Term
| what are bundle blocks? what happens to the ekg? |
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Definition
• Normally, both LV and RV are depolarized simultaneously and completed in ~0.10 seconds
• In bundle branch blocks, the ventricles are depolarized in series
• First one ventricle then the other
-This results in:
• Altered QRS morphology
• Widening the QRS complex
• Change the ST segment—T wave |
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Term
| normal ventricular depolarization at V1 and V5/6 |
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Definition
V1- away from apex
V5/V6-towards apex |
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Term
| what causes right bundle branch block? what happens to the ekg? |
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Definition
• A block in the RBB will delay right ventricular depolarization
• Septum will depolarize normally - Septal waves are not affected
• Since the LV is electrically predominant in the normal state, a lack of RV depolarization should not affect this phase at this time
• Following completion of the LV depolarization, the RV depolarizes and the electrical current is directed to the right
- Gives a third phase to the complex |
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Term
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Definition
| right bundle branch block |
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Term
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Definition
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Term
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Definition
| right bundle branch block |
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Term
| ekg criteria list for right bundle branch block |
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Definition
• rSR’ in V1 - Occasionally, qR or R
• Wide S in V6
• QRS complex >0.12 seconds
• Secondary T wave changes in right chest leads
Etiology:
• Normal variant
• Right-sided heart disease: chronic pulmonary disease, pulmonary hypertension, PE, pulmonary valve stenosis
• MI, ischemia
• Chronic degeneration of the conduction system
• May occur after CABG |
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Term
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Definition
| right bundle branch block ekg and criteria |
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Term
| what happens in left bundle branch block? findings? |
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Definition
• Septum is normally depolarized by first part of LBB
• A block in the LBB will cause the septum to depolarize from right to left - Results in a loss of the normal septal waves in V1 and V6
• As the depolarization spreads, the voltages in the LV will still be greater than in the RV - Leads to a qS in V1 and an R wave in V6 with a widened duration
• Entire process of ventricular depolarization will be oriented towards the left chest leads |
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Term
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Definition
| left bundle branch block precordial leads |
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Term
| ekg criteria for left bundle branch block |
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Definition
• Sometimes V1 will have a “notched W” appearance and V6 will have a “notched M” appearance - “Bunny ears”
• QRS complex is widened to =/>0.12 sec
• T wave changes in the left precordial leads - Due to abnormal repolarization
• No septal Q waves |
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Term
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Definition
| left bundle branch block ekg findings |
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Term
| etiologies of left bundle branch block |
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Definition
• LBBB is usually a sign of organic heart disease
-Etiology:
• Valvular heart disease - Aortic stenosis, aortic insufficiency
• Hypertensive heart disease
• Coronary artery disease
• Cardiomyopathy
-New LBBB in the presence of an acute MI may lead to complete heart block
-Frequently associated with LVH |
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Term
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Definition
| left bundle branch block ekg and criteria |
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Definition
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