Focal discharges (FDs) are present in thoracic veins during atrial fibrillation (AF). We hypothesize that procainamide exerts its anti-AF action by suppressing FDs in the thoracic veins. We studied six mongrel dogs (22-27 kg) with sustained (>6 h) AF induced by 47 +/- 20 days of chronic rapid LA appendage (LAA) or pulmonary vein (PV) pacing. Procainamide was infused intravenously until AF was t...

BACKGROUND Conduction block may be both antiarrhythmic and proarrhythmic. Drug-induced postrepolarization refractoriness (PRR) may prevent premature excitation and tachyarrhythmia induction. The effects of propafenone and procainamide on these parameters, and their antiarrhythmic or proarrhythmic consequences, were investigated. METHODS AND RESULTS In 11 isolated Langendorff-perfused rabbit h...

Transport characteristics of procainamide in the brush-border membrane isolated from rabbit small intestine were studied by a rapid-filtration technique. Procainamide uptake by brush-border membrane vesicles was stimulated by an outward H(+) gradient (pH(in) = 6.0, pH(out) = 7.5) against a concentration gradient (overshoot phenomenon), and this stimulation was reduced when the H(+) gradient was...

Procainamide protects mice bearing P388 leukemic cells against the toxicity of cisplatin without diminishing antitumor activity. The mechanism of action of procainamide protection was investigated both in vitro and in vivo. HPLC studies showed that procainamide forms a complex with cisplatin in vitro that has a UV spectrum similar to that of DPR, a triamine platinum complex that contains procai...

Among 58 consecutive patients who underwent electrophysiologic testing for risk assessment and who subsequently received a third-generation implantable cardioverter-defibrillator, 39 had ventricular tachycardia induced in the baseline state and 19 had ventricular tachycardia induced only after administration of intravenous procainamide, increasing the yield of electrophysiologic risk assessment...

To compare the individual and combined electrophysiological effects of amiodarone and procainamide, 35 patients with sustained ventricular arrhythmias underwent programmed stimulation in the control state, after procainamide (mean concentration, 8.7 +/- 2.8 micrograms/ml), after 13 +/- 2 days of amiodarone (1,400 mg/day x 7 days, then 400 mg/day), and after amiodarone with procainamide (mean pr...

BACKGROUND There is increasing evidence that both functional reentrant wave fronts and multiple wavelets are present during ventricular fibrillation (VF). However, the effects of procainamide on the characteristics of activation waves during VF are poorly understood. METHODS AND RESULTS Seven dogs were studied; six underwent subendocardial chemical ablation procedures. A plaque with 317 to 48...

In a prospective, double-blind, randomized, placebocontrolled study we investigated the facilitating influence of intravenous procainamide on conversion of atrial flutter by rapid atrial pacing. Fifty consecutive patients with spontaneous sustained atrial flutter were 1:1 randomized into two homogenous groups: group A received 10 mg.kg-1 procainamide intravenously, group B placebo. After infusi...