We studied antegrade concealed conduction of atrial extrastimuli (A2) that blocked in the atrioventricular (AV) node in eight subjects, using a third extrastimulus (A3), coupled at decreasing coupling intervals to A2. Three A1-A2 intervals were tested in each subject: late (just shorter than AV nodal effective refractory period), intermediate, and early (just longer than atrial functional refra...

A functional discordance of conductive and refractile properties within atrionodal and AV nodal tissues is thought to be the basis for AV nodal reentrant tachycardia (AVNRT). Contemporary therapy aimed at curing AVNRT without materially damaging normal AV conduction began with surgical AV node modification.' Catheter based techniques with DC shocks and later with radiofrequency energy have been...

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...

In a remarkable series of experiments, the late Gordon Moe and his colleagues1 hypothesized the existence of dual atrioventricular nodal pathways to explain atrioventricular nodal echo complexes elicited in a rabbit model. They postulated existence of an antegrade slow conducting pathway with a shorter refractory period compared with a fast conducting pathway. Thus, premature impulses that bloc...

In a remarkable series of experiments, the late Gordon Moe and his colleagues1 hypothesized the existence of dual atrioventricular nodal pathways to explain atrioventricular nodal echo complexes elicited in a rabbit model. They postulated existence of an antegrade slow conducting pathway with a shorter refractory period compared with a fast conducting pathway. Thus, premature impulses that bloc...

Concealed question noun phrases headed by the definite article have been analysed as contributing the intension of the noun phrase –an individual concept– as semantic argument of the verb. Concealed questions with quantifiers challenge this analysis. Several empirical observations will be presented and an analysis will be sketched that treats this quantification as external to the concealed que...

AIMS Supraventricular tachycardia may trigger atrial fibrillation (AF). The aim of the study was to evaluate the prevalence of supraventricular tachycardia (SVT) inducibility in patients referred for AF ablation and to evaluate the effects of SVT ablation on AF recurrences. METHODS AND RESULTS Two hundred and fifty-seven patients (185 males; mean age: 53.4 ± 14.6 years) referred for AF ablati...