Heart Block

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heart block

[′härt ‚bläk]
The cardiac condition resulting from defective transmission of impulses from atrium to ventricle.

Heart Block


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.


References in periodicals archive ?
To study the prognosis of AV conduction blocks versus Intraventricular conduction defects in patients with acute myocardial Infarction.
161 These results together with the findings from the AMAN rabbits experiments (96) suggested that IgM-induced, complement-mediated injury occurs at the nodes of Ranvier in peripheral motor nerves, and generates conduction block and muscle weakness.
Fainting, near fainting or dizzy spells are the usual symptoms of conduction block, and these should never be ignored
Demyelinated fibers are sensitive to small changes in temperature and electrolytes, which can quickly produce conduction block.
2%) showed conduction blocks, including right bundle branch block (RBBB) in three cases, complete atrioventricular block (AVB) in three cases, complete AVB with RBBB in three cases, left anterior fascicular block (LAFB) in one case, RBBB with LAFB in one case, and Mobitz type II 2[sup]nd degree AVB with RBBB in one case.
1%) patients were without RVI), 26 patients developed conduction block (18 patients (18.
Any kind of conduction block (bundle branch blocks, fascicular blocks).
For amplitude change, a decrease over 20% was interpreted in favor of focal conduction block, as recommended by the American Association of Neuromuscular and Electrodiagnostic Medicine (13).
However, the conduction block identified on routine ulnar motor studies was not matching with clinical findings and other electrodiagnostic findings.
The presence of a diminished amplitude at or proximally to the site of lesion, without TD is defined as conduction block (Figures 5 and 6).
7) According to an ad hoc subcommittee of the American Academy of Neurology, 3 of the following 4 criteria for demyelination should be present on nerve conduction studies to make the diagnosis of CIDP: partial motor-nerve conduction block, reduced motor-nerve conduction velocity, prolonged distal motor latencies, and prolonged F-wave latencies.