Heart block
A block in the conduction of the normal electrical impulses in the heart.

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heart block n incoordination of the heartbeat in which the atria and ventricles beat independently due to defective transmission through the bundle of His and which is marked by decreased cardiac output often with cerebral ischemia

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a condition in which conduction of the electrical impulses generated by the natural pacemaker of the heart (the sinoatrial node) is impaired, so that the pumping action of the heart is slowed down. In partial or incomplete heart block conduction between atria and ventricles is delayed (first degree heart block) or not all the impulses are conducted from the atria to the ventricles (second degree heart block). In third degree or complete heart block no impulses are conducted and the ventricles beat at their own slow intrinsic rate (20-40 per minute).
Heart block may be congenital or it may be due to heart disease, including myocardial infarction, myocarditis, cardiomyopathy, and disease of the valves. It is most frequently seen in the elderly as the result of chronic degenerative scarring around the conducting tissue. There may be no symptoms, but when very slow heart and pulse rates occur the patient may develop heart failure or Stokes-Adams syndrome. Symptoms may be abolished by the use of an artificial pacemaker.

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impairment of conduction of an impulse in heart excitation, either permanent or transient and due to anatomical or functional impairment. It is subclassified as first, second, or third degree heart block and is frequently used specifically to denote atrioventricular block.

Medical dictionary. 2011.

Look at other dictionaries:

  • Heart block — Classification and external resources ICD 10 I44 I45 ICD 9 …   Wikipedia

  • heart|block — «HAHRT BLOK», noun, or heart block, an abnormal condition of the heart, caused by a blocking of the nervous tissue that conducts the contracting impulse from the auricle to the ventricle so that they act independently …   Useful english dictionary

  • heart block — heart′ block n. pat a defect in the electrical impulses of the heart resulting in any of various arrhythmias or irregularities in the heartbeat …   From formal English to slang

  • heart block — n. a disorder in which there is defective transmission of impulses regulating the heartbeat, resulting in independent contractions of the atria and ventricles …   English World dictionary

  • heart block — a condition in which conduction of the electrical impulses generated by the natural pacemaker of the heart (the sinoatrial node) is impaired. In partial or incomplete heart block conduction between atria and ventricles is delayed (first degree… …   The new mediacal dictionary

  • heart block — noun recurrent sudden attacks of unconsciousness caused by impaired conduction of the impulse that regulates the heartbeat • Syn: ↑Adams Stokes syndrome, ↑Stokes Adams syndrome, ↑atrioventricular block • Hypernyms: ↑cardiac arrhythmia,… …   Useful english dictionary

  • heart block — Pathol. a defect in the electrical impulses of the heart resulting in any of various arrhythmias or irregularities in the heartbeat. [1900 05] * * * ▪ pathology       lack of synchronization in the contractions of the upper and the lower chambers …   Universalium

  • heart block — noun A disease in the electrical system of the heart, opposed to coronary artery disease, which is disease of the blood vessels of the heart …   Wiktionary

  • heart block — noun Date: 1903 incoordination of the heartbeat in which the atria and ventricles beat independently and which is marked by decreased cardiac output …   New Collegiate Dictionary

  • heart block — /ˈhat blɒk/ (say haht blok) noun a cardiac arrhythmia resulting from a disturbance in the transmission of impulses from the atria to the ventricles …   Australian English dictionary

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