Publications by authors named "Win-K Shen"

Background: Recognition of the causes of early mortality after ventricular tachycardia (VT) ablation in patients with reduced left ventricular ejection fraction (LVEF) is an essential step toward improving postprocedural outcomes.

Objectives: This study sought to determine the causes of early mortality (≤30 days) after VT ablation in patients with reduced LVEF and to understand further the circumstances surrounding death after the procedure.

Methods: We performed a retrospective analysis of all patients undergoing VT ablation in patients with reduced LVEF from January 1, 2013, to November 10, 2021, at the Mayo Clinic (Rochester, Phoenix, and Jacksonville).

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Aging is associated with increased prevalence of life-threatening ventricular arrhythmias, but mechanisms underlying higher susceptibility to arrhythmogenesis and means to prevent such arrhythmias under stress are not fully defined. We aimed to define differences in aging-associated susceptibility to ventricular fibrillation (VF) induction between young and aged hearts. VF induction was attempted in isolated perfused hearts of young (6-month) and aged (24-month-old) male Fischer-344 rats by rapid pacing before and following isoproterenol (1 μM) or global ischemia and reperfusion (I/R) injury with or without pretreatment with low-dose tetrodotoxin, a late sodium current blocker.

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Sudden cardiac arrest (SCA) is the most common cause of death in the world. This manuscript highlights the various challenges in prevention and early management of SCA and also discusses the current state of SCA awareness. The manuscript also outlines the various national and international initiatives in improving SCA awareness and their impact on improving outcomes in SCA.

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Article Synopsis
  • The study investigates the clinical significance of isolated left bundle branch block (LBBB) without structural heart disease, aiming to understand its potential risks for mortality and cardiomyopathy.* -
  • A retrospective review of 2,522 patients with complete LBBB showed a one-year mortality rate of 7.8% and a 10-year rate of 22%, with low incidences of cardiomyopathy (3.2% at one year and 9.1% at ten years).* -
  • Findings suggest that isolated LBBB does not significantly impact long-term mortality or increase cardiomyopathy risk in patients without structural heart disease or coronary artery disease.*
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The present study investigated the impact of 12 weeks of pulsed electromagnetic field (PEMF) therapy on peripheral vascular function, blood pressure (BP), and nitric oxide in hypertensive individuals. Thirty hypertensive individuals (SBP > 130 mm Hg and/or MAP > 100 mm Hg) were assigned to either PEMF group (n = 15) or control group (n = 15). During pre-assessment, participants underwent measures of flow-mediated dilation (FMD), BP, and blood draw for nitric oxide (NO).

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Traditional transvenous cardiac pacemakers have pitfalls due to lead- and device pocket-related complications. Leadless pacemakers were developed and introduced into clinical practice to overcome the shortcomings of traditional transvenous pacemakers. In this review, we provide a description of leadless pacemaker devices, and summarize existing data on device performance.

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The incidence and prevalence of most cardiovascular disorders increase with age, and cardiovascular disease (CVD) is the leading cause of death and major disability in adults aged 75 and older. Despite the effect of CVD on quality of life, morbidity, and mortality in older adults, individuals aged 75 and older have been markedly underrepresented in most major cardiovascular trials, and virtually all trials have excluded older adults with complex comorbidities, significant physical or cognitive disabilities, frailty, or residence in nursing homes and assisted living facilities. As a result, current guidelines are unable to provide evidence-based recommendations for diagnosis and treatment of older adults typical of those encountered in routine clinical practice.

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The incidence and prevalence of most cardiovascular disorders increase with age, and cardiovascular disease is the leading cause of death and major disability in adults ≥75 years of age; however, despite the large impact of cardiovascular disease on quality of life, morbidity, and mortality in older adults, patients aged ≥75 years have been markedly underrepresented in most major cardiovascular trials, and virtually all trials have excluded older patients with complex comorbidities, significant physical or cognitive disabilities, frailty, or residence in a nursing home or assisted living facility. As a result, current guidelines are unable to provide evidence-based recommendations for diagnosis and treatment of older patients typical of those encountered in routine clinical practice. The objectives of this scientific statement are to summarize current guideline recommendations as they apply to older adults, identify critical gaps in knowledge that preclude informed evidence-based decision making, and recommend future research to close existing knowledge gaps.

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The incidence and prevalence of most cardiovascular disorders increase with age, and cardiovascular disease is the leading cause of death and major disability in adults ≥75 years of age; however, despite the large impact of cardiovascular disease on quality of life, morbidity, and mortality in older adults, patients aged ≥75 years have been markedly underrepresented in most major cardiovascular trials, and virtually all trials have excluded older patients with complex comorbidities, significant physical or cognitive disabilities, frailty, or residence in a nursing home or assisted living facility. As a result, current guidelines are unable to provide evidence-based recommendations for diagnosis and treatment of older patients typical of those encountered in routine clinical practice. The objectives of this scientific statement are to summarize current guideline recommendations as they apply to older adults, identify critical gaps in knowledge that preclude informed evidence-based decision making, and recommend future research to close existing knowledge gaps.

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Background: Cardiac resynchronization therapy (CRT) is an accepted intervention for chronic heart failure (HF), although approximately 30% of patients are non-responders. The purpose of this study was to determine whether exercise respiratory gas exchange obtained before CRT implantation predicts early response to CRT.

Methods: Before CRT implantation, patients were assigned to either a mild-moderate group (Mod G, n = 33, age 67 ± 10 years) or a moderate-severe group (Sev G, n = 31, age 67 ± 10 years), based on abnormalities in exercise gas exchange.

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Article Synopsis
  • - The study aimed to determine how changes in pulmonary capillary blood volume, lung volume, and interstitial fluid affect lung impedance during different positions and exercise in heart failure patients.
  • - Measurements were taken from 12 heart failure patients at rest and during exercise, revealing that lung impedance increased with lung volume and varied when patients changed positions.
  • - Results showed that while lung impedance is influenced by volume and position changes, it does not significantly change with small, acute variations in lung fluid during exercise.
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Atrial fibrillation is the most common arrhythmia affecting patients today. Disease prevalence is increasing at an alarming rate worldwide, and is associated with often catastrophic and costly consequences, including heart failure, syncope, dementia, and stroke. Therapies including anticoagulants, anti-arrhythmic medications, devices, and non-pharmacologic procedures in the last 30 years have improved patients' functionality with the disease.

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Hiatal hernia (HH) causes protrusion of the stomach into the chest cavity, directly impinging on the left atrium and possibly increasing predisposition to atrial arrhythmogenesis. However, such association has not been fully explored. The objective was to determine if an association between HH and atrial fibrillation (AF) exists and whether there are age- and sex-related differences.

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Background: Recent studies have shown that magnetic resonance imaging (MRI) of patients with pacemakers can be safely performed under careful monitoring, but they excluded patients with recently implanted devices. Patients with recent implants may be at a greater risk for complications during MRI imaging due to lack of lead and wound maturity.

Methods: We implemented a clinical protocol for MRI imaging of patients with implanted cardiac devices, and prospectively collected data.

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Objectives: This study sought to identify the risk of sudden cardiac death (SCD) associated with obstructive sleep apnea (OSA).

Background: Risk stratification for SCD, a major cause of mortality, is difficult. OSA is linked to cardiovascular disease and arrhythmias and has been shown to increase the risk of nocturnal SCD.

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Syncope, a clinical syndrome, has many potential causes. The prognosis of a patient experiencing syncope varies from benign outcome to increased risk of mortality or sudden death, determined by the etiology of syncope and the presence of underlying disease. Because a definitive diagnosis often cannot be established immediately, hospital admission is frequently recommended as the "default" approach to ensure patient's safety and an expedited evaluation.

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Premature ventricular complexes (PVCs) are a common occurrence in clinical practice. The clinical presentation may range from asymptomatic to left ventricular (LV) dysfunction with congestive heart failure. The decision to suppress PVCs is largely based on the presence of symptoms, interference with other therapy (e.

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Introduction: The Medtronic Sprint Fidelis implantable cardioverter defibrillator (ICD) lead was "recalled" in October 2007 after 268,000 implants worldwide due to increased failure risk. Manufacturer suggested monitoring has not been shown effective at preventing adverse events. Only limited data exist regarding clinical predictors of Fidelis lead fracture.

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Standardized guidelines for polysomnography (PSG) have not specified methods for acquiring or interpreting electrocardiographic (ECG) data. The practice of single lead ECG monitoring during PSG may allow identification of simple measures of cardiac rhythm but reduces the ability to detect myocardial ischemia and to define cardiac intervals. Although simple measures of cardiac rhythm such as heart rate and cardiac pauses are inherently reliable, there is limited data regarding outcome measures relative to sleep related heart rates and cardiac events during sleep.

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Aims: To determine the impact of surgical myectomy on ventricular arrhythmias in obstructive hypertrophic cardiomyopathy (HCM). Left ventricular outflow tract obstruction (LVOTO) correlates with adverse outcomes, including sudden cardiac death (SCD) in patients with HCM. Surgical myectomy is the primary treatment strategy for relief of symptoms owing to LVOTO and has been hypothesized to decrease the potential for ventricular tachyarrhythmias.

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Deficient bioenergetic signaling contributes to myocardial dysfunction and electrical instability in both atrial and ventricular cardiac chambers. Yet, approaches capable to prevent metabolic distress are only partially established. Here, in a canine model of tachycardia-induced congestive heart failure, we compared atrial and ventricular bioenergetics and tested the efficacy of metabolic rescue with the vasopeptidase inhibitor omapatrilat.

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Background: Inappropriate sinus tachycardia (IAST) and postural orthostatic tachycardia syndrome (POTS) are syndrome complexes with some distinctive features, overlapping clinical manifestations, and potential common mechanisms. Pathogenesis of these overlapping syndromes is poorly understood. Diagnostic and therapeutic approaches have not been standardized.

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