This paper reviews the anatomical substrates responsible for the induction and maintenance of supraventricular tachycardia and discusses the ECG findings associated with these tachycardias. The normal anatomy of the supraventricular conducting system, particularly within the atria, is complex with conduction proceeding along preferential pathway, which are in turn determined in part by the anis...

BACKGROUND In patients late after surgical repair of congenital heart disease (CHD), areas with abnormal electrophysiologic properties may serve as slow conducting pathways within a macroreentrant circuit or may be the source of focal atrial tachycardia. OBJECTIVES The purpose of this study was to evaluate the role of abnormal areas during focal atrial tachycardia prior to ablation. METHODS...

A woman presented during two pregnancies (at 25 and 23 weeks’ gestation, respectively) because the fetuses had rapid, irregular tachycardia and hydrops. After maternal drug treatment and achievement of slower fetal heart rates, the hydrops gradually resolved. Both babies were born full term with continuing atrial fibrillation. In the first, an ectopic atrial rhythm was temporarily achieved duri...

It has been reported that ectopic foci from the pulmonary veins can initiate atrial fibrillation (AF) and can also act as drivers for maintaining AF. However, not all patients with atrial arrhythmias initiate AF. A substrate for atrial propensity to AF is required for AF initiation and maintenance. Thus, we reviewed and discussed mainly the electrophysiological properties observed in AF. Abnorm...

The most common sustained cardiac arrhythmias in humans are atrial tachyarrhythmias, mainly atrial fibrillation. Areas of complex fractionated atrial electrograms and high dominant frequency have been proposed as critical regions for maintaining atrial fibrillation; however, there is a paucity of data on the relationship between the characteristics of electrograms and the propagation pattern un...

Atrial tachycardia is an uncommon arrhythmia and may be focal or macroreentrant. This review concentrates on focal atrial tachycardia. Over the last decade there have been a number of advances in delineating the mechanism and anatomic locations of focal atrial tachycardia. The lack of efficacy of antiarrhythmic therapy and the advent of radiofrequency ablation have altered our primary approach ...

BACKGROUND Right ventricular pacing (RVP) during supraventricular tachycardia produces progressive QRS fusion before the QRS morphology becomes stable. This transition zone (TZ) may provide useful information for differentiating orthodromic reciprocating tachycardia (ORT) from atrioventricular nodal reentrant tachycardia and atrial tachycardia independent of entrainment success. METHODS AND R...

The diagnosis of pseudohypoparathyroidism type 1a (PHP1a) is challenging, because both the osteodystrophy, such as brachydactyly and round face, and the symptomatic hypocalcemia usually develop beyond infancy. Although ectopic calcification may be an early sign of PHP1a, there are no systematic reviews regarding the time of its appearance. We here report on two PHP1a patients who presented with...

INTRODUCTION Acutely, when left atrial ablation is performed during atrial fibrillation (AF), the AF may persist and require cardioversion, or it may convert to sinus rhythm or to atrial tachycardia/flutter. The prevalence of these acute outcomes has not been described. METHODS AND RESULTS Left atrial ablation, usually including encirclement of the pulmonary veins, was performed during AF in ...