Bemarinone (ORF 16600) is a positive inotropic and vasodilator agent with potential clinical utility in the management of congestive heart failure. The compound selectively and competitively inhibited cyclic AMP phosphodiesterase fraction III. However, further studies were discontinued

ITROCAINIDE is an antiarrhythmic agent.

LEDAZEROL is a derivative of mivazerol. It was under development as an antianginal agent.

Butoprozine increased the action potential duration like amiodarone, depressed the plateau phase like verapamil and decreased the amplitude and the maximum rate of depolarization. Butoprozine injected intravenously depressed sino-atrial node function, lengthened A-V nodal conduction time and the A-V nodal refractory period, and prolonged the atrial refractory period. Thus butoprozine acted preferentially on parts of the myocardial tissue where the slow inward current seems to be particularly involved. In this respect, butoprozine was more active than amiodarone, but in contrast to this drug, butoprozine did neither prolong the ventricular monophasic action potential duration nor the ventricular refractory period.

Budiodarone is a chemical analog of amiodarone with mixed ion channel electrophysiological activity. Budiodarone was developed to capitalize on the proven efficacy of amiodarone and to avoid its side effects. Budiodarone has a short plasma half-life (7 h) and a lower volume of distribution (13 L/kg). It is cleared from the body in 48 h. Like amiodarone, Budiodarone has balanced, multiple cardiac ion channel inhibiting activity, giving it properties of all four Vaughan Williams antiarrhythmic drug classes. Budiodarone, unlike amiodarone, undergoes rapid metabolism by plasma and tissue esterases. In clinical trials, Budiodarone effectively reduces the number and duration of atrial tachycardia/atrial fibrillation episodes.

Edifolone (SC-35135) is a structurally unique class Ia antiarrhythmic agent. It acts as a sodium channel antagonist. Edifolone development has been discontinued.

Altapizone is a platelet aggregation inhibitor. It is a vasodilator.

Bisaramil, an antiarrhythmic drug was developed as an inhibitor of calcium transport and as a membrane stabilizer. In addition, the drug showed tonic and frequency-dependent block that is most potent against the heart Na+ channel. However, the phase-II for Arrhythmias in Japan was discontinued.

Astra Hässle (now Hässle Läkemedel, a subsidiary of AstraZeneca) of Sweden was developing an IV formulation of almokalant for use in the treatment of atrial arrhythmias. Almokalant is a selective blocker of the delayed outward K+ current. Almokalant exhibited properties of a selective class III antiarrhythmic agent, devoid of β-blocking activity, in vitro and in vivo, in animals and humans. In humans, prolongation of the refractoriness of the atria and ventricles has been demonstrated, as well as a prolongation of the ventricular repolarization. A moderate antiarrhythmic efficacy has been disclosed in studies in patients with supraventricular reciprocating tachycardias, with atrial fibrillation and with premature ventricular contractions. Almokalant also has proarrhythmic potential and thedevelopment of almokalant was discontinued due to induction of Torsade de Pointes, which occurred in some susceptible patients during the clinical trials.

Biclodil was investigated as an antihypertensive vasodilator.