What Is a Left Bundle Branch Block?

Left bundle branch block is referred to as left bundle branch block, which refers to the delay or block of left bundle branch conduction caused by various reasons. Bundle branch block and left anterior branch and left posterior branch double block. Its incidence is related to age, and the incidence increases with age.

Basic Information

nickname

Left bundle branch block

Visiting department

Cardiology

Multiple groups

Patients with organic heart disease

Common causes

Organic heart disease leads to left ventricular hypertrophy and ischemia, left ventricular dilatation and traction cause damage or rupture of the left bundle branch

Common symptoms

Generally without specific symptoms and signs, the symptoms and signs appear mostly due to the primary disease

Causes of left bundle branch block

Left bundle branch block is rarely seen in healthy people, and most suffer from organic heart disease. Left ventricular hypertrophy and ischemia due to organic heart disease, left ventricular dilatation and traction cause damage or rupture of the left bundle branch can lead to complete left bundle branch block. The pathological significance of incomplete left bundle branch block is similar to that of complete left bundle branch block, except that the lesion is lighter and the left bundle branch is less damaged.

Clinical manifestations of left bundle branch block

Left bundle branch block usually does not have obvious hemodynamic abnormalities, so there are generally no specific symptoms and signs, and the symptoms and signs appearing are mostly caused by the primary disease.

Diagnosis of left bundle branch block

1. Diagnosis of complete left bundle branch block

(1) Change of QRS wave pattern: The left lead (leads V5, V6, , aVL) shows a wide, rough, blunt, and notched R wave. There are no q waves except for aVL lead. Lead V1 and V2 of the right chest are rs type (very small r wave followed by a deep and wide S wave). Leads V1 and V2 are QS, and leads V3 are rarely QS. The chest lead is indexed clockwise. QRS waves of leads III, aVF and aVR are mostly QS type.

(2) QRS wave time limit 0.12s (mostly about 0.14s).

(3) V5, V6 lead wall excitability time (R peak time) 0.06s (mostly> 0.08s), V1, V2 lead wall excitement time is normal.

(4) ST-T changes: The ST-T direction is opposite to the QRS main wave direction. The ST segment of lead V1 is slightly elevated and the T wave is upright; the ST segment of V5 and V6 leads is depressed and the T wave is inverted; The ST segment is depressed, and the T wave is inverted. The ST segment of leads III, avF, and avR tends to rise to varying degrees, with the T wave standing upright.

2. QRS time of incomplete left bundle branch block is less than 0.12s, and the rest is the same as complete left bundle branch block.

Left bundle branch block treatment

Mainly for the cause of treatment.

Prognosis of left bundle branch block

The prognosis of left bundle branch block is closely related to basic heart disease. Where there are many complications or complications based on acute myocardial infarction, especially those with "malignant" arrhythmia, the prognosis is poor.

Prevention of left bundle branch block

1. Actively treat the cause, such as treating coronary artery disease, hypertension, pulmonary heart disease, myocarditis, etc., to prevent the occurrence and development of blockade.

2. Work and rest appropriately, have a moderate diet, live on time, and participate in physical exercise appropriately.