BACKGROUND Ambulatory outpatients (n = 150) with a history of paroxysmal supraventricular arrhythmia were studied to establish the characteristics of the first recurrence of symptomatic tachycardia (time to first recurrence, heart rate during tachycardia, and observed rhythm that was regular versus irregular) when no antiarrhythmic drug was being taken. Baseline variables were examined to asses...

BACKGROUND Calcium channel-dependent tissue has been suggested to be involved in the circuit of verapamil-sensitive atrial tachycardia originating from the atrioventricular (AV) node vicinity (V-AT), but little information exists. METHODS AND RESULTS To examine the tachycardia circuit of V-AT, a single extrastimulus was delivered during tachycardia to 10 sites of the intraatrial septum: the e...

A case of macro-reentrant tachycardia associated with a box lesion after thoracoscopis left atrial surgical atrial fibrillation (AF) ablation yet to be described. The goal was to clarify the mechanisms and electrophysiological characteristics of this type of tachycardia. A patient was admitted for an EP study following surgical thoracoscopic AF ablation (box lexion formation by right-sided Cobr...

SUMMARY The purpose of this study was to determine the prevalence of repetitive ventricular responses caused by non-bundle-branch re-entry and bundle-branch re-entry in 47 patients with and in 50 patients without ventricular tachycardia. We also compared the prevalence of repetitive ventricular responses using two types of electrophysiological stimulation: single premature ventri-cular stimulat...

A 29-year-old female patient with Ebstein anomaly was referred to our division for drugresistant symptomatic wide-complex tachycardia. Her preprocedural electrocardiograms showed a sinus rhythm without delta wave and a wide-complex short RP tachycardia with a rate of 150 bpm during palpitation. During conventional electrophysiologic study earliest local activation times during the tachycardia w...

Background—At the mitral annulus–aorta (MA-Ao) junction, the left atrium is continuous through the subaortic curtain with the musculature of the anterior mitral leaflet. Under experimental conditions, this region can generate abnormal electrical activity. In patients with left atrial tachycardia, we investigated whether this region could be the source of this arrhythmia. Methods and Results—In ...

In four patients with WPW syndrome atrial and ventricular premature beats were induced and the changes in form of the ventricular and atrial complexes were studied. Results indicate that, depending upon the timing of the premature atrial beat and the state of refractoriness of the His and Kent bundles, excitation of the ventricles occurs predominantly through the atrioventricular nodal system, ...

This report describes clinical features and tactics of treatment of atrial tachyarrhythmias in infancy. Electrophysiologic study was performed in all 20 infants (2 weeks - 12 months old) in order to determine the mechanism of arrhythmia and to predict the clinical efficacy of management. Reciprocating mechanism was revealed in 12 infants. Atrial flutter was diagnosed for 10 infants among whom o...

INTRODUCTION No prior studies have systematically investigated the diagnostic value of cycle length (CL) variability in differentiating the mechanism of paroxysmal supraventricular tachycardia (PSVT). METHODS AND RESULTS We studied 173 consecutive patients with PSVT; 86 typical atrioventricular nodal reentrant tachycardia (AVNRT), 11 atypical AVNRT, 47 orthodromic reciprocating tachycardia (O...