[Effectiveness of combined use of verapamil and adenosine triphosphate in experimental animals]. / Effektivnost' kombinirovannogo primeneniia verapamila i adenozintrifosfata v éksperimente.

A wide application of ATP to abolish reciprocal paroxysmal tachycardia is limited by frequent and adverse effects of the drug. Experiments on 49 rats have revealed that successive intravenous injections of verapamil and ATP have a more pronounced and prolonged action than the drugs alone. It is assumed that decreased pacemaker activity of sinus nodal cells and reduced atrioventricular conduction ("binodal dysfunction") are as a result of drug calcium channel block in the cellular membranes of myocytes. Potentiation of the pharmacological action of the drugs in question may be used in the clinical setting to lower an ATP dose and to reduce the incidence of adverse effects.

[The clinical efficacy of verapamil in ventricular extrasystolic arrhythmia and parasystole]. / Klinicheskaia éffektivnost' verapamila pri zheludochkovoi ékstrasistolicheskoi aritmii i parasistolii.

An arrhythmogenic mechanism has been investigated pharmacologically by acute drug tests (ADT) and alternate block of slow calcium channels and fast sodium channels of the cellular membranes. ADT with verapamil reduced extrasystoles by 60% in 44% of patients demonstrating the predominance of calcium-dependent arrhythmogenesis. An antiarrhythmic efficacy of fast sodium channels blockers was ascertained in 33% of the patients. ADT with rhythmilen and verapamil produced a satisfactory antiarrhythmic effect in 18% of the examinees. These patients seem to have parallel activation of both fast sodium and slow calcium channels. They received courses of both drugs. It is stated that a pharmacological analysis of extrasystolic arrhythmia allows inference on pathogenesis of myocytic electrolyte disturbances which serves the basis for adequate corrective therapy.