Atrial tachycardias
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 junctional tachycardias
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…
Atrial fibrillation
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…
Differential diagnosis of wide-QRS (>120 ms) tachycardias
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 and magnetic guidance systems
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…
Physics of ablation
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 and atrial and ventricular conduction curves
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…
Investigation of bradycardias
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….
Vascular access and catheter placement
Patient preparation Patients should be studied in the postabsorptive state and after beta blockers or other antiarrhythmic agents have been discontinued for at least 5 days. Amiodarone should be withdrawn…
Cardiac anatomy for the electrophysiologist
Some of the descriptive terms conventionally used for cardiac structures are inaccurate. Conventionally the heart and its associated structures have been described in accordance with their position when the heart…
