Vernakalant demonstrated efficacy superior to amiodarone for acute conversion of recent-onset AF. Both vernakalant and amiodarone were safe and well tolerated in this study. (A Phase III Superiority Study of Vernakalant vs Amiodarone in Subjects With Recent Onset Atrial Fibrillation [AVRO]; NCT00668759).

These data suggest that RSD1235's clinical selectivity and AF conversion efficacy result from block of potassium channels combined with frequency- and voltage-dependent block of INa.

RSD1235, a new atrial-selective anti-arrhythmic agent, appears to be efficacious and safe for converting recent onset AF to sinus rhythm.

At doses similar to those tested clinically, vernakalant dose-dependently prolonged atrial refractoriness, prolonged AV nodal conduction and refractoriness, and slightly prolonged QRS duration, but it had no effect on ventricular refractoriness.

1Rats were used to evaluate the antiarrhythmic properties of tedisamil, a novel agent with the electrophysiological properties of a Class III antiarrhythmic drug. Tedisamil was tested against coronary artery occlusion-induced arrhythmias in conscious animals. 2 The actions of tedisamil on the ECG, as well as responses to electrical stimulation, were compared with those on the configuration of epicardial intracellular action potentials recorded in vivo. 3 Tedisamil (1-4mgkg-1, i.v.) caused bradycardia, elevated blood pressure and dose-dependently reduced ventricular fibrillation (VF) induced by occlusion of the left anterior descending coronary artery. Other ischaemia-associated arrhythmias were not so well suppressed. Antiarrhythmic activity was greatest when the tedisamil-induced bradycardia was prevented by electrically-pacing the left ventricle. 4 Tedisamil dose-dependently lengthened the effective refractory period and prevented electricallyinduced VF. In vivo, i.v.) prolonged the duration of epicardial intracellular action potentials by up to 400%. 5 Results showed that tedisamil possessed antifibrillatory actions in rats that were related to Class III electrophysiological actions as revealed by electrical stimulation and electrophysiological analyses.