Automaticity (postpacing impulse recovery time) of the sinus node or subsidiary pacemakers (or both) was determined by intracardiac recordings and atrial overdrive pacing in three patients with disease of the sinus node. Their electrocardiographic manifestations included sinus bradycardia, sinoatrial block, sinus arrest, afrioventricular junctional rhythm, and atrioventricular dissociation. One...

A patient with recurrent bouts of atrial fibrillation and wide-complex regular tachycardia underwent electrophysiologic studies. Premature atrial stimulation or atrial pacing during sinus rhythm resulted in gradual lengthening of the PR and AH intervals, narrowing of the HV interval and progressive preexcitation with a left bundle branch block and left-axis contour. Induction of tachycardia was...

Regular tachycardia with wide QRS complexes may be difficult to classify as supraventricular (SVT) or ventricular (VT) without electrophysiologic studies. We felt that hemodynamic differences between VT and SVT should allow their distinction by echocardiography. In this study, we utilized high speed M-mode echocardiography in the usual projections in eight patients during tachycardia. Two patie...

Cardiac rhythm abnormalities, including ventricular arrhythmia, atrial fibrillation and atrioventricular block, have been observed during the acute stage of dengue haemorrhagic fever. Atrioventricular or complete heart block can be fatal and may require a temporary pacemaker. We report a ten-year-old girl who presented with dengue haemorrhagic fever with sinoatrial block and atrioventricular di...

Platelets bear receptors for vasoactive peptides such as angiotensin II and vasopressin. The presence of binding sites for another vasoactive peptide, atrial natriuretic factor, was therefore investigated in human platelets. 125I-labeled synthetic atrial natriuretic factor bound specifically to human platelets. Steady-state and kinetic experiments demonstrated the existence of one class of high...

BACKGROUND It has been reported that edrophonium can antagonize the negative chronotropic effect of carbachol. This study was undertaken to evaluate in detail the interaction of edrophonium with muscarinic Mz and M3 receptors. METHODS A functional study was conducted to evaluate the effects of edrophonium on the concentration-response curves for the negative chronotropic effect and the bronch...

BACKGROUND The anatomic-electrophysiological correlation of AV nodal reentry is unclear. To localize reentrant circuits during atrial and ventricular echoes and to characterize sites of slow conduction and block, we correlated histology with electrophysiology of the AV node. METHODS AND RESULTS In 10 isolated dog hearts, extracellular electrical activity was recorded in Koch's triangle at 208...

conclusions: catheter ablation of flutter circuit will not prevent later manifestation of af in 16% of the patients undergoing catheter ablation of the typical afl. bmi was the only independent predictor of af following catheter ablation of the typical afl. objectives; to determine long-term incidence and predictors of af after catheter ablation of typical afl. material and methods: between mar...

A case presenting with AV nodal escape rhythms after obvious sinus depression is described. The escape rhythms arise from two dissociated AV nodal pacemakers with differential physiological properties. Variation in the rate of the upper AV nodal pacemaker results in a form of escape-capture bigeminy. Temporary acceleration of the sinus rhythm results in dissociation between sinus and lower AV n...