bundle-branch block

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bun·dle-branch block (BBB),

intraventricular block due to interruption of conduction in one of the two main branches of the atrioventricular bundle and manifested in the electrocardiogram by marked prolongation of the QRS complex; block of each branch has distinctive QRS morphology.

bundle-branch block

A defect in the passage of electrical impulses through either the right or left branches that divide from the bundle of His, which supply the “wiring” for the right and left ventricles, often resulting in delayed conduction though either bundle branch.

Clinical findings
Generally asymptomatic; if symptomatic, fainting, slowed heart rate.

Cardiomyopathy, myocarditis, infarction, post-surgery.

bun·dle-branch block

Intraventricular block due to interruption of conduction in one of the two main branches of the bundle of His and manifested in the electrocardiogram by marked prolongation of the QRS complex. Block to each branch has distinctive QRS morphology.


1. an obstruction or stoppage.
2. regional anesthesia.

Arthur block
see segmental dorsolumbar epidural block.
bundle-branch block
a form of heart block involving obstruction in one of the branches in the bundle of His.
field block
regional anesthesia obtained by blocking conduction in nerves with chemical or physical agents.
block grazing
see rotational grazing.
heart block
impairment of conduction in heart excitation; often applied specifically to atrioventricular heart block. See also heart block.
inverted L-block
linear infiltration cranial and dorsal to the incision site; used for flank laparotomy in cattle and sheep.
block mating
mating of all the females in a group during a brief period, e.g. within the span of three estral cycles; a characteristic of seasonal animal farming.
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.
nerve block
regional anesthesia secured by injection of an anesthetic in close proximity to the appropriate nerve.
paracervical block
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.
presacral block
anesthesia produced by injection of the local anesthetic into the sacral nerves on the anterior aspect of the sacrum.
ring block
regional anesthesia by the injection of local anesthetic in a complete circle around a limb of a horse, or the teat of a cow.
sacral block
anesthesia produced by injection of the local anesthetic into the extradural space of the spinal canal.
saddle block
the production of anesthesia in a region 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.
sinus block
sinus arrest.
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.
References in periodicals archive ?
3-5) However, intermediate pretest probability patients with baseline ECG abnormalities such as electronically paced ventricular rhythm or left bundle-branch block will require myocardial perfusion imaging.
Risk factors are age 75 or older, Killip class II-IV, and ECG findings indicative of an anterior MI and/or left bundle-branch block.
Bundle-branch block and in-hospital mortality in acute myocardial infarction.
Incidence and clinical relevance of the occurrence of bundle-branch block in patients treated with thrombolytic therapy.
Exclusion criteria were pulseless femoral arteries, a life-threatening arrhythmia, unstable blood pressure, a life expectancy of less than 12 months, contraindication to fibrinolysis, left bundle-branch block, need for mechanical ventilation, previous coronary bypass surgery, renal failure, diabetes treated with metformin, and nonischemic heart disease.
Methods: Fifty-six patients with chronic heart failure and left bundle-branch block (LBBB), who had undergone CRT, with mean age 59.
In 1992, Brugada and Brugada described a new syndrome consisted of right bundle-branch block, ST segment elevation in the right precordial electrocardiogram (ECG) leads and an increased risk of sudden cardiac death (1).
Objective: Cardiac resynchronization therapy (CRT) is an adjunct treatment for heart failure (HF) which associates with left bundle-branch block (LBBB) and is refractory to medical therapy.