| heart conduction system | An impulse-conducting system composed of modified cardiac muscle and having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart. (12 Dec 1998) |
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| saltatory conduction | A method of neuronal transmission in vertebrate nerves, where only specialised nodes of Ranvier participate in excitation. This reduces the capacitance of the neuron, allowing much faster transmission. See: myelin, Schwann cells. (18 Nov 1997) |
| Purkinje conduction | <neurology, physiology> Conduction of the cardiac impulse through the Purkinje system. (05 Mar 2000) |
| H-R conduction time | 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) |
| H-V conduction time | 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) |
| sinoatrial conduction time | <cardiology, physiology> The time required for an impulse to travel from the sinoatrial node to the atrium; estimated indirectly during asystole by halving the average interval from the premature beat to the following normal sinus beat of the atrium. (05 Mar 2000) |
| 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) |
| 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) |