Utility of patient-activated cardiac event recorders in the detection of cardiac arrhythmias.

Background: Patient-activated event recorders are useful for the diagnosis of arrhythmia in patients with palpitation and presyncope. However, the utility of event recorders in patients suspected of arrhythmia but presenting with other symptoms is not clear. Furthermore, the factors influencing their utility have not been evaluated.

Genistein and tyrphostin AG 556 block the action potential shortening in septic shock.

Background: We have previously shown that an increase in NO activity activated ATP-sensitive potassium channel (K(ATP)) and shortened action potential duration (APD) in an endotoxic shock model. Because the increase in NO production and the decrease of APD appear to be downstream late events in endotoxic shock, we hypothesized that a common signaling pathway might mediate these effects.

Methods: Using a guinea pig model of endotoxic shock, we investigated the effect of genistein and tyrphostin AG 556 on the cardiac action potential.

Successful use of iv diltiazem to control perioperative refractory complex atrial tachyarrhythmias in a patient with pneumoconiosis.

Purpose: To present a patient with pneumoconiosis who developed a complex, life-threatening atrial tachyarrhythmia during anesthesia. Intravenous diltiazem was effective in controlling the ventricular rate and hemodynamics after failure of other antiarrhythmic drugs and direct current cardioversion.

Clinical Features: A 79-yr-old man with pneumoconiosis complicated by cor pulmonale suffered from gout-related cellulitis of the left lower limb.

Recurrent atrial flutter and atrial fibrillation after catheter ablation of the cavotricuspid isthmus: a very long-term follow-up of 333 patients.

Introduction: Radiofrequency catheter ablation of the cavotricuspid isthmus is an effective therapy for typical atrial flutter (AFL), however, the long-term recurrence of AFL and early or late occurrence of atrial fibrillation (AF) are not well defined. This study investigated the long-term (up to 68 months) outcome of patients with typical AFL after catheter ablation of the cavotricuspid isthmus.

Methods: This study included 380 patients with typical AFL, who received linear ablation of the cavotricuspid isthmus.

Determinants of successful ablation of idiopathic ventricular tachycardias with left bundle branch block morphology from the right ventricular outflow tract.

The aim of the study was to define the factors that may predict the outcomes of radiofrequency ablation from the right ventricular outflow tract (RVOT) in patients with idiopathic VT with a QRS morphology of LBBB. Endocardial mapping and RF ablation from the RVOT were performed in 35 patients (14 men, mean age 41 +/- 14 years), and VT was successfully ablated in 30 patients. There was no significant difference with regard to clinical characteristics and electrophysiological findings between patients with successful and failed ablation.

Prolongation of cardiac repolarization by arsenic trioxide.

Arsenic trioxide (As(2)O(3); ATO) has recently been found to be very effective for relapsed acute promyelocytic leukemia. Several articles reported prolongation of QT interval or ventricular arrhythmias in patients receiving ATO. However, the QT-prolonging effect has not been confirmed and the direct membrane effect of ATO has never been studied.

Genistein inhibits the inward rectifying potassium current in guinea pig ventricular myocytes.

Genistein is an isoflavone with potent inhibitory activity on protein tyrosine kinase. Previous studies have shown that genistein has additional effects, among which the direct blocking effects on various ionic channels have recently been disclosed. Using whole-cell voltage clamp and current clamp techniques, we demonstrate that micromolar concentrations of genistein dose-dependently and reversibly inhibit the inward rectifying K(+) current, and depolarize the resting membrane potential, resulting in abnormal automaticity in guinea pig ventricular myocytes.

Effects of sildenafil on cardiac repolarization.

Objectives: Sudden death has occasionally been reported in patients taking sildenafil. The objective of this study was to investigate the effect of sildenafil on cardiac repolarization.

Methods: We used conventional microelectrode recording technique in isolated guinea pig papillary muscles and canine Purkinje fibers, whole-cell patch clamp techniques in guinea pig ventricular myocytes, and in vivo ECG measurements in guinea pigs.