Robert J. Myerburg

Sudden cardiac death: exploring the limits of our knowledge.

Sudden Cardiac Death. Despite progress in epidemiology, clinical profiling, and interventions, sudden cardiac death remains a major clinical and public health problem. There remain important unresolved issues that are challenges for future progress. Among these are a better understanding of the magnitude of the problem and methods of profiling risk for individuals, the etiology and mechanisms of cardiac arrest in individuals with and without previously identified structural heart disease, clinical strategies for primary and secondary prevention of sudden cardiac death, and further development of community programs for improving cardiac arrest survival in the out‐ofhospital environment. Each of these areas of endeavor and potential progress are reviewed and discussed.

Scientific gaps in the prediction and prevention of sudden cardiac death.

Sudden Cardiac Death. The population impact of sudden death remains an unresolved problem despite growing insights into pathophysiologic mechanisms and therapeutic approaches. To make further progress, basic scientists, clinical investigators, and epidemiologists must merge their efforts to achieve better predictive strategies. Better understanding of basic physiologic mechanisms and integration of multiple points of attack in the cascade of coronary atherosclerosis are required. Identification of genetic markers of risk at all levels of the cascade offer one avenue for improving risk predictions. The epidemiologic strategies must go beyond multivariate analysis to the level complex systems analysis of the multiple components of the cascade. Targets for such approaches are discussed.

Heart Rate Turbulence after Ventricular and Atrial Premature Beats in Subjects without Structural Heart Disease

Introduction: Studies assessing heart rate (HR) behavior after premature beats have focused on HR responses to ventricular premature beats (VBPs), but there is less information of HR behavior after atrial premature beats (APBs).

Regional gradation of L-type calcium currents in the feline heart with a healed myocardial infarct.

ICa in Healed Myocardial Infarction. Introduction: Abnormal action potentials in myocytes adjacent to > 2‐month‐uld feline LV myocardial infarcts (MI) may reflect alterations in Ca2+ currents (ICa).

Impaired negative chronotropic response to adenosine in patients with inappropriate sinus tachycardia

Adenosine and Inappropriate Sinus Tachycardia. Introduction: Adenosine is an endogenous nucleoside that has an important role in the diagnosis and treatment of several cardiac arrhythmias. However, its effects on inappropriate sinus tachycardia (IST) are not well established.

Characteristics of I(K) and its response to quinidine in experimental healed myocardial infarction.

I*, and Quinidine in Healed Infarction. Introduction: Mechanisms and drug treatment of serious ventricular arrhythmias in patients with healed myocardial infarction (HMI) are incompletely understood, in part because the electrophysiology and pharmacology of myocytes from noninfarcted regions of HMI hearts are not well characterized.

Variant ventricular tachycardia

MILIND G. PARIKH, M.D.,* SIDDHARTH A. KAKODKAR, M.D.,† JEFFREY S. NEIGER, M.D.,† ROBERT J. MYERBURG, M.D.,‡ and RICHARD G. TROHMAN, M.D.,† From the *University of Central Florida College of Medicine, Department of Internal Medicine (Cardiovascular), Orlando, Florida; †Department of Internal Medicine, Section of Cardiology, Electrophysiology, Arrhythmia, and Pacemaker Service, Rush University Medical Center, Chicago, Illinois; and ‡Division of Cardiology, University of Miami Miller School of Medicine, Miami, Florida

Nighttime differential autonomic modulation of sinus and idioventricular automaticity and of atrioventricular nodal conduction

Background:Potential differential effects of the autonomous nervous system on sinus node and protected idioventricular automaticity and on atrioventricular nodal conduction have not been assessed in the same patients.