BACKGROUND Resetting has been used to characterize reentrant circuits causing clinical tachycardias. METHODS AND RESULTS To determine the mechanisms of resetting, sustained ventricular tachycardia was induced in dogs with 4-day-old myocardial infarctions by programmed stimulation. Premature stimulation was accomplished from multiple regions within reentrant circuits; resetting curves were con...

We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch...

Three patients with recurring attacks of supraventricular tachycardia and no electrocardiographic evidence of the Wolff-Parkinson-White syndrome (WPW syndrome) were studied using intracardiae recordings and atrial stimulation. The findings are interpreted as evidence of a concealed WPW syndrome. In all patients there was antegrade block of the anomalous atrioventricular (A-V) pathway while retr...

Abstract Introduction Inaccurate mapping and ablation of left-lateral concealed AP can result in mitral isthmus conduction block, mimicking concentric retrograde activation. AVRT recurrences are frequent because leaves the through intact. Case Report A 50-years-old patient with history previous ablations underwent third redo procedure due to reoccurrence SVT. Quadripolar catheters were placed H...

Dogs 3-7 days following ligation of the anterior descending coronary artery representing a remarkably stable model for re-entrant ventricular arrhythmias (RVA) and allowed detailed electrophysiologic studies of the re-entrant mechanism. In these dogs, we could regularly illustrate the presence of continuous electrical activity originating from the infarction zone (IZ) and bridging the diastolic...

The linking phenomenon is an electrophysiological phenomenon of conduction between 2 different pathways, such as bundle branches, atrioventricular node (AVN) and accessory pathways. The present study used electrophysiological studies to investigate this phenomenon in 14 patients with dual AVN pathways. Decremental ramp pacing at intervals of 10 ms was carried out in high right atrium until the ...

Three patients with recurring attacks of supraventricular tachycardia and no electrocardiographic evidence of the Wolff-Parkinson-White syndrome (WPW syndrome) were studied using intracardiac recordings and atrial stimulation. The findings are interpreted as evidence of a concealed WPW syndrome. In all patients there was antegrade block of the anomalous atrioventricular (A-V) pathway while retr...

BACKGROUND Concealed retrograde activation has been proposed as a mechanism for antegrade conduction block in the bundle branches and atrioventricular accessory pathways. We studied this hypothesis (linking) in 10 patients with the Wolff-Parkinson-White syndrome in whom antegrade preexcitation could be persistently blocked by overdrive atrial pacing. METHODS AND RESULTS An atrial pacing proto...