Heart Block(redirected from First-degree)
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heart block[′härt ‚bläk]
disruption of the conductivity of the nerve impulse along the conductive system of the heart. Types of heart blocks—intra-auricular (sinoauricular) blocks, au-riculoventricular (atrioventricular) blocks, and blocks of the peduncles of the bundle of His and of the terminal branches—are distinguished depending on the site of the disruption. Heart block may be caused by organic diseases of the myocardium (rheumocarditis, coronary cardiosclerosis), more rarely by intoxications, and also by functional disturbances of the nervous system (neuroses). It may be temporary or permanent, complete or partial. Bradycardia (slowing of the pulse to 18–10 beats per minute) is noted in cases of complete heart block; this leads to severe anemia of the brain accompanied by dizziness, loss of consciousness, and sometimes convulsions. Treatment is directed at eliminating the causes of the heart block.
O. F. BORDIUG