ECG Level 3 Tutorial: Bundle Branch Blocks
Tutorial: Bundle Branch Blocks
Understand why a right bundle branch block and left bundle branch block pattern are created. Learn also the diagnostic criteria.
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Tutorial: Bundle Branch Blocks Incomplete blocks
Lessons
42
Times Practiced
1284
Cases Completed
1h 24m
Total Time spent
1m 24s
Average Time
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1 Anatomy Anatomy
2 General Concepts General Concepts
3 LBBB LBBB
4 RBBB RBBB
Current lesson 5 Incomplete blocks Incomplete blocks
6 Intraventricular Delay Intraventricular Delay
7 Advanced details Advanced details
Incomplete blocks
Incomplete bundle branch blocks essentially share the same diagnostic criteria as complete bundle branch blocks with one difference: the QRS duration is shorter with incomplete blocks.

Remember that the QRS duration for complete blocks is > 120 ms (3 little squares). The QRS duration diagnostic criteria for incomplete bundle branch blocks is 100 - 120 ms. (which is 2.5 - 3 little squares).

Different textbooks might reference different QRS durations.

Here is an example of incomplete LBBB:

With close-ups of V1 and V6:
        


Here is an example of incomplete RBBB:


With close-up looks at V1 and V6: