge home on medication was excessive QTc prolongation, an observation that supports close monitoring of ECG in an inpatient unit.…”