LBBB


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Related to LBBB: Left bundle branch block

LBBB

Left bundle-branch block

bundle branch block

,

BBB

A defect in the electrical conduction system of the heart in which there is failure of conduction down one of the main branches of the bundle of His. On the surface electrocardiogram, the QRS complex is > 0.12 sec. and its shape is altered. Synonym: bundle branch heart block; interventricularheart block

left bundle branch block

Abbreviation: LBBB
A defect in the conduction system of the heart in which electrical conduction down the left bundle branch is delayed. On the 12-lead EKG, it gives the QRS complex a widened QS complex in lead V1 (0.12 sec.).

right bundle branch block

Abbreviation: RBBB
A defect in the conductive system of the heart in which electrical conduction down the right bundle branch is delayed. On the 12-lead EKG, it gives the widened QRS complex an RSR appearance in leads V1 and V2.

left bundle branch block

Abbreviation: LBBB
A defect in the conduction system of the heart in which electrical conduction down the left bundle branch is delayed. On the 12-lead EKG, it gives the QRS complex a widened QS complex in lead V1 (0.12 sec.).
References in periodicals archive ?
Left bundle branch block (LBBB) is an abnormality of cardiac conduction system which causes delayed activation of left ventricle leading to delayed left ventricular contraction compared to the right ventricle.1 LBBB in children is associated with cardiovascular disease or surgery and is not observed in the general population.
Our study showed the incidence of Intraven-tricular dyssynchrony in LBBB was 124(78%).
Similar results were found in another study conducted by Rao HB et al.5, 72% of patients with LBBB demonstrated intraventricular dyssynchrony.
Our case demonstrates that LBBB in the setting of TAVI may be corrected by pacing at the His bundle.
CRT fastened the [Ca.sup.2+] activation throughout the ventricle in the LBBB condition but insignificantly in the RBBB condition due to the CRT pacing site.
Figure 5 shows the 3D ATP consumption rate, tension, and strain transmural distribution in the sinus, LBBB, LBBB + CRT, LBBB + CRT + LVAD, RBBB, RBBB + CRT, and RBBB + CRT + LVAD conditions.
In patients with LBBB, most the myocardial perfusion studies show false positive results which are wrongly interpreted as fixed or reversible perfusion defects in septal or anteroseptal region of left ventricular myocardium9.
In different reported studies many methods were utilized by the researcher for optimization of MPI results in LBBB. Among those reported studies analysis of Gated myocardial perfusion images and polar map presentations of end diastolic and end systolic images could give better clue of anteroseptal myocardial perfusion status15.
LBBB is rare in those <50 years of age and almost never occurs in those <35 years of age, suggesting that it is an acquired disorder.
People who develop LBBB at a younger age (<45 years) and who are free from cardiovascular risk factors do much better than those who develop LBBB during or after their fifth decade and have associated risk factors.
Exercise tests can be misleading in patients with LBBB. ST-segment responses are unreliable when an exercise ECG is done, and false positive results can occur when either exercise or dobutamine treatment is used with a nuclear scan.
Assessment of a patient with LBBB can also be complicated if the block is rate related--if it only manifests when the patient's heart reaches a certain pumping rate.