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What is the difference between complete RBBB and incomplete RBBB?

Answered by
Dr. Priyank Mody


Practicing since :2009

Answered : 898 Questions

Posted on Thu, 10 Sep 2015 in Hypertension and Heart Disease

I'm not sure if I have complete RBBB or IRBBB. The computer interpretation says I have IRBBB but mys QRS is above 120. Does all characteristics of RBBB have to be present (besides just QRS above 120) to have a complete block?)

I noticed my S wave in V1 is of greater amplitude than the R waves, but im not sure how important of an indicator that is.

Thank you
Answered by Dr. Priyank Mody 31 minutes later
Brief Answer:
By all means IRbbb or Rbbb, it's physiological and you need not worry :)

Detailed Answer:
Hello, I am Dr. Mody and I would be addressing your concern,
As I start I would like to tell you that in all probability whether it is incomplete or complete rbbb, it is totally a benign diagnosis and will not affect your life in XXXXXXX means.
Now to facts
1) The only difference between incomplete rbbb and complete rbbb is the duration, if between 110 to 120 m sec it's IRBBB and more than 120 it's Rbbb, however at the difference in miniscule in duration it may be missed diagnosed by naked eye. So if the ecg machine is advance it would diagnose it better in this one condition.
Now if IRBBB, it's physiological and mostly due to lead placement, so forget about it.
If complete rbbb, still it's just 120, mostly it's functional and nothing required for the same.
Also it's the S wave to be deeper and more than 40-50 msec in 1 and avl, ( ie bigger than r, wave) and not in v1 as you said. If larger in v1 it is considered normal.
Just upload the ecg and I will help you with the diagnosis.
Lastly if complete rbbb, just get 2 d echo and chest xray done to rule out any congenital heart disease or lung problem, though not urgent.
Hoping I could help,
Regards Dr Priyank Mody, XXXXXXX
Above answer was peer-reviewed by : Dr. Raju A.T
Follow up: Dr. Priyank Mody 8 hours later
This is also a direct link to the ecg that can be viewed in browser:

I also forgot to ask, is there anything that can widen the QRS duration in the ecg besides just RBBB that I can correct to lower it?

Thanks again
Answered by Dr. Priyank Mody 7 hours later
Brief Answer:
Its just 120 m sec

Detailed Answer:
Thanks for the second link as it was far more clear,
Now the Qrs duration is just 120msec.for your understanding one small square is 40 m sec, so it's just 3 small square. However considering your age and if 2 d echocardiography is normal ruling out congenital heart disease, I will not be worried at all

Lastly do not think a lot about it as I said it's a physiological variant I mean like two ppl may not have same height, face and other features similarly two ecg might not be same, that is the reason when as a cardiologist I would report and ecg I would write 'WNL- within normal limits',
So as I said it will not progress if physiological.
Lastly if you smoke or take pot, or do get breathless sometimes, get lung screening along with echo.
Hoping I could, Regards
Above answer was peer-reviewed by : Dr. Vaishalee Punj

The User accepted the expert's answer

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