1. to obstruct.
atrioventricular block 1.
any interruption of the conduction of electrical impulses from the atria to the ventricles; it can occur at the level of the atria, the atrioventricular node, the bundle of His, or the Purkinje system. See heart block
a type of heart block
in which the blocking is at the atrioventricular junction. It is first degree
when atrioventricular conduction time is prolonged; it is called second degree
when some but not all atrial impulses reach the ventricle; and it is called third degree
when no atrial impulses at all reach the ventricle, so that the atria and ventricles act independently of each other.
Bier block regional anesthesia
by intravenous injection, used for surgical procedures on the forearm or the lower leg; performed in a bloodless field maintained by a pneumatic tourniquet that also prevents anesthetic from entering the systemic circulation. Called also intravenous block
and IV block
bundle branch block
(BBB) a form of heart block
involving delay or failure of conduction in one of the branches in the bundle of His, as determined by an electrocardiogram. It may be complete or incomplete, transient, permanent, or intermittent, and is also named according to involvement of the left or the right bundle branch. It is impossible to determine if bundle branch block is complete or not. When associated with acute anterior wall myocardial infarction, bundle branch block identifies a high-risk patient. See accompanying table.
bundle branch block, bilateral heart block
characterized by conduction disturbance in the right and left bundle branches; it may be alternate, intermittent, or permanent. Complete bilateral bundle branch block results in complete (third degree) atrioventricular block.
bundle branch block, complete heart block
characterized by absence of conduction in a bundle branch or conduction delay, causing ventricular activation to occur largely or exclusively through the contralateral bundle.
bundle branch block, incomplete heart block
characterized by delayed conduction within a bundle branch, resulting in a delay in activation of the ipsilateral ventricle.
bundle branch block, right heart block
characterized by a delay or failure of impulse propagation through the right bundle branch
; it may be either complete or incomplete. See accompanying table.
entrance block a zone of depressed conduction surrounding a pacemaker focus, protecting it from discharge by an extraneous impulse but not necessarily from discharges by electrotonic influences.
exit block heart block
characterized by failure of an expected impulse to emerge from its focus of origin and propagate; this usually occurs with a parasystolic focus, but is also seen with sinus, junctional, and ventricular rhythms. In cardiac pacing
it means that the pacemaker stimulus is not of sufficient amplitude to stimulate the heart, such as when there is a very high threshold
fascicular block heart block
characterized by certain abnormal QRS waveforms ascribed to conduction disturbance in the anterior and posterior divisions of the left bundle branch.
fascicular block, left anterior heart block
characterized by delay or interruption of impulse conduction in the anterior superior division of the left bundle branch
, resulting in asynchronous activation of the left ventricle.
fascicular block, left posterior heart block
characterized by delay or interruption of impulse conduction in the posterior inferior division of the left bundle branch
, resulting in asynchronous activation of the left ventricle.
femoral block regional anesthesia
of the posterior thigh and the lower leg 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 blocking conduction in nerves with chemical or physical agents.
intraventricular block impaired conduction within the ventricles due to absence of conduction within the bundle branches, their ramifications, or the ventricles.
intraventricular block, unspecified
any heart block
characterized by an electrocardiographic pattern of intraventricular conduction disturbance and not qualifying as a bundle branch block or a fascicular block.
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.
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
by injection of a local anesthetic around the sacral nerves as they emerge from the sacral foramina.
presacral block regional anesthesia
produced by injection of the local anesthetic into the sacral nerves on the anterior aspect of the sacrum.
pudendal block regional anesthesia
produced by blocking the pudendal nerves, accomplished by injection of the local anesthetic into the tuberosity of the ischium.
The pudendal block. The pudendal nerves can be effectively blocked by a local anesthetic, thereby anesthetizing the perineum. From Nichols and Zwelling, 1997.
that performed by injection of a local anesthetic
into the retrobulbar space to anesthetize and immobilize the eye.
sacral block regional anesthesia
produced by injection of the local anesthetic into the extradural space of the spinal canal.
saddle block regional anesthesia
in an area corresponding roughly with the areas of the buttocks, perineum, and inner aspects of the thighs, by introducing the anesthetic agent low in the dural sac. Called also saddle block anesthesia.
a type of heart block
characterized by partial or complete interference with the propagation of impulses from the sinoatrial node to the atria, resulting in delay or absence of the atrial response.
an imprecise term referring to heart block
characterized by failure of conduction, partial or complete, in all three of the fascicles of the intraventricular conduction system; i.e., there is simultaneous right bundle branch block, left anterior hemiblock, and left posterior hemiblock. In the setting of acute anterior wall myocardial infarction, this is an ominous sign. More precise terms referring to the specifically involved structures are preferred.
(vagus nerve block
) regional anesthesia
produced by blocking of vagal impulses by injection of a solution of local anesthetic into the vagus nerve at its exit from the skull.
wrist block regional anesthesia
of the hand by injection of a local anesthetic around the median, radial, and ulnar nerves at the wrist.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
Patient discussion about block
Q. what does a sun block cream do? and what are a UV rays?
A. It blocks out harmful Ultra violet rays from the skin as the previous entries have related; however it can also block your ability to produce vitamin D. If you live in a northerly area or one that receives limited sunlight, its recommended to get at least 15 minutes of sun a day (this is probably best done with minimal sunblock) and according to personnal sun sensitivity. Another thing to keep in mind is that sunblock works best if applied 20 minutes before sun exposure.
Q. my son is 5 and half yrs old.he is having veezing and 75%block in one nose because of adenod.is is curable he has taken steriods for one and half yrs but with not much relief for veezing. then we switched on to ayur medicines,where he had some pigmentation at some places in his body. so again we are back to allopathy. he has one nasal steriod spray now with few other medicines. in his last test, dr, said he has adenod about 75% blcok in one nose, he has prescribed medicines for one month. he has also said that a small surgery can be done to remove adenod. i would like to know how long this surgry wil take and how much of rest he wil have to take. and if this adenod is removed, wil his other problem like veezing be cured? indira rajesh
A. it's a pretty common surgery from what i remember. most of our family has any kind of nasal problem...sinusitis..adenoids...just name it. the surgery is entering through the mouth (under full sedation) and lasering/curetting - removed. it took about a week to recover , eating soft foods..and it worked!More discussions about block
This content is provided by iMedix and is subject to iMedix Terms. The Questions and Answers are not endorsed or recommended and are made available by patients, not doctors.