Incomplete left bundle branch block
Jump to navigation
Jump to search
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
In incomplete left bundle branch block, the QRS interval is widened, but is insufficiently prolonged to meet the criteria for left bundle branch block.
Diagnosis
Electrocardiogram
- QRS duration between 110 and 119 ms in adults, between 90 and 100 ms in children 8 to 16 years of age, and between 80 and 90 ms in children less than 8 years of age.
- Presence of left ventricular hypertrophy pattern.
- R peak time greater than 60 ms in leads V4, V5, and V6.
- Absence of q wave in leads I, V5, and V6.
Also a narrow initial R wave in V1 has been linked with a reduced response to CRT.