THE CONCEPT of concealed conduction was introduced into electrocardiography to explain a lengthening of, or change in, the refractory period of the atrioventricular conduction system caused either by atrial activity that fails to propagate to the ventricles or by ventricular activity that fails to reach the atria. Standard electrocardiograms do not provide a direct demonstration of the partial ...

We examined the effects of stellate ganglia stimulation on the phase-dependent chronotropic and dromotropic responses to brief vagal bursts in open-chest anesthetized dogs. Stellate stimulation affected the phasic vagal effects on heart rate by shortening the latent period, shifting the phase at which maximum decrease in heart rate occurred to earlier phases, and reducing the maximum decrease i...

Background and objectives: The ideal drug for treatment of a wide range of supraventricular arrhythmia hasn't yet been developed. Previous studies have shown antihypertensive and negative inotropic effects of the Urtica dioica L. (nettle). Therefore, the aim of present study is to determine the rate dependent inhibitory effects of ethanol extract of nettle roo...

Three patients with accessory nodoventricular pathways and re-entry tachycardia are reported. In all three patients the accessory nodoventricular pathway formed the anterograde limb of the re-entry circuit while the His-Purkinje-atrioventricular node axis formed the retrograde limb of the tachycardia in two of the patients and a concealed accessory pathway formed the retrograde limb in the rema...

A novel type of cardiac myosin heavy chain, immunologically related to the myosin isoforms expressed during skeletal muscle development, has recently been described in sinoatrial and atrioventricular nodal fibers of the adult bovine heart (Gorza et al, J Cell Biol 1986; 102:1758-1766). The tissue-specific expression of this myosin type has been utilized in the present study to investigate the d...