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…
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…
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…
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…
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…
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…
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…
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…
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…
Basic intervals Basic intervals during sinus rhythm represent a quantitative assessment of the electrical activation of the heart. Normal atrial activation begins at the sinus node, spreads to the low…
