OBJECTIVES The purpose of this study was to determine whether verapamil has rate-dependent effects on the atrial effective refractory period (AERP). BACKGROUND Block of calcium current (I(Ca)) and rapid component of the delayed rectifier potassium current (I(Kr)) by verapamil is frequency-dependent. This may result in variable effects of verapamil on the AERP, depending on the rate. METHODS...

PURPOSE Verapamil, a voltage-gated calcium channel blocker, has been occasionally reported to have some effect on reducing seizure frequency in drug-resistant epilepsy or status epilepticus. We aimed to investigate the efficacy of verapamil as add-on treatment in children with drug-resistant epilepsy. METHODS Seven children with drug-resistant structural-metabolic, unknown or genetic (e.g., D...

Mitochondria are morphologically dynamic organelles which undergo fission and fusion processes. Our previous study found that arterial constriction was always accompanied by increased mitochondrial fission in smooth muscle cells, whereas inhibition of mitochondrial fission in smooth muscle cells was associated with arterial relaxation. Here, we used the typical vasorelaxants, verapamil and phen...

Transmembrane electrical activity was recorded from endocardium and epicardium of isolated segments of guinea pig right ventricular free walls. An electrocardiogram was recorded by electrodes at opposite ends of the tissue bath. Endocardium was stimulated. Tissues were exposed to "ischemic" conditions (e.g., acidosis, hyperkalemia, hypoxia, and lactate) for 15 minutes and then were reperfused w...

* 511(12 Reversal Mechanism of Multidrug Resistance by Verapamil: Di rect Binding of Verapamil to P-Glycoprotein on Specific:Sites and Transport of Verapamil Outward across the Plasma Membrane of K562/ADM Cells. Keisuke Yusa and Takashi Tsuruo. 5007 Lysis of Antigenically Unrelated Tumor Cells Mediated by Lyt 2* Splenic T-Cells from Melphalan-cured MOPC-315 Tumor Bear ers. Edward Barker,James A...

Objective: To evaluate the role of calcium channel blockers and their mechanisms of action on acute inflammation of rat paw. Material and Methods: The study was conducted using carrageenan-induced rat paw inflammation model. Two different doses of nifedipine and verapamil (25 and 400 μg/kg, i.p.) were used. Edema was assessed by calculating the volume changes and by extravasation of Evans blue ...

A controlled double-blind study of verapamil in 16 anginal patients used two dose levels-40 mg. t.d.s. and 120 mg. t.d.s.-and was compared with propranolol 100 mg. t.d.s. At the higher dosage verapamil produced a significant improvement in frequency of angina, trinitrin consumption, and exercise tolerance, and had a favourable and significant effect on the amount and duration of ischaemic S-T d...

The efficacy, electrophysiologic effects, and side effects of adenosine triphosphate (ATP) and verapamil in the short-term management of paroxysmal reciprocating junctional tachycardia (PRJT) were compared in 20 patients. All patients had inducible sustained PRJT during control electrophysiologic study. Fourteen patients had PRJT involving a retrograde accessory pathway, and six patients had at...

Despite current advancements in pharmacologic and nonpharmacologic therapy, many patients with persistent atrial Ž brillation (AF) continue to be managed with periodic external electrical cardioversion. During 1997, 89,000 inpatients in the United States underwent electrical cardioversion for AF.1 Unfortunately, successful restoration of sinus rhythm often is followed by recurrent AF, with most...