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Premature Ventricular Complexes

Epidemiology History Irregularities in pulse and their association with poor outcomes have been recognized for centuries. The Chinese physician Pien Ts’Io, who lived around 6 bce , taught that occasional pulse irregularities did not predict an adverse outcome; however, frequent irregularities (1 in 10 beats) were linked with an ominous prognosis (often resulting in death within a year). Reliable differentiation of PVCs from other arrhythmias became…

Sudden Cardiac Death in Adults

Sudden cardiac death (SCD) is defined as death after a sudden cardiac arrest (SCA) in a patient with either known or previously undetected cardiac abnormalities in whom the mode and time of death are unexpected. Transient endogenous influences on cardiac physiology, such as electrolyte, metabolic, or respiratory disturbances, or exogenous factors, such as drug effects or chest wall trauma (as in commotio cordis ), contribute to…

Typical and Atypical Atrial Flutter: Mapping and Ablation

Atrial flutter (AFL) is one of the most common cardiac arrhythmias in humans, afflicting approximately 0.19 million people in the United States in 2005; its prevalence is expected to increase to 0.44 million by 2050 because of the aging population. AFL often occurs in the context of structural heart disease (e.g., valvular, ischemic heart disease, cardiomyopathy) and may manifest during acute disease process (e.g., sepsis, myocardial…

Left Atrial Appendage Management: Anatomy, Physiology, and Role in Atrial Fibrillation–Related Stroke

Acknowledgment C.R.E. discloses significant research funding (to Vanderbilt University) from Medtronic Inc., Boston Scientific Inc., and Boehringer Ingelheim Inc. He is on the advisory board/consultant for Medtronic Inc., Boston Scientific Inc., AtriCure, Inc., and Abbott Medical Inc. A.N.K. is a speaker for Janssen Pharmaceuticals and Zoll. Left Atrial Appendage Anatomy And Imaging The left atrial appendage (LAA) is formed from the left wall of the primary…

Ablation for Atrial Fibrillation

Background Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with an estimated prevalence of 2% among unselected adults, an increasing prevalence with each decade of life, and a twofold higher risk in men relative to women. , The three most common symptoms directly attributed to AF are impaired exercise tolerance caused by an inappropriate heart rate response during exertion, palpitations caused by an irregular…

Atrial Fibrillation: Mechanisms, Clinical Features, and Management

Atrial fibrillation (AF) is responsible for significant impairment in quality of life and thromboembolism and contributes to substantial morbidity and health care expenditure. AF is the most common arrhythmia in humans. It is heterogeneous in its mechanism, presentation, and clinical course, and therefore patients require individualized treatment. This chapter discusses the epidemiology, nomenclature, current mechanistic insights, and contemporary treatment strategies for the management of AF. Epidemiology…

Preexcitation, Atrioventricular Reentry, Variants

The cardiac electrical impulse normally travels from the atria to the ventricles via the atrioventricular (AV) node, His bundle, bundle branches, and Purkinje fibers. Preexcitation refers to electrical activation of the ventricles via an accessory pathway (AP), occurring earlier than expected via the normal AV conduction system. APs consist of myocardial tissue that bypasses all or part of the normal AV conduction system. These pathways probably…

Junctional Tachycardia

Junctional tachycardia, alternatively known as junctional ectopic tachycardia (JET), originates from the atrioventricular (AV) junction, which encompasses the AV node and His bundle. JET is rarely encountered, especially in the adult population, and its pathogenesis remains incompletely understood. Furthermore, its presentation can be variable, and the diagnosis and therapy can be challenging. This chapter focuses on the tachycardic forms of junctional arrhythmia, although escape rhythms that…

Atrioventricular Nodal Reentrant Tachycardia

Atrioventricular (AV) nodal reentrant tachycardia (AVNRT) was originally proposed to result from reentry confined within the compact AV node. Now, however, AVNRT is thought to involve the AV node, at least two atrionodal connections, and a component of the atrial and/or coronary sinus (CS) myocardium. Much of our current understanding about the components of the reentrant circuits has evolved from the development of ablation procedures in…

Atrial Tachycardia

Introduction Atrial tachycardia (AT) is an important entity in the differential diagnosis of narrow complex tachycardia. It is defined as an arrhythmia that originates in atrial tissue that does not encompass the sinus node. Although nonsustained asymptomatic episodes are frequently seen in routine Holter recordings, the prevalence of this arrhythmia is approximately 5% to 15% in patients referred for routine invasive electrophysiologic evaluation. Definition ATs are…

Supraventricular Tachycardias: Diagnostic Maneuvers in the Electrophysiology Laboratory

Introduction Paroxysmal supraventricular tachycardia (PSVT; Table 70.1 ) refers to a group of heterogenous arrhythmias with different electrophysiologic mechanisms manifesting as a regular narrow complex tachycardia, typically having an abrupt onset and offset. The differential diagnosis for these disorders includes atrioventricular nodal reentrant tachycardia (AVNRT; see Chapter 72 ), atrioventricular reentrant tachycardia (AVRT; see Chapter 74 ), atrial tachycardia (AT; see Chapter 71 ), and junctional…

Genetic Testing

Major advances have been made over the last 3 decades that have defined the genetic basis of many medical diseases. There are now more than 40 different cardiovascular diseases directly caused by variants in genes that encode cardiac proteins. These cardiovascular diseases include inherited cardiomyopathies, inherited arrhythmia syndromes, metabolic disorders, familial aortopathies, and congenital heart diseases. Identification of the genetic causes of cardiovascular disease allows early…

Noninvasive Electrocardiographic Imaging of Arrhythmogenic Substrates and Ventricular Arrhythmias

Acknowledgments This chapter is dedicated to Professor Bruno Taccardi—a scientist, a gentleman, and a dear friend. He will be greatly missed. I am indebted to my outstanding graduate students, research and clinical fellows, and many collaborators who helped make ECGI a reality of great research and clinical promise. Studies presented in this chapter were supported by grants R01-HL33343 and R01-HL49054 from the National Institutes of Health–National…

Autonomic Nervous System Assessment for Syncope and Arrhythmia Risk

Acknowledgment Dr. Benditt is supported in part by a grant provided by the Dr. Earl E. Bakken family in support of heart-brain research. Introduction The autonomic nervous system (ANS) controls multiple critical involuntary “background” functions in virtually all body organs. Some of these activities are controlled by central centers, whereas in other cases (e.g., gastrointestinal motility) there is substantial local autonomy. In any case, if moment-to-moment…

Intracardiac Echocardiography for Electrophysiology

The rapid growth in the complexity of interventional electrophysiology made the inherent limitation of fluoroscopic imaging quite clear. Although three-dimensional (3D) electroanatomic mapping and preprocedural anatomic imaging have been important in augmenting our intraprocedural understanding of cardiac and extracardiac anatomy, these modalities are potentially limited by their artificially static nature and in difficulties with adequate registration. Intracardiac echocardiography (ICE) provides real-time imaging of cardiac and extracardiac…

Magnetic Resonance Imaging for Electrophysiology

Introduction Today’s successful electrophysiologist must not only be a competent proceduralist but also a physician who understands the pathophysiology of arrhythmias, new drug targets and developments, complexities of new technologies, and various treatment options. Additionally, an in-depth understanding of cardiac anatomy, common anatomic variations, typical scar patterns with each pathology, and how anatomic arrhythmia substrates relate to diagnostic and procedural nuances is increasingly important. Advanced imaging…

Computed Tomography for Electrophysiology

This chapter reviews the technical background and current uses of cardiac computed tomography in the diagnosis and management of atrial and ventricular arrhythmias. Imaging plays a fundamental role in the diagnosis and treatment of cardiac arrhythmias. The increased use of imaging has led to an improved ability to understand and successfully treat complex tachycardia circuits. Traditional imaging methods used in the electrophysiology laboratory such as x-ray…

Personal Cardiac Monitoring

Introduction Over the past 30 years, globalization of the Internet and establishment of the smartphone as the dominant computing platform of our time have created enormous cultural shifts. The ability of an individual to instantly access personalized information and services has revolutionized nearly every sector of society including finance, transportation, media, entertainment, travel, and education ( Fig. 63.1 ). U.S. technology companies, now among the leading…

Electrocardiographic Monitoring: Short- and Long-Term Recording

Introduction Ambulatory cardiac monitoring to detect arrhythmias became practical with the development of Holter monitoring and its subsequent derivatives. The clinician is currently armed with an array of tools to provide progressively longer durations of electrocardiogram (ECG) monitoring to obtain a rhythm profile and to establish a symptom rhythm correlation in patients with infrequent symptoms ( Fig. 62.1 ). Clinical trials using traditional skin electrodes, patches,…

Differential Diagnosis of Narrow and Wide Complex Tachycardias

Introduction The differential diagnosis of tachycardias using the electrocardiogram (ECG) remains among the most difficult problems faced by cardiologists in daily practice. Distinguishing supraventricular tachycardias (SVTs) from ventricular tachycardias (VTs) has obvious importance because treatments are very different. This chapter explores the tools available to address the diagnosis; after this has been obtained, further evaluation and treatment strategies generally flow naturally. An important distinguishing feature for…