Orthodromic Reciprocating Tachycardia Introduction Orthodromic reciprocating tachycardia (ORT) is the second most common paroxysmal supraventricular tachycardia (SVT) and the prototypical accessory pathway (AP)-mediated tachycardia. The purpose of this chapter is…

Atrio-ventricular Nodal Reentrant Tachycardia Introduction Atrio-ventricular nodal reentrant tachycardia (AVNRT) is the most common paroxysmal supraventricular tachycardia (SVT). The purpose of this chapter is to: Discuss dual atrio-ventricular (AV) node…

Basic Evaluation of Accessory Pathways Introduction The typical accessory pathway (AP) (bundle of Kent) is a muscle fiber bridging the atrio-ventricular (AV) groove and providing electrical continuity between the atrium…

Long RP Tachycardias Introduction Long RP tachycardias are an unusual type of narrow complex tachycardia (NCT) that includes atrial tachycardia (AT) and four atrio-ventricular (AV) node-dependent tachycardias: 1) pure atypical…

Ablation of Atrio-ventricular Nodal Reentrant Tachycardia Introduction Catheter ablation is a highly effective treatment for atrio-ventricular nodal reentrant tachycardia (AVNRT). While ablation of the fast pathway (FP) was initially performed,…

Narrow Complex Tachycardias Introduction The three major causes of a paroxysmal supraventricular tachycardia (SVT) are 1) atrio-ventricular nodal reentrant tachycardia (AVNRT ˜80%), 2) orthodromic reciprocating tachycardia (ORT ˜15%), and 3)…

Intracardiac Echocardiography Introduction Intracardiac echocardiography (ICE) provides an invaluable tool during invasive electrophysiologic procedures by providing an important link between anatomy and electrophysiology, particularly when integrated with an electro-anatomic map….

Transeptal Catheterization Introduction Transeptal catheterization was originally developed to access the left atrium directly for left-sided hemodynamic measurements.1,2,3,4,5 It has become a mainstay technique of electrophysiologist to provide access for…

Bradycardias Introduction The electrophysiologic (EP) study provides a means to assess sino-atrial node (SAN) function and the integrity of the atrio-ventricular node (AVN)-His-Purkinje axis. The purpose of this chapter is…

Mechanisms of Tachycardia Introduction The three mechanisms responsible for tachycardia are 1) reentry, 2) enhanced automaticity, and 3) triggered activity. Electrocardiographic presentations of tachycardia are mechanism specific including its initiation,…