Thoracic Key

Wolff-Parkinson-White Syndrome and Variants Ventricular preexcitation occurs in 0.1 to 3.1 out of 1,000 people, and is defined as activation of the ventricular myocardium by an atrial impulse earlier than…

Atrial Flutter Clinical Characteristics Atrial flutter is a regular, macro reentrant arrhythmia with an atrial rate of 250 to 320 beats per minute (bpm). The pathophysiology of atrial flutter is…

Atrial Fibrillation Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice. It is both a disease of aging with a prevalence reaching 10% in patients older…

Basic Principles in Clinical Electrophysiology What is Normal and What is Not A thorough understanding of normal cardiac electrophysiology is necessary to accurately identify abnormalities. This chapter will define what…

The Basic Electrophysiology Study The basic electrophysiologic (EP) investigation involves the placement of recording catheters in standard locations in the heart. Catheters with multiple (4 to 10) platinum electrodes through…

Mechanism of Tachycardias Most cardiac arrhythmias can be described as abnormalities of impulse formation, impulse conduction, or a combination of both. For example, the ventricular premature complex (VPC) which initiates…

Cellular Electrophysiology The action potential (AP) is the fundamental electrophysiologic event in cardiac cells. The coordinated flux of ions into and out of the cardiac cell forms the basis for…

Anatomy in Clinical Electrophysiology An understanding of cardiac anatomy is essential to the diagnosis and treatment of arrhythmias. This knowledge is required to allow recording of normal and abnormal electrical…