| nuclear pacemaker | A nuclear-powered unit used to generate the electrical current for artificially pacing the heart; replaced by units using long-life nickel-cadmium and other power sources. (05 Mar 2000) |
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| demand pacemaker | A form of artificial pacemaker usually implanted into cardiac tissue because its output of electrical stimuli can be inhibited by endogenous cardiac electrical activity. (05 Mar 2000) |
| diaphragmatic pacemaker | A device that paces the diaphragm, used in patients with chronic ventilatory insufficiency resulting from malfunction of the respiratory control centre on certain types of phrenic nerve malfunction. (05 Mar 2000) |
| ectopic pacemaker | Any pacemaker other than the sinus node. (05 Mar 2000) |
| electric cardiac pacemaker | An electric device that can substitute for the normal cardiac pacemaker, controlling the heart's rhythm by artificial electric discharges. Synonym: electronic pacemaker. (05 Mar 2000) |
| electronic pacemaker | An electric device that can substitute for the normal cardiac pacemaker, controlling the heart's rhythm by artificial electric discharges. Synonym: electronic pacemaker. (05 Mar 2000) |
| electronic pacemaker load | The impedance to the output, the standard load being 500 ohms resistance ± 1%. (05 Mar 2000) |
| transthoracic pacemaker | Artificial pacemaker delivering stimuli through the chest wall usually applied as a temporizing measure in patients with atrioventricular block. (05 Mar 2000) |
| external pacemaker | An artificial cardiac pacemaker whose electrodes for delivering rhythmical electrical stimuli to the heart are placed on the chest wall. (05 Mar 2000) |
| fixed-rate pacemaker | An artificial pacemaker that emits electrical stimuli at a constant frequency. (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) |
| atrioventricular block | <cardiology> A conduction disturbance that results in the inappropriate delay (or complete inability) of a electrical impulse, generated in the atria, to reach the ventricles (via the atrioventricular node). Clinical types are divided into first (nonserious), second and third degree (most serious). Some drugs may precipitate atrioventricular block (for example clonidine, methyldopa, verapamil). A permanent pacemaker may be required for a third degree (complete) heart block. (02 Jan 1998) |
| autonomic nerve block | Interruption of sympathetic pathways, by local injection of an anaesthetic agent, at any of four levels: peripheral nerve block, sympathetic ganglion block, extradural block, and subarachnoid block. (12 Dec 1998) |