Typical Atrioventricular Bypass Tracts
Abstract Bypass tracts (BTs) are remnants of the atrioventricular (AV) concaused by incomplete embryological development of the AV annuli and failure of the fibrous separation between the atria and ventricles….
Paroxysmal Supraventricular Tachycardias
Abstract A “supraventricular” origin of a tachycardia implies the obligatory involvement of one or more cardiac structures above the bifurcation of the His bundle (HB), including atrial myocardium, atrioventricular node…
Wide Complex Tachycardias
Abstract Wide complex tachycardia (WCT) is a rhythm with a rate of more than 100 beats/min and a QRS duration of more than 120 milliseconds. Several arrhythmias can manifest as…
Atypical Bypass Tracts
Abstract A working definition of an atypical bypass tract (BT) is a conduction pathway that bypasses all or part of the normal conduction system but is not a rapidly conducting…
Typical Atrial Flutter
Abstract The term typical atrial flutter (AFL) is reserved for a macroreentrant circuit with the activation wavefront rotating clockwise or counterclockwise around the tricuspid annulus and using the cavotricuspid isthmus…
Focal Atrial Tachycardia
Abstract Focal atrial tachycardia (AT) is characterized by atrial activation starting at a small area (focus), from which it spreads out centrifugally. “Focal” implies that the site of origin cannot…
Atrioventricular Nodal Reentrant Tachycardia
Abstract Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common form of paroxysmal supraventricular tachycardia. The exact electroanatomic circuit responsible for AVNRT remains elusive. Current evidence suggests that dual atrioventricular…
Macroreentrant Atrial Tachycardia
Abstract Organized atrial tachycardias (ATs) are broadly categorized as either focal (centrifugal activation originating from a discrete site that incorporates automaticity, triggered activity, and microreentrant mechanisms) or macroreentrant (a relatively…
Atrioventricular Conduction Abnormalities
Abstract Atrioventricular (AV) block can be defined as a delay or interruption in the transmission of an impulse from the atria to the ventricles caused by an anatomical or functional…
Inappropriate Sinus Tachycardia
Abstract Sinus tachycardia is a physiological response to sympathetic activation and/or parasympathetic withdrawal. Inappropriate sinus tachycardia (IST) is a nonparoxysmal tachyarrhythmia characterized by a persistent increase in resting sinus rate…
