Biomaterial Database

Effects of upright posture on atrioventricular nodal reentry and dual atrioventricular nodal pathways. 1988

D E Mann, and M J Reiter

Division of Cardiology, University of Colorado Health Sciences Center, Denver 80262.

The electrophysiologic effects of upright posture (45 degrees upright tilt) were studied in 17 patients with dual atrioventricular (AV) nodal pathways, AV nodal reentry or both. Discontinuous AV nodal conduction curves were observed in 16 patients while supine, but in only 11 patients while upright. Fast pathway refractoriness was shortened: the anterograde fast pathway effective refractory period decreased from 360 +/- 22 to 275 +/- 14 ms (mean +/- standard error of the mean), the anterograde fast pathway block cycle length shortened from 448 +/- 28 to 348 +/- 20 ms and the retrograde fast pathway block cycle length shortened from 425 +/- 29 to 338 +/- 24 ms (all p less than 0.01). The anterograde slow pathway block cycle length shortened from 378 +/- 29 to 316 +/- 17 ms (p less than 0.05). AV nodal reentrant tachycardia was induced in 5 patients while supine (2 sustained, 3 nonsustained) and in 6 patients while upright (4 sustained, 2 nonsustained). Tachycardia cycle length shortened during upright posture, from 413 +/- 30 to 345 +/- 22 ms (p less than 0.01), primarily due to shortened anterograde slow pathway conduction time, from 322 +/- 23 to 268 +/- 20 ms (p less than 0.05). Upright posture thus enhances conduction in patients with dual AV nodal pathways, facilitating AV nodal reentry. Electrophysiologic testing in the upright position may yield additional clinical important information in patients with dual AV nodal pathways.

UI	MeSH Term	Description	Entries
D009431	Neural Conduction	The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.	Nerve Conduction,Conduction, Nerve,Conduction, Neural,Conductions, Nerve,Conductions, Neural,Nerve Conductions,Neural Conductions
D011187	Posture	The position or physical attitude of the body.	Postures
D011446	Prospective Studies	Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.	Prospective Study,Studies, Prospective,Study, Prospective
D012032	Refractory Period, Electrophysiological	The period of time following the triggering of an ACTION POTENTIAL when the CELL MEMBRANE has changed to an unexcitable state and is gradually restored to the resting (excitable) state. During the absolute refractory period no other stimulus can trigger a response. This is followed by the relative refractory period during which the cell gradually becomes more excitable and the stronger impulse that is required to illicit a response gradually lessens to that required during the resting state.	Period, Neurologic Refractory,Periods, Neurologic Refractory,Refractory Period, Neurologic,Tetanic Fade,Vvedenskii Inhibition,Wedensky Inhibition,Inhibition, Vvedenskii,Inhibition, Wedensky,Neurologic Refractory Period,Neurologic Refractory Periods,Neuromuscular Fade,Neuromuscular Transmission Fade,Refractory Period, Neurological,Refractory Periods, Neurologic,Electrophysiological Refractory Period,Electrophysiological Refractory Periods,Fade, Neuromuscular,Fade, Neuromuscular Transmission,Fade, Tetanic,Neurological Refractory Period,Neurological Refractory Periods,Refractory Periods, Electrophysiological,Refractory Periods, Neurological,Transmission Fade, Neuromuscular
D002304	Cardiac Pacing, Artificial	Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.	Pacing, Cardiac, Artificial,Artificial Cardiac Pacing,Artificial Cardiac Pacings,Cardiac Pacings, Artificial,Pacing, Artificial Cardiac,Pacings, Artificial Cardiac
D005117	Cardiac Complexes, Premature	A group of cardiac arrhythmias in which the cardiac contractions are not initiated at the SINOATRIAL NODE. They include both atrial and ventricular premature beats, and are also known as extra or ectopic heartbeats. Their frequency is increased in heart diseases.	Ectopic Heartbeats,Extrasystole,Premature Beats,Premature Cardiac Complexes,Cardiac Complex, Premature,Extrasystoles,Premature Cardiac Complex,Beat, Premature,Beats, Premature,Complexes, Premature Cardiac,Ectopic Heartbeat,Heartbeat, Ectopic,Heartbeats, Ectopic,Premature Beat,Premature Cardiac Complices
D006329	Heart Conduction System	An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.	Conduction System, Heart,Conduction Systems, Heart,Heart Conduction Systems,System, Heart Conduction,Systems, Heart Conduction
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001283	Atrioventricular Node	A small nodular mass of specialized muscle fibers located in the interatrial septum near the opening of the coronary sinus. It gives rise to the atrioventricular bundle of the conduction system of the heart.	AV Node,A-V Node,Atrio-Ventricular Node,A V Node,A-V Nodes,AV Nodes,Atrio Ventricular Node,Atrio-Ventricular Nodes,Atrioventricular Nodes,Node, A-V,Node, AV,Node, Atrio-Ventricular,Node, Atrioventricular,Nodes, A-V,Nodes, AV,Nodes, Atrio-Ventricular,Nodes, Atrioventricular
D013611	Tachycardia, Atrioventricular Nodal Reentry	Abnormally rapid heartbeats caused by reentry of atrial impulse into the dual (fast and slow) pathways of ATRIOVENTRICULAR NODE. The common type involves a blocked atrial impulse in the slow pathway which reenters the fast pathway in a retrograde direction and simultaneously conducts to the atria and the ventricles leading to rapid HEART RATE of 150-250 beats per minute.	Atrioventricular Nodal Re-Entrant Tachycardia,Atrioventricular Nodal Reentry Tachycardia,Atrioventricular Reentrant Tachycardia,Tachycardia, AV Nodal Reentrant,AV Nodal Reentrant Tachycardia,Atrioventricular Nodal Reentrant Tachycardia,Atrioventricular Nodal Re Entrant Tachycardia,Atrioventricular Reentrant Tachycardias,Reentrant Tachycardia, Atrioventricular,Tachycardia, Atrioventricular Reentrant