Background: Although sex-dependent differences in cardiac repolarization have been known for many years, few attempts have been carried out to define the individual contribution of each electrocardiographic (ECG) repolarization variable to the sex-dependent pattern.
Method And Results: We analyzed several ECG repolarization variables that reflect both the duration and the rate of repolarization in 500 normal healthy subjects between the ages of 20 and 80 years (250 men and 250 women) and distributed into 5 groups according to age. Cardiac repolarization, measured in the precordial lead exhibiting the highest T-wave amplitude, was found to be shorter and faster in normal men compared with normal women (P <.001). The parameters with the highest individual weight in determining these sex differences were the J point and the ST angle, as indicated by nonlinear (logistic) multivariate regression analysis.
Conclusion: We conclude that changes in the duration and rate of early repolarization are determinants for these sex-dependent ECG pattern differences.
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http://dx.doi.org/10.1067/mhj.2000.108510 | DOI Listing |
Clin Pharmacol Drug Dev
January 2025
GSK, Collegeville, PA, USA.
A randomized, partially blinded, placebo-controlled, crossover study in 48 healthy adults assessed the effect of momelotinib on the heart rate-corrected QT interval (QTc) using the Fridericia formula (QTcF). QTc was evaluated for momelotinib 200 mg (therapeutic dose), momelotinib 800 mg (supratherapeutic dose), moxifloxacin 400 mg (positive control), and placebo. Pharmacokinetic profiles of momelotinib and its active metabolite M21 were evaluated.
View Article and Find Full Text PDFComput Methods Programs Biomed
January 2025
Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan. Electronic address:
Background And Objective: It has been believed that polymorphic ventricular tachycardia (VT) such as torsades de pointes (TdP) seen in patients with long QT syndromes is triggered by creating early afterdepolarization (EAD)-mediated triggered activity (TA). Although the mechanisms creating the TA have been studied intensively, characteristics of the arrhythmogenic (torsadogenic) substrates that link EAD developments to TA formation are still not well understood.
Methods: Computer simulations of excitation propagation in a homogenous two-dimensional ventricular tissue with an anisotropic conduction property were performed to characterize torsadogenic substrates that potentially form TA.
Sci Rep
January 2025
International UNESCO Center for Health-Related Basic Sciences and Human Nutrition, Mashhad University of Medical Sciences, Mashhad, Iran.
Premature ventricular contraction (PVC) is characterized by early repolarization of the myocardium originating from Purkinje fibers. PVC may occur in individuals who are otherwise healthy. However, it may be associated with some pathological conditions.
View Article and Find Full Text PDFPhysiol Rep
January 2025
Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Ishikawa, Japan.
While autonomic dysregulation and repolarization abnormalities are observed in subarachnoid hemorrhage (SAH), their relationship remains unclear. We aimed to measure skin sympathetic nerve activity (SKNA), a novel method to estimate stellate ganglion nerve activity, and investigate its association with electrocardiogram (ECG) alterations after SAH. We recorded a total of 179 SKNA data from SAH patients at three distinct phases and compared them with 20 data from controls.
View Article and Find Full Text PDFOpening of the cardiac voltage-gated Na+ channel (Nav1.5) is responsible for robust depolarization of the cardiac action potential, while inactivation, which rapidly follows, allows for repolarization. Regulation of both the voltage- and time-dependent kinetics of Nav1.
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