| sinoventricular conduction | <cardiology, physiology> A rare form of conduction of the sinus impulse during paralysis of the atrial muscle by hyperkalaemia. The impulse leaves the sinus node and enters the internodal tracts rapidly achieving the junctional tissues but without inscribing a P wave due to the inactivation of the atrial muscle cells. (05 Mar 2000) |
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| nerve conduction | The transmission of an impulse along a nerve fibre. (05 Mar 2000) |
| nerve conduction velocity | The rate of impulse conduction in a peripheral nerve or its various component fibres, generally expressed in meters per second. (05 Mar 2000) |
| decremental conduction | Impaired conduction in a portion of a fibre because of progressively lessening response of the unexcited portion of the fibre to the action potential coming toward it; it is manifested by decreasing speed of conduction, amplitude of action potential, and extent of spread of the impulse. (05 Mar 2000) |
| supranormal conduction | Transmission of an impulse during the brief period of the cardiac cycle when it would be expected to fail if it occurred outside this time interval. Compare: supranormal excitability. (05 Mar 2000) |
| delayed conduction | First-degree A-V block. See: atrioventricular block, intraventricular block, bundle-branch block. (05 Mar 2000) |
| synaptic conduction | The conduction of a nerve impulse across a synapse. (05 Mar 2000) |
| intra-atrial conduction | Conduction of the cardiac impulse through the atrial myocardium, represented by the P wave in the electrocardiogram. (05 Mar 2000) |
| intra-atrial conduction time | The total duration of electrical activity of the atria in one cardiac cycle. (05 Mar 2000) |
| intraventricular conduction | Conduction of the cardiac impulse through the ventricular myocardium, represented by the QRS complex in the electrocardiogram. H-R conduction time is from the onset of the first high frequency component of the His bundle electrogram to the onset of the QRS complex of the surface electrocardiogram (normally 43 ± 12 msec); H-V conduction time is from the onset of the first high frequency component of the His bundle electrogram to the onset of the ventricular electrogram (normally approximates the H-R interval but may be a little shorter). Synonym: ventricular conduction. (05 Mar 2000) |
| orthograde conduction | Conduction in the expected normal direction between any cardiac structures. Synonym: antegrade conduction, forward conduction, orthograde conduction. (05 Mar 2000) |
| forward conduction | Conduction in the expected normal direction between any cardiac structures. Synonym: antegrade conduction, forward conduction, orthograde conduction. (05 Mar 2000) |
| alveolocapillary block | The presence of material that impairs the diffusion of gases between the air in the alveolar spaces and the blood in alveolar capillaries; block can be caused by oedema, cellular infiltration, fibrosis, or tumour, and results in undersaturation of peripheral arterial blood with oxygen. (05 Mar 2000) |
| anterograde block | Conduction block of an impulse traveling anywhere in its ordinary direction, for example, from the sinoatrial node toward the ventricular myocardium. (05 Mar 2000) |
| arborization block | Intraventricular block supposedly due to widespread blockage in the Purkinje ramifications and manifested in the electrocardiogram by a pattern similar to bundle-branch block but with complexes of low amplitude. (05 Mar 2000) |