What does right bundle branch block mean?

Q. Kindly evaluate my daughter's ECG report.

Answered by
Dr. Rishu Sharma
and medically reviewed by iCliniq medical review team.
This is a premium question & answer published on Dec 30, 2019 and last reviewed on: Jun 20, 2023

Hello doctor,

I would like to send you my daughter's ECG for evaluation. This was taken at the ER. I think she had heartburn. We are now concerned about the abnormal report.



Welcome to icliniq.com.

I have seen the ECG of your daughter. (attachment removed to protect patient identity). She has a condition called right bundle branch block. A right bundle branch block (RBBB) is a heart block in the electrical conduction system. Our heart is divided into four chambers, upper two are called atria and the lower two are called ventricle. Every heartbeat starts from the sino-atrial node in the right atria called pacemaker of the heart and is conducted to ventricles through bundle branches arising from bundle of HIS in the ventricle. The right bundle branch supplies the right ventricle while the left bundle branch supplies the left bundle. During a right bundle branch block, the right ventricle is not directly activated by impulses traveling through the right bundle branch. The left ventricle, however, is still normally activated by the left bundle branch. Though in 85% of adult population RBBB is a normal finding, yet as your daughter is in the pediatric age group it can be because of atrial septal defect also. A detailed history is required before concluding if its atrial septal defect or not. You have not mentioned her symptoms, does she had breathlessness, especially while playing? Does she have chest pain? Any history of recurrent chest infections in her childhood? Why was she taken to ER? Does she have gastritis or acid peptic disorder or heartburn previously? Does she ever had heart palpitation? Is she over fatigued as compared to her friend in doing the same amount of work? I need answers to the above questions before giving a further advice.

Probable diagnosis:

The probable diagnosis might be right bundle branch block or atrial septal defect.

Treatment plan:

Follow up with a detailed history.

Thank you doctor,

She is active in volleyball. She does not get out of breath. No chest infections. She has not had palpitations or rhythm issues. She does not get fatigued. She has had some reflux in the past but not treated. We took her to the ER because she had a pressure in her chest that would not go away. She has complained about this in the past maybe three times a year but always for a shorter time like 15 minutes. She now says that the feeling is mostly when she eats drinks or takes deep breaths. How concerning would atrial septal defect be? And also was concerned about the notes on the possible left atrial abnormality. We are worrying to death about this.



Welcome back to icliniq.com.

Even in case, it is an atrial septal defect it can be treated very easily. Death is not even a rarest possibility. In case even if she has a septal defect she would be admitted for a day and will be discharged in two days after inserting patch for the closure of ASD (atrial septal defect). As she has complained of the same problem in the past also, I would suggest you to to go for a test called 2D echo-cardiography. Left atrial abnormality in case if there is any will be seen in 2D echo, ECG is just a preliminary test and sensitivity is very low to rule out conditions like a left atrial abnormality. Do not be worried by comments of the machine. If the 2D echo is normal the problem is because of gastritis, heart burn for which medicines will be prescribed for a few days. Do not worry at all even if its ASD, a patch will be deployed to close the defect and she will be normal in two or three days post-operation. Follow up with reports of 2D echo of your daughter.

Thank you doctor,

How serious are ejection fraction or a left atrial abnormality? Just in case the echo shows this. Do you see a major issue with the wide or notched P waves on her ECG that would indicate this? She has never had negative symptoms while playing volleyball. We have our first appointment in two weeks. Do you think it is fine to let her practice volleyball in the meantime?



Welcome back to icliniq.com.

RBBB is a normal finding in 85% of population as explained earlier. If left ventricle ejection fraction is normal nothing is to be done and the person can live a normal life with RBBB. The presence of broad, notched (bifid) P waves in lead II is a sign of left atrial enlargement, classically due to mitral stenosis. It is called P mitrale. Bifid P waves (P mitrale) in left atria. Diagnostic criteria of left atrial enlargement based on the following ECG findings a notched P wave in lead II, amplitude of the terminal component of the P wave that descends at least 1 mm below the isoelectric line in lead V1, increased duration of the P wave, terminal portion of the P wave must span at least one small box (40 msec). Ecg of your daughter fulfills only the third criteria out of three. Even if all three criterias are fulfilled an echo will be the gold standard test for making a big diagnosis like left atrial enlargement because the commonest cause of left atrial enlargement is mitral stenosis. A patient with mitral stenosis is definitely going to have symptoms like severe breathlessness because for ECG to pick up changes the disease has to be in a severe or moderate form. But she is a volley ball player highly active therefore left atrial enlargement is a rare possibility. Doctor at ER has circled the p wave in lead three, however, while looking for left atrial enlargement we consider lead number 2. Secondly, her P wave ends below isoelectric line but again in lead V1 it is normal. As of now she can play volley ball.

Thank you doctor,

The one they circled, they kept talking about how the Q area swooped up in a radius instead of a negative Q or a 90 degree angle. You can see where they have drawn this out by hand at the top. They said the radius was abnormal. Do you see any evidence of this or evidence of Wolff Parkinson's white syndrome? Or any other syndrome?



Welcome back to icliniq.com.

Wolff-Parkinson-White (WPW) Syndrome is a combination of the presence of a congenital accessory pathway and episodes of tachyarrhythmia. As told by you she never had palpitations or any rhythm problems. The characteristic ECG pattern is PR interval <120ms, Delta wave- slurring slow rise of an initial portion of the QRS, QRS prolongation >110ms, ST segment and T wave discordant changes i.e. in the opposite direction to the major component of the QRS complex. None of the above criteria or symptoms are seen in your daughter. So do not worry.

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