Publications by authors named "Hiroyuki Natsui"
Background: Battery longevity in high-voltage devices (HVDs), specifically implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy-defibrillators (CRT-Ds), is critical for reducing the frequency of generator replacements, minimizing procedural risks, and enhancing patient outcomes. Despite technological advancements, significant variability in battery performance remains among the major manufacturers. This study aimed to evaluate the battery longevity among ICDs and CRT-Ds from the major manufacturers implanted at a single institution and identify the factors influencing battery depletion.
View Article and Find Full Text PDFBackground: Ventricular arrhythmias (VAs) in chronic ischemic heart failure (HF) are associated with high mortality and often refractory to beta-blocker treatment, highlighting the need for alternative therapeutic targets.
Objective: This study investigates the role of neuropeptide Y (NPY), a neurotransmitter released during sympathoexcitation, in the pathogenesis of VAs associated with ischemic chronic HF following myocardial infarction (MI).
Methods: Using a mouse model of ischemic chronic HF after coronary ligation, we employed biochemical, electrophysiological, and calcium ion (Ca) imaging analyses to investigate the proarrhythmic mechanisms of NPY.
Background: Low-voltage areas in the left atrium predict atrial fibrillation recurrence after catheter ablation and are associated with adverse outcomes like death, heart failure, and stroke. Detecting low-voltage areas (LVAs) typically requires invasive procedures, highlighting the need for a simple, minimally invasive marker. Vasoactive intestinal peptide (VIP), a neuropeptide released during parasympathetic stimulation, affects electrophysiological remodeling in atrial fibrillation.
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- Epicardial adipose tissue (EAT) influences atrial fibrillation (AF) but its role in postoperative AF (POAF) is not well understood; this study examines how EAT relates to POAF in cardiovascular surgery patients.
- Out of 53 patients, 34% experienced POAF within a week after surgery, but no major differences in EAT profiles were found between patients with and without POAF.
- Key findings include that higher levels of tumor necrosis factor-alpha (TNF-α) mRNA are linked to increased POAF risk, while larger adipocyte sizes correlate inversely with POAF onset; mitochondrial OXPHOS was unrelated to POAF but associated with secretory activities and adipocyte
Optogenetic termination of atrial tachyarrhythmias by brief pulsed light stimulation.
J Mol Cell Cardiol
May 2023
Article Synopsis
- Scientists are studying a new way to treat a heart problem called atrial fibrillation (AF) using special light instead of painful electric shocks.
- This method uses light to change how cells in the heart behave, which could potentially stop the heart from beating too fast.
- The study found that shining light on the heart cells helped them stay in a normal rhythm, showing that this technique might be a promising and painless treatment for heart issues in the future.
Article Synopsis
- Recent studies indicate that SGLT2 inhibitors like empagliflozin may lower the risk of atrial fibrillation in diabetes patients by reducing oxidative stress linked to mitochondrial-ROS generation.
- In a rat model of type-2 diabetes, treating with empagliflozin improved heart function by reducing atrial tachyarrhythmia, fibrosis, and mitochondrial dysfunction that are exacerbated in diabetes.
- The findings highlight empagliflozin's potential to enhance mitochondrial health and cardiac function, suggesting it could serve as a beneficial treatment for diabetes-related heart issues.
Empagliflozin attenuates arrhythmogenesis in diabetic cardiomyopathy by normalizing intracellular Ca handling in ventricular cardiomyocytes.
Am J Physiol Heart Circ Physiol
March 2023
Article Synopsis
- Diabetic cardiomyopathy increases the risk of fatal ventricular arrhythmias, and the effects of the SGLT2 inhibitor empagliflozin (EMPA) on heart protection have not been extensively studied.
- In experiments using diabetic and control mice, EMPA treatment preserved heart function, reduced premature ventricular complexes during arrhythmia induction, and normalized calcium handling in diabetic cardiomyocytes.
- The improvements seen with EMPA were linked to decreased glucose uptake and reduced autophosphorylation of specific proteins, suggesting that managing glucose levels may help mitigate arrhythmia risks in diabetic heart conditions.
Pharmacological nNOS inhibition modified small-conductance Ca-activated K channel without altering Ca dynamics.
Am J Physiol Heart Circ Physiol
November 2022
Article Synopsis
- Atrial fibrillation (AF) leads to electrical changes in the heart, with the small-conductance Ca-activated K (SK) channel playing a crucial role, though its activation mechanism is still not well understood.
- In a study using rat hearts, researchers inhibited neuronal nitric oxide synthase (nNOS) to explore its effects on atrial tachyarrhythmia (ATA) and used specific blockers to investigate the SK channel's influence on action potential duration (APD) and other parameters.
- The findings revealed that inhibiting nNOS increased ATA inducibility and shortened APD, while the SK channel blocker apamin counteracted these effects without changing calcium transients, suggesting that posttranslational modifications of SK channels may
Background: Electrical storms (ESs) in patients with structural heart disease (SHD) have been reported to be associated with a poor prognosis. However, the detailed cause of death and influence of implantable cardioverter defibrillator (ICD) therapy in ES patients have not been fully investigated. Therefore, we sought to explore the detailed clinical course after an ES and the impact of the ICD therapy in patients with SHDs.
View Article and Find Full Text PDFPurpose: Phrenic nerve injury (PNI) is one of the important complications during cryoballoon (CB) ablation. Recording diaphragmatic compound motor action potentials (CMAPs) during CB ablation can predict PNI. CMAP monitoring may be inaccurate when CMAP amplitudes are low.
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