Wataru Shimizu

Bio: Wataru Shimizu is an academic researcher from Nippon Medical School. The author has contributed to research in topics: Medicine & Heart failure. The author has an hindex of 76, co-authored 671 publications receiving 23910 citations. Previous affiliations of Wataru Shimizu include Mitsubishi Chemical Corporation & Kumamoto University.

Brugada Syndrome: Report of the Second Consensus Conference Endorsed by the Heart Rhythm Society and the European Heart Rhythm Association

Abstract: Since its introduction as a clinical entity in 1992, the Brugada syndrome has progressed from being a rare disease to one that is second only to automobile accidents as a cause of death among young adults in some countries Electrocardiographically characterized by a distinct ST-segment elevation in the right precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young and otherwise healthy adults, and less frequently in infants and children Patients with a spontaneously appearing Brugada ECG have a high risk for sudden arrhythmic death secondary to ventricular tachycardia/fibrillation The ECG manifestations of Brugada syndrome are often dynamic or concealed and may be unmasked or modulated by sodium channel blockers, a febrile state, vagotonic agents, α-adrenergic agonists, β-adrenergic blockers, tricyclic or tetracyclic antidepressants, a combination of glucose and insulin, hypo- and hyperkalemia, hypercalcemia, and alcohol and cocaine toxicity In recent years, an exponential rise in the number of reported cases and a striking proliferation of articles defining the clinical, genetic, cellular, ionic, and molecular aspects of the disease have occurred The report of the first consensus conference, published in 2002, focused on diagnostic criteria The present report, which emanated from the second consensus conference held in September 2003, elaborates further on the diagnostic criteria and examines risk stratification schemes and device and pharmacological approaches to therapy on the basis of the available clinical and basic science data

The M cell: its contribution to the ECG and to normal and abnormal electrical function of the heart.

Abstract: The discovery and characterization of the M cell, a unique cell type residing in the deep layers of the ventricular myocardium, has opened a new door in our understanding of the electrophysiology and pharmacology of the heart in both health and disease. The hallmark of the M cell is the ability of its action potential to prolong much more than that of other ventricular myocardial cells in response to a slowing of rate and/or in response to agents that act to prolong action potential duration. Our goal in this review is to provide a comprehensive characterization of the M cell, its contribution to transmural heterogeneity, and its role in the normal electrical function of the heart, in the inscription of the ECG (particularly the T wave), and in the development of QT dispersion, T wave alternans, long QT intervals, and cardiac arrhythmias, such as torsades de pointes. Our secondary goal is to address the controversy that has arisen relative to the functional importance of the M cell in the normal heart. The controversy derives largely from the failure of some investigators to demonstrate transmural heterogeneity of repolarization in the dog in vivo under control conditions and after administration of quinidine. The inability to demonstrate transmural heterogeneity under these conditions may be due to the use of bipolar recording techniques that, in our experience, seriously underestimate transmural dispersion of repolarization (TDR). The use of sodium pentobarbital and alpha-chloralose as anesthesia also is problematic, because these agents reduce or eliminate TDR by affecting a variety of ion channel currents. Finally, attempts to amplify transmural dispersion of repolarization with an agent such as quinidine must take into account that relatively high concentrations can result in effects opposite to those desired due to drug inhibition of multiple ion channels. These observations may explain the inability of earlier studies to detect the M cell.

Sodium Channel Block With Mexiletine Is Effective in Reducing Dispersion of Repolarization and Preventing Torsade de Pointes in LQT2 and LQT3 Models of the Long-QT Syndrome

Abstract: Background This study examines the contribution of transmural heterogeneity of transmembrane activity to phenotypic T-wave patterns and the effects of pacing and of sodium channel block under conditions mimicking HERG and SCN5A defects linked to the congenital long-QT syndrome (LQTS). Methods and Results A transmural ECG and transmembrane action potentials from epicardial, M, and endocardial or Purkinje cells were simultaneously recorded in an arterially perfused wedge of canine left ventricle. d-Sotalol was used to mimic LQT2, whereas ATX-II mimicked LQT3. d-Sotalol caused a preferential prolongation of the M cell action potential duration (APD90, 291±14 to 354±35 ms), giving rise to broad and sometimes low-amplitude bifurcated T waves and an increased transmural dispersion of repolarization (TDR, 51±15 to 72±17 ms). QT interval increased from 320±13 to 385±37 ms. ATX-II produced a preferential prolongation of the M cell APD90 (280±25 to 609±49 ms) and caused a marked delay in the onset of the T wave and...

2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure

Abstract: ACC/AHA : American College of Cardiology/American Heart Association ACCF/AHA : American College of Cardiology Foundation/American Heart Association ACE : angiotensin-converting enzyme ACEI : angiotensin-converting enzyme inhibitor ACS : acute coronary syndrome AF : atrial fibrillation

Heart Disease and Stroke Statistics—2017 Update: A Report From the American Heart Association

Abstract: WRITING GROUP MEMBERS Emelia J. Benjamin, MD, SCM, FAHA Michael J. Blaha, MD, MPH Stephanie E. Chiuve, ScD Mary Cushman, MD, MSc, FAHA Sandeep R. Das, MD, MPH, FAHA Rajat Deo, MD, MTR Sarah D. de Ferranti, MD, MPH James Floyd, MD, MS Myriam Fornage, PhD, FAHA Cathleen Gillespie, MS Carmen R. Isasi, MD, PhD, FAHA Monik C. Jiménez, ScD, SM Lori Chaffin Jordan, MD, PhD Suzanne E. Judd, PhD Daniel Lackland, DrPH, FAHA Judith H. Lichtman, PhD, MPH, FAHA Lynda Lisabeth, PhD, MPH, FAHA Simin Liu, MD, ScD, FAHA Chris T. Longenecker, MD Rachel H. Mackey, PhD, MPH, FAHA Kunihiro Matsushita, MD, PhD, FAHA Dariush Mozaffarian, MD, DrPH, FAHA Michael E. Mussolino, PhD, FAHA Khurram Nasir, MD, MPH, FAHA Robert W. Neumar, MD, PhD, FAHA Latha Palaniappan, MD, MS, FAHA Dilip K. Pandey, MBBS, MS, PhD, FAHA Ravi R. Thiagarajan, MD, MPH Mathew J. Reeves, PhD Matthew Ritchey, PT, DPT, OCS, MPH Carlos J. Rodriguez, MD, MPH, FAHA Gregory A. Roth, MD, MPH Wayne D. Rosamond, PhD, FAHA Comilla Sasson, MD, PhD, FAHA Amytis Towfighi, MD Connie W. Tsao, MD, MPH Melanie B. Turner, MPH Salim S. Virani, MD, PhD, FAHA Jenifer H. Voeks, PhD Joshua Z. Willey, MD, MS John T. Wilkins, MD Jason HY. Wu, MSc, PhD, FAHA Heather M. Alger, PhD Sally S. Wong, PhD, RD, CDN, FAHA Paul Muntner, PhD, MHSc On behalf of the American Heart Association Statistics Committee and Stroke Statistics Subcommittee Heart Disease and Stroke Statistics—2017 Update

Harrison's Principles of Internal Medicine

Abstract: The 11th edition of Harrison's Principles of Internal Medicine welcomes Anthony Fauci to its editorial staff, in addition to more than 85 new contributors. While the organization of the book is similar to previous editions, major emphasis has been placed on disorders that affect multiple organ systems. Important advances in genetics, immunology, and oncology are emphasized. Many chapters of the book have been rewritten and describe major advances in internal medicine. Subjects that received only a paragraph or two of attention in previous editions are now covered in entire chapters. Among the chapters that have been extensively revised are the chapters on infections in the compromised host, on skin rashes in infections, on many of the viral infections, including cytomegalovirus and Epstein-Barr virus, on sexually transmitted diseases, on diabetes mellitus, on disorders of bone and mineral metabolism, and on lymphadenopathy and splenomegaly. The major revisions in these chapters and many

2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure

Abstract: ACC/AHA : American College of Cardiology/American Heart Association ACCF/AHA : American College of Cardiology Foundation/American Heart Association ACE : angiotensin-converting enzyme ACEI : angiotensin-converting enzyme inhibitor ACS : acute coronary syndrome AF : atrial fibrillation