complete heart block

block (blok)

1. obstruction.

2. to obstruct.

3. regional anesthesia.

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ankle block  regional anesthesia of the foot by injection of anesthetic around the tibial nerves at the ankle.

atrioventricular block , AV block impairment of conduction of cardiac impulses from the atria to the ventricles, usually due to a block in the atrioventricular junctional tissue, and generally subclassified on the basis of severity as first, second, or third degree.

Bier block  regional anesthesia by intravenous injection; used for surgical procedures on the arm below the elbow or leg below the knee that are done in a bloodless field maintained by a pneumatic tourniquet.

bifascicular block  impairment of conduction in two of the three fascicles of the bundle branches.

bilateral bundle branch block  (BBBB) interruption of cardiac impulses through both bundle branches, clinically indistinguishable from third degree (complete) heart block.

brachial plexus block  regional anesthesia of the shoulder, arm, and hand by injection of anesthetic into the brachial plexus.

bundle branch block  (BBB) interruption of conduction in one of the main bundle branches, so that the impulse first reaches one ventricle, then travels to the other.

caudal block  anesthesia by injection of local anesthetic into the caudal or sacral canal.

cervical plexus block  regional anesthesia of the neck by injection of a local anesthetic into the cervical plexus.

complete heart block  see heart b.

conduction block  a blockage in a nerve that prevents impulses from being conducted across a given segment although the nerve beyond is viable.

elbow block  regional anesthesia of the forearm and hand by injection of local anesthetic around the median, radial, and ulnar nerves at the elbow.

entrance block  in cardiology, a unidirectional impasse to conduction that prevents an impulse from entering a specific region of excitable tissue; part of the mechanism underlying parasystole.

epidural block  regional anesthesia by injection into the epidural space, either between the vertebral spines, in the cervical, thoracic, or lumbar region, or into the sacral hiatus, which is also called caudal block

Production of epidural block by injection through the ligamentum flavum into the epidural space, the needle stopping just short of the dura mater.

exit block  in cardiology, delay or failure of an impulse to be conducted from a specific region to surrounding tissues.

fascicular block  any of a group of disorders of conduction localized within any combination of the three fascicles of the bundle branches or their ramifications.

femoral block  regional anesthesia of the posterior thigh and the leg below the knee by injection of a local anesthetic around the femoral nerve just below the inguinal ligament at the lateral border of the fossa ovalis.

field block  regional anesthesia by encircling the operative field with injections of a local anesthetic.

first degree heart block  see heart b.; see also atrioventricular b.

heart block  impairment of conduction of an impulse in heart excitation; it is subclassified as first degree when conduction time is prolonged, second degree (partial heart b.) when some atrial impulses are not conducted, and third degree (complete heart b.) when no atrial impulses are conducted; the term and its subcategories are often used specifically for atrioventricular block.

high grade atrioventricular block  second or third degree atrioventricular block.

incomplete heart block  first or second degree heart block.

intraspinal block  spinal anesthesia (1).

intravenous block  Bier b.

lumbar plexus block  regional anesthesia of the anterior and medial aspects of the leg by injection of a local anesthetic into the lumbar plexus.

mental block  blocking (2).

metabolic block  the blocking of a biosynthetic pathway due to a genetic enzyme defect or to inhibition of an enzyme by a drug or other substance.

Mobitz type I block  Wenckebach b.

Mobitz type II block  a type of second degree atrioventricular block in which dropped beats occur periodically without previous lengthening of the P–R interval, due to a block within or below the bundle of His.

motor point block  interruption of impulses, by anesthesia or destruction of the nerve, at a motor point in order to relieve spasticity.

nerve block  regional anesthesia by injection of anesthetics close to the appropriate nerve.

paracervical block  regional anesthesia of the inferior hypogastric plexus and ganglia produced by injection of the local anesthetic into the lateral fornices of the vagina.

parasacral block  regional anesthesia produced by injection of a local anesthetic around the sacral nerves as they emerge from the sacral foramina.

paravertebral block  infiltration of anesthetic into an area near the vertebrae.

partial heart block  see heart b.

periinfarction block  disturbance of intraventricular conduction after a myocardial infarction, due to delayed conduction in the infarct region.

presacral block  anesthesia produced by injection of the local anesthetic into the sacral nerves on the anterior aspect of the sacrum.

pudendal block  anesthesia produced by blocking the pudendal nerves, accomplished by injection of the local anesthetic into the tuberosity of the ischium.

retrobulbar block  that performed by injection of a local anesthetic into the retrobulbar space to anesthetize and immobilize the eye.

sacral block  see under anesthesia.

saddle block  regional anesthesia in an area of the buttocks, perineum, and inner aspects of the thighs, by introducing the anesthetic agent low in the dural sac.

second degree heart block  see heart b.; see also atrioventricular b.

sinoatrial block  delay or absence of the atrial beat due to partial or complete interference with the propagation of impulses from the sinoatrial node to the atria.

spinal block  see under anesthesia.

subarachnoid block  spinal anesthesia (1).

third degree heart block  see heart b.; see also atrioventricular b.

trifascicular block  impairment of conduction in all three fascicles of the bundle branches, a form of complete heart block.

unifascicular block  impairment of conduction in only one fascicle of the bundle branches.

vagal block , vagus nerve block blocking of vagal impulses by injection of a solution of local anesthetic into the vagus nerve at its exit from the skull.

Wenckebach block  a type of second degree atrioventricular block in which one or more dropped beats occur periodically after a series of steadily increasing P–R intervals.

wrist block  regional anesthesia of the hand by injection of a local anesthetic around the median, radial, and ulnar nerves of the wrist.

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complete heart block (CHB)

Etymology: L, complere, to fill up; Gk, kardia, heart; OFr, bloc

total failure of impulses to be conducted from the atria to the ventricles. It causes the atria and ventricles to beat independently. It requires the use of a pacemaker to maintain a normal heart rate. Also called third-degree AV heart block.

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heart block

impairment of conduction in heart excitation; often applied specifically to atrioventricular heart block.

When isolated impulses from the atria fail to reach the ventricles, heartbeats are missed and the block is called incomplete. When no impulses reach the ventricles from the atria the heart block is complete, with the result that the atria and the ventricles beat at separate rates. In this case the beats remain regular but the rate of the ventricular beats is greatly slowed down.

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atrioventricular (A-V) heart block

a form in which the blocking is at the atrioventricular junction. It is first degree when A-V conduction time is prolonged; second degree (partial heart block) when some but not all atrial impulses reach the ventricle; third degree (complete heart block) when no atrial impulses at all reach the ventricle, and the atria and ventricles act independently of each other.

bundle-branch heart block

a form in which one ventricle is excited before the other because of absence of conduction in one of the branches of the bundle of His.

complete heart block

see atrioventricular heart block (above).

fascicular heart block

one originating on one of the two divisions of the left bundle branch. See also hemiblock.

interventricular heart block

bundle-branch heart block.

Mobitz heart block b's

variations of second-degree heart blocks. See also wenckebach's phenomenon.

sinoatrial heart block

partial or complete impairment of conduction from the sinoatrial node to the atria, resulting in delay or absence of an atrial beat.