Possible association of papillary muscle hypertrophy with the genesis of J-waves.

Background: Although J-waves have been known to be associated with vulnerability to ventricular fibrillation, their electrophysiologic mechanism remains to be elucidated. The papillary muscles (PMs) of the left ventricle (LV) have been recognized as the target site of radiofrequency ablation for ventricular arrhythmias. However, the relationship between PM hypertrophy and J-waves has not been investigated.

False tendons may be associated with the genesis of J-waves: prospective study in young healthy male.

Background: Recent studies showed that J-waves are associated with vulnerability to ventricular fibrillation. Recently we reported the association between false tendons (FTs) and J-waves in a retrospective study.

Methods And Results: We prospectively studied 50 young healthy men (mean age 24.

Effect of ECG filter settings on J-waves.

Background: While J-waves were observed in healthy populations, variations in their reported incidence may be partly explicable by the ECG filter setting.

Methods: We obtained resting 12-lead ECG recordings in 665 consecutive patients and enrolled 112 (56 men, 56 women, mean age 59.3±16.

Comparison of autonomic J-wave modulation in patients with idiopathic ventricular fibrillation and control subjects.

Background: Although J-waves are seen in both patients with idiopathic ventricular fibrillation (IVF) and the general population, their genesis remains unclear. To assess the relationship between J-waves and autonomic tone we investigated the circadian variation of J-waves in individuals with and without IVF.

Methods And Results: In study 1, we obtained resting 12-lead ECG and Holter ECG recordings in 258 individuals undergoing screening for heart disease.

Electrocardiographic characteristics of patients with false tendon: possible association of false tendon with J waves.

Background: The false tendons (FTs) are fibromuscular bands that transverse the left ventricular cavity and often contain conduction tissue, suggesting that FTs may contribute to the occurrence of ventricular arrhythmias. The presence of J waves is associated with vulnerability to ventricular arrhythmias; however, the mechanisms underlying the manifestation of J waves remain to be elucidated.

Objective: To investigate the electrocardiographic characteristics, including the presence of J waves, in patients with FTs.

Cardioprotective effects of pravastatin against lethal ventricular arrhythmias induced by reperfusion in the rat heart.

Background: Statins are reported to reduce mortality in patients with coronary artery disease and that mortality benefit might be related to the drugs' antiarrhythmic properties.

Methods And Results: Male rats were fed with or without pravastatin (0.1 mg·kg⁻¹·day⁻¹) for 7 days, and thereafter subjected to 10 min of ischemia by coronary artery ligation followed by 20 min reperfusion.

Gender differences in the ST segment: effect of androgen-deprivation therapy and possible role of testosterone.

Background: ST-segment elevation in a structurally normal heart is observed in Brugada- and early repolarization syndrome. The incidence of both syndromes is much higher in males than females. Clinical and basic studies suggest that testosterone plays an important role in ventricular repolarization.

High-glucose condition reduces cardioprotective effects of insulin against mechanical stress-induced cell injury.

Aims: Mechanical stress induces cardiomyocyte injury and contributes to the progression of heart failure in patients with hypertension. In this study, we investigated whether insulin exerts cardioprotective effects against mechanical stretching-induced cell injury, and whether the protective effect is influenced by high-glucose condition.

Main Methods: Cultured neonatal rat cardiomyocytes were plated on silicone chambers, and the cells were mechanically stretched by 15% to induce cell injury.

Mitochondrial K(ATP) channels-derived reactive oxygen species activate pro-survival pathway in pravastatin-induced cardioprotection.

Reactive oxygen species (ROS) are important intracellular signaling molecules and are implicated in cardioprotective pathways including ischemic preconditioning. Statins have been shown to have cardioprotective effects against ischemia/reperfusion injury, however, the precise mechanisms remain to be elucidated. We hypothesized that ROS-mediated signaling cascade may be involved in pravastatin-induced cardioprotection.