The genesis of complex ventricular rhythms during atrial tachyarrhythmias in humans is not fully understood. To clarify the dynamics of atrioventricular (AV) conduction in response to a regular high-rate atrial activation, 29 episodes of spontaneous or pacing-induced atrial flutter (AFL), covering a wide range of atrial rates (cycle lengths from 145 to 270 ms), were analyzed in 10 patients. AV ...

Our understanding of the variants slow pathway (SP) and associated atypical atrioventricular (AV) nodal reentrant tachycardia (NRT) is still growing. We have identified extending outside Koch’s triangle along tricuspid annulus, including superior, superoanterior inferolateral right atrial SP atypical, fast-slow AVNRT. review history each variant, their electrophysiological characteristics relat...

• • Randomized clinical trials have shown that in most patients with atrial fibrillation (AF), rate control is not inferior to rhythm control as a management strategy. However, the mechanisms of ventricular rate (VR) control during AF remain unclear. Commonly accepted mechanisms are that the complex local atrial wavefronts p...

We directly examined the role of the Ca(v)1.3 (alpha(1D)) Ca(2+) channel in the sinoatrial (SA) node by using Ca(v)1.3 Ca(2+) channel-deficient mice. A previous report has shown that the null mutant (Ca(v)1.3(-/-)) mice have sinus bradycardia with a prolonged PR interval. In the present study, we show that spontaneous action potentials recorded from the SA nodes show a significant decrease in t...

After cardiac transplantation, the denervated donor atria and ventricles demonstrate increased sensitivity to infusions of sympathomimetic amines. Recently, supersensitivity of the canine sinus and atrioventricular (AV) nodes to acetylcholine has also been demonstrated after parasympathetic denervation. Acetylcholine and the endogenous nucleoside adenosine exert similar electrophysiological eff...

BACKGROUND The AV node is frequently the site of reentrant rhythms. These rhythms arise from a slow and a fast pathway for which the anatomic and functional substratum remain debated. This study proposes a new explanation for dual-pathway physiology in which the posterior nodal extension (PNE) provides the substratum for the slow pathway. METHODS AND RESULTS The anatomic and functional proper...

Radiofrequency Ablation of AV node with permanent pacemaker has been used to achieve rate control in persistent symptomatic atrial fibrillation. Although RF Ablation is safe, complications may occur in up to 3% of the procedures. A rare complication of 2nd degree skin burn at indifferent electrode site has been described here. This report highlights the rare but possible complication in patient...

BACKGROUND Fetal and neonatal atrioventricular (AV) reentrant tachycardias can be life-threatening but resolve in most cases during the first year of life. The transient presence of accessory AV myocardial connections during annulus fibrosus development may explain this phenomenon. METHODS AND RESULTS A total of 45 human embryonic, fetal, and neonatal sectioned hearts (4 to 36 weeks of develo...

Intracardiac electrophysiologic studies were performed on 28 infants and children, ages 1 month to 18 years, with the Wolff-Parkinson-White syndrome to try to determine 1) the electrophysiologic characteristics of the accessory connection and 2) the mechanisms of associated supraventricular dysrhythmias. Although the antegrade refractory periods of the normal conduction system were shorter than...

We investigated blocking effects of the selective 8 1-adrenoceptor blocker atenolol (0.1 100 ,ug/kg, i.v.), the selective fl2-adrenoceptor blocker ICI 118,551 (1-1000 ,ug/kg, i.v.) and the com bination of the two drugs on positive chronotropic and dromotropic responses to norepinephrine (NE) released by stimulation of the sympathetic nerves in anesthetized, neurally decentralized, open-chest do...