Page 19 - ADD-ON ABLATION SURGERY IN PATIENTS WITH ATRIAL FIBRILLATION

According to the current guidelines amiodarone, dronedarone, flecainide,
propafenone and I-sotalol are recommended for rhythm control86. In selected 1 highly symptomatic patients with occasional recurrences of AF (i.e. between once
per month and once per year), the ‘pill-in-the-pocket’ approach consisting of oral
propafenone (450–600 mg) or flecainide (200–300 mg) may be used92. Drugs
commonly used for rate control are ß-blockers, non-dihydropyridine calcium
channel antagonists and digitalis.Amiodarone may be suitable for some patients
with otherwise refractory rate control86.
Antiarrhythmic drugs have low therapeutic indices and limited long-term
efficacy93 and attainment and maintenance of sinus rhythm have been suboptimal
in comparative studies such as AFFIRM94, HOT CAFÈ95, PIAF96, RACE97, STAF98
and AF-CHF99.
RACE and AFFIRM have shown an almost significant trend towards reduced
mortality and stroke by rate control, but this may have been due to inadequate anticoagulation among patients in whom AF seemed to be controlled with antiarrhythmic drugs94,97. Two drawbacks for treatment with antiarrhythmic
drugs in the maintenance of SR are inconsistent efficacy and severe side effects. Furthermore, SR is difficult to obtain. In RACE and AFFIRM only 30-50% of
patients were in SR at the end of follow-up. As a large group of patients show
severe and frequent symptoms of AF (despite the use of many antiarrhythmia
and rate control drugs) while being at great risk or systemic embolization, non- pharmacological approaches in the treatment of AF have gained increased interest
over the last few years.
Vernakalant is a is a relatively atrial-selective antiarrhythmic agent100 recently recommended for approval by the European Medicines Agency for rapid cardioversion of recent-onset AF to sinus rhythm in adults (≤7 days for non-
surgical patients;≤3 days for surgical patients)101,102.Atrial-selectivity ofVernakalant
is achieved by targeting atrial specific channels: the Kv1.5 channel which carries
K+ current (IKur) and the Kir3.1/3.4 channel which carries muscarinic K+ current (IKAch).Vernakalant can also work to block Ito, late Ina, with minor blockade of
IKr currents.
A direct comparison with amiodarone in theAVRO trial103 showed thatVernakalant
was more effective than amiodarone for the rapid conversion of AF to SR.
Rate reduction, allowing adequate time for ventricular filling and avoiding rate-
related ischemia, may result in improved haemodynamics.92 However, the RACE
II study shows that lenient-rate control < 110 bpm is not inferior to strict-
Introduction
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