Definitions Ventricular tachycardia (VT) is defined as a tachycardia (rate > 100 beats per minute [bpm]) with three or more consecutive beats that originates in the ventricles. , Accelerated idioventricular rhythm denotes a ventricular rhythm less than 100 bpm. Sustained…
Definitions The anatomic basis of atrioventricular reentrant tachycardia (AVRT) is an abnormal connection ( accessory pathway [AP] ) between the atrial and ventricular myocardium. One limb of the reentrant circuit is the atrioventricular (AV) node and the other is the…
Atrioventricular nodal reentrant tachycardia Definition Atrioventricular nodal reentrant tachycardia (AVNRT) denotes reentry in the area of the atrioventricular (AV) node. Several models have been proposed to explain the mechanism of the arrhythmia in the context of the complex anatomy of…
Definitions and classification Atrial fibrillation (AF) is characterized by uncoordinated atrial activation without effective atrial contraction. On the electrocardiogram (ECG), AF is characterized by rapid oscillations or fibrillatory waves that vary in amplitude, shape, and timing; that usually have a…
Atrial premature beats An atrial premature beat (APB) is characterized by a nonsinus P wave that occurs before the next anticipated sinus beat. Several electrocardiographic leads may be needed to distinguish P waves originating in the sinus node versus an…
Wide-QRS tachycardias can be ventricular tachycardia (VT), supraventricular tachycardia (SVT) conducting with bundle branch block (BBB) aberration or through a bystander accessory pathway (AP), or an AP-mediated tachycardia, with reported proportions of 80%, 15%, and 5%, respectively. , The correct…
Narrow-QRS complexes (≤120 ms) are due to activation of the ventricles via the His-Purkinje system, consistent with origin of the arrhythmia above or within the His bundle. However, early activation of the His bundle can also occur in high septal…
Sinus bradycardia Sinus rates less than 60 beats per minute (bpm) are defined as bradycardia in adults. , Lower rates are common in well-trained athletes and occasionally in the young. During sleep the sinus rate may fall to 35 bpm…
Radiofrequency ablation Radiofrequency (RF) ablation induces tissue necrosis by heating the targeted tissue. Most cardiac ablation systems deliver RF energy between a unipolar platinum-iridium electrode at the tip of the ablation catheter and a large dispersive grounding patch on the…
Electroanatomic mapping Theoretical considerations During conventional electrophysiology (EP) procedures, catheters are manually navigated with the use of single or bi-plane fluoroscopy. An inherent limitation of fluoroscopic navigation is that orientation of the catheter relative to the cardiac anatomy can only…