Vagal activity modulates spontaneous augmentation of J-wave elevation in patients with idiopathic ventricular fibrillation.

Background: Although J-wave elevation in the inferolateral leads could be related to idiopathic ventricular fibrillation (IVF), little is known about the pathophysiologic characteristics of J-wave elevation in patients with IVF.

Objective: This study aimed to determine the relationship between augmentation of J-wave elevation and changes in RR interval or autonomic nervous activities in patients with IVF.

Methods: Eight patients with IVF and 22 controls with J-wave elevation (≥0.

Angiotensin II type 1 receptor blocker attenuates diabetes-induced atrial structural remodeling.

Background: Diabetes mellitus promotes atrial structural remodeling, thereby producing atrial arrhythmogenicity, where advanced glycation endproducts (AGEs) and their receptor (RAGE) are implicated to play a role in the pathogenesis.

Purpose: We investigated the effects of candesartan, an angiotensin type II receptor blocker, on the diabetes-induced atrial structural change.

Methods And Results: Diabetes was induced in 8-week-old female Sprague-Dawley rats by intraperitoneal injection of streptozotocin at 70 mg/kg.

Early repolarization in Wolff-Parkinson-White syndrome: prevalence and clinical significance.

Aims: Idiopathic ventricular fibrillation (IVF) with early repolarization (ER) has recently been reported; however, ER is a common finding in healthy subjects and is also found sporadically in patients with Wolff-Parkinson-White (WPW) syndrome. The present study was designed to evaluate the prevalence and clinical significance of ER in patients with WPW syndrome.

Methods And Results: One hundred and eleven patients with WPW syndrome were studied retrospectively.

Deficiency of testosterone associates with the substrate of atrial fibrillation in the rat model.

Background: Since the prevalence of atrial fibrillation (AF) increases progressively with aging, especially in men, we hypothesized that testosterone might affect the occurrence of AF.

Methods And Results: We examined the electrophysiological properties of the atria in isolated-perfused hearts of sham-operated male (SM), female (SF), orchiectomized male with and without administration of testosterone (ORCH-T and ORCH), and ovariectomized female (OVX) Sprague-Dawley rats. An electrophysiological study revealed that repetitive atrial responses induced by electrical stimuli significantly increased in ORCH rats without changes in other electrophysiological properties and were abolished by administration of testosterone.

Junctional rhythm associated with ventriculoatrial block during slow pathway ablation in atypical atrioventricular nodal re-entrant tachycardia.

Aims: We assessed responses to slow pathway ablation with respect to the appearance of ventriculoatrial (VA) block during junctional rhythm in both typical and atypical types of atrioventricular nodal re-entrant tachycardia (AVNRT).

Methods And Results: The 31 subjects included 16 patients with slow-fast type of typical AVNRT and 15 patients with atypical AVNRT (9 patients with fast-slow type and 6 patients with slow-slow type). During atypical AVNRT, the HA interval was prolonged (>70 ms) and the earliest atrial activation was located around the coronary sinus (CS) ostium.

AGEs-RAGE system mediates atrial structural remodeling in the diabetic rat.

Background: Diabetes mellitus (DM) is one of the independent risk factors for atrial fibrillation (AF). Our previous study has indicated that DM causes atrial structural remodeling with intraatrial conduction disturbances. We tested the hypothesis that the advanced glycation end products (AGEs) and the receptor for AGE (RAGE), which have been implicated in diabetic complications, are responsible for the atrial structural remodeling.

Angiotensin type 1 receptor blockade prevents endocardial dysfunction of rapidly paced atria in rats.

Introduction: Atrial fibrillation (AF) per se causes atrial endocardial dysfunction leading to local coagulation imbalance on the internal surface of the atrium, which contributes to thrombus formation in the fibrillating left atrium.

Materials And Methods: To test a hypothesis that blockade of angiotensin II type 1 receptor (AT1-receptor) prevents the endocardial dysfunction by AF, we examined the effects of olmesartan on the expression of tissue factor pathway inhibitor (TFPI), thrombomodulin (TM), endothelial nitric oxide synthase (eNOS) and plasminogen activator inhibitor-1 (PAI-1) in the endocardium of the rapidly paced rat atria.

Results: Rapid pacing induced a significant decrease in TFPI, TM and eNOS and an increase in PAI-1 protein in the left atrium.

Postprandial augmentation of bradycardia-dependent ST elevation in patients with Brugada syndrome.

Introduction: In patients with Brugada syndrome, the circadian variation of ST elevation could be modulated by the autonomic nervous activity and RR interval. Recently, glucose-induced insulin secretion was also reported to contribute to fluctuation of ST elevation. Therefore, we assessed the effects of taking meals on the ST-RR relationship in the daily life of patients with Brugada syndrome.

Rate control and quality of life in patients with permanent atrial fibrillation: the Quality of Life and Atrial Fibrillation (QOLAF) Study.

Background: The present study aimed to determine whether quality of life (QOL) in permanent atrial fibrillation (AF) patients would be improved by monotherapy with beta-blocker (BB) or calcium antagonist (CAA) as compared with digitalis.

Methods And Results: Twenty-nine patients with permanent AF under digitalis were randomized into BB (bisoprolol, atenolol or metoprolol) or CAA (verapamil) monotherapy treatment group. Twenty-five were men and the mean age was 67+/-8 years.

Bradycardia-dependent ECG changes in Brugada syndrome.

Background: In patients with Brugada syndrome (BS), ventricular fibrillation (VF) occurs mainly during sleep; therefore, not only vagal activity but also bradycardia dependent changes in ECG may relate to the nighttime occurrence of VF. The present study aimed to examine the difference in bradycardia-dependent changes in the ECG of symptomatic and asymptomatic BS patients.

Methods And Results: Twenty-one patients with BS were categorized into symptomatic (n = 9) and asymptomatic (n = 12) groups.

Enalapril preserves sinus node function in a canine atrial fibrillation model induced by rapid atrial pacing.

Methods And Results: Seventeen beagles were pretreated with either placebo (group I, n = 9) or enalapril 1 mg/kg/day (group II, n = 8) and paced at 500/min from the right atrial appendage for 4 weeks. Every week, corrected sinus node recovery time (CSNRT) and sinus cycle length (SCL) were measured. Quantitative analysis of interstitial fibrosis (IF) and adipose tissue (AT) in the SN was performed with Masson's trichrome stain, and apoptosis of the sinus nodal cells were detected with terminal deoxynucleotidyl transferase nick end-labeling.

Repolarization dynamics in patients with idiopathic ventricular fibrillation: pharmacological therapy with bepridil and disopyramide.

The electrocardiographic parameters relating occurrence of ventricular fibrillation (VF) episodes in patients with idiopathic VF (IVF) are still unknown. The aim of this study was to clarify efficacy of pharmacological therapy in patients with IVF with respect to repolarization dynamics. The study group consisted of 8 men (age 43.

Dynamic changes in the QT-R-R relationship during head-up tilt test in patients with vasovagal syncope.

Background: QT interval is influenced by preceding R-R intervals and autonomic nervous tone. Changes in QT intervals during vasovagal reflex might reflect autonomic modulation of ventricular repolarization; however, this issue has not been fully elucidated. This study aimed to evaluate dynamic response of QT interval to transient changes in R-R interval during vasovagal syncope (VVS) induced by head-up tilt test.

Drug-induced changes in fibrillation cycle length and organization index can predict chemical cardioversion of long-lasting atrial fibrillation with bepridil alone or in combination with aprindine.

Background: The aim of this study was to investigate whether drug-induced changes in fibrillation wave characteristics can predict pharmacological conversion of long lasting persistent atrial fibrillation (AF).

Methods And Results: The study group comprised 23 consecutive patients with AF lasting > or =1 month. Patients first received bepridil (200 mg/day) for 2-4 weeks.

Canine model of Brugada syndrome using regional epicardial cooling of the right ventricular outflow tract.

Introduction: Myocardial cooling can induce J point elevation (Osborn wave) as seen on ECG of the Brugada syndrome by activating transient outward current (Ito) and causing a spike-and-dome configuration of the monophasic action potential (MAP) in the ventricular epicardium in isolated canine ventricular wedge preparations. We determined the effect of regional epicardial cooling of the right ventricular outflow tract (RVOT) on surface ECG and ventricular vulnerability in the dog.

Methods And Results: In 12 dogs, a cooling device (20-mm diameter) was attached to the RVOT epicardium, and surface ECG, epicardial MAP, and endocardial MAP were recorded.

Maintenance of sinus rhythm and recovery of atrial mechanical function after cardioversion with bepridil or in combination with aprindine in long-lasting persistent atrial fibrillation.

Background: The aim of this study was to evaluate pharmacological cardioversion of long-lasting persistent atrial fibrillation (AF) using bepridil in terms of recovery of atrial mechanical function and maintenance of sinus rhythm. Bepridil alone or in combination with aprindine is effective for termination of persistent AF.

Methods And Results: The study group comprised 38 consecutive patients (24 men, 58.

Entrainment mapping of dual-loop macroreentry in common atrial flutter: new insights into the atrial flutter circuit.

Introduction: The aim of this study was to determine using entrainment mapping whether the reentrant circuit of common type atrial flutter (AFL) is single loop or dual loop.

Methods And Results: In 12 consecutive patients with counterclockwise (CCW) AFL, entrainment mapping was performed with evaluation of atrial electrograms from the tricuspid annulus (TA) and the posterior right atrial (RA) area. We hypothesized that a dual-loop reentry could be surmised from "paradoxical delayed capture" of the proximal part of the circuit having a longer interval from the stimulus to the captured beat compared with the distal part of the circuit.

Vagal activity modulates spontaneous augmentation of ST elevation in the daily life of patients with Brugada syndrome.

Introduction: In Brugada syndrome, ventricular fibrillation (VF) occurs mainly during sleep, and Brugada ECG signs are intensified by parasympathomimetic drugs; therefore, vagal activity could be a precipitating factor of VF. The aim of the present study was to elucidate the relation between spontaneous augmentation of ST elevation and changes in autonomic nervous activities in the daily life of patients with Brugada syndrome.

Methods And Results: Twenty-three consecutive patients with Brugada syndrome were studied.

Enalapril prevents perpetuation of atrial fibrillation by suppressing atrial fibrosis and over-expression of connexin43 in a canine model of atrial pacing-induced left ventricular dysfunction.

Unlabelled: Effects of enalapril on a canine model of atrial pacing-induced atrial fibrillation (AF) with rapid ventricular responses were determined.

Methods: Four weeks of atrial rapid pacing was performed on twenty-four beagles pretreated with placebo (Group I, n = 14) or enalapril 1 mg/kg (Group II, n = 10). Atrial effective refractory period (ERP), P-wave width, duration of AF, and left ventricular ejection fraction (LVEF) were evaluated every week.

Repolarization abnormality in idiopathic ventricular fibrillation: assessment using 24-hour QT-RR and QaT-RR relationships.

Introduction: We evaluated the characteristics of QT-RR and QaT (apex of T wave)-RR relationships in patients with idiopathic ventricular fibrillation (IVF) compared with control subjects. We hypothesized that IVF patients have unique repolarization dynamics related to a reduced fast Na current and a prominent transient outward current.

Methods And Results: The study group consisted of 9 men (age 47 +/- 10 years) with IVF (6 with Brugada type and 3 with non-Brugada type) who had experienced nocturnal episodes of VF.

Usefulness and safety of bepridil in converting persistent atrial fibrillation to sinus rhythm.

The aim of this study was to investigate the efficacy and safety of bepridil (a multichannel blocker including several potassium channels) for conversion of long-lasting atrial fibrillation (AF). Bepridil restored sinus rhythm alone or in combination with aprindine in 69% of 32 patients with persistent AF lasting > or = 3 months. The time to conversion after starting bepridil was 30 +/- 12 days.

[Brugada syndrome occurring in an identical twin: a case report].

A 51-year-old man was admitted for evaluation of palpitation and syncope. Electrocardiography showed right bundle branch block with ST segment elevation. Intravenous administration of pilsicainide(50 mg) converted the saddle-back type into coved type ST elevation.