A new ECG "quizz" is launched most Monday evenings, in term time.
Cases are generally aimed at Primary Care. All scenarios are completely fictitious, but based on commonly occurring presentations in General Practice.
This is an educational site, intended for healthcare professionals and shouldn't be construed as patient advice.
Please use the Hashtag #ECGclass on Twitter, if you want to ask the patient any questions, or request any further investigations. Alternatively, please join in discussion and leave comments below.
Remember there are no right or wrong answers!
ECG interpretation is often open to debate, and will usually evolve and change as new information becomes available. Everyone's opinion is valid, and useful for others, as the evolution process takes place. Together we will try and form an interpretation based on the trace, and information, we have in front of us. Don't worry if you disagree - shout up and share your thoughts - the diagnosis is often arguable on the basis of a 12 lead trace, and may only become more obvious when a longer rhythm strip is available.
#ECGclass case 27
Back to the wonderful world of everyday-GP-land tonight.
A 19 yr old man comes to see you in surgery. He's worried about some short-lived palpitations he had in the early hours of Sunday morning.
He's usually fit and well with no significant family history of IHD, or sudden unexplained death. He is on no medication. On further questioning he admits the palpitations were an isolated episode after a rather 'heavy' night of alcohol, caffeinated energy drinks, smoking. He denies any use of recreational drugs.
After a thorough history and examination, you are completely happy that this was lifestyle induced, and educate him appropriately. You reassure him that no further investigations are necessary, but to call you again if problematic symptoms return.
He appears to remain anxious and unconvinced, and doesn't seem to want to leave.
What now?
Do you:
a) Smile, stand up and open the door for him?
b) Turn back to your computer and sip your coffee, waiting patiently for him to leave?
c) Explore his concerns?
Update 1
OK. You are feeling benevolent, so you opt for c.
He tells you that he is in the process of applying to the RAF as he hopes to be a fighter jet pilot. He's worried that these recent symptoms may mean something more sinister, which may need 'dealing' with before he attends for his interview/medical. He asks if he could have 'a heart trace or something'.
Do you :
a) Agree to his request and book him for an ECG? (It goes against your clinical judgement, but if it will help reassure him - it's going to be normal after all...).
Or,
b) Do you stand your clinical ground and offer more firm reassurance? (if the RAF are interested, surely it's up to them to investigate)
Update 2
You do the ECG, and this is what you get:
Is it normal?
Check:
Rate: Atrial (P-wave rate) and Ventricular (Q-wave rate)?
Pwaves: Present? Regular? Consistent?
PR Interval: consistent?
QRS:normal shape? size? Duration? Consistently preceeded by a P wave?
ST segments - Are they isoelectric?
QT interval - is it normal duration?
Q1. Does this man's ECG fulfil this definition for sinus rhythm?
(Check the definition of sinus rhythm if you are unsure).
Q2. What about the QRS - does it look normal? Is the duration normal?
(see normal interval values if need)
Final Update/Full Discussion.
I would pass this as a 'normal' ECG.
The rate (approx 54bpm) is a bit slow to be defined as sinus rhythm (SR = 60-100bpm) so we would have to call it a sinus bradycardia.
The P waves are regular and consistent, and each P wave is followed by a QRS.
The PR interval is constant and normal (normal PR interval is 3-5 small squares).
The ST segments, and QT interval, are also normal.
What about the QRS?
Unfortunately it may be a bit tricky to see clearly on this digital reproduction, but there is a slight 'blip' in the QRS conduction. This is seen most clearly in the inferior leads, aVL, and perhaps V1. However, despite this, the QRS isn't broad enough to class this a Bundle Branch Block.
Normal conduction through the ventricles is very fast (0.12 secs - under 3 small squares). In order to diagnose a complete Bundle Branch Block, there has to be some delay in conduction through the ventricles. ie. The QRS complex will be widened to > 0.12secs ( 3 or more small squares).
Some may class this as an "incomplete" Bundle Branch Block - but even so, the rest of BBB criteria aren't really met. Nor is the QRS wide enough to qualify as a more non-specific intraventricular conduction delay. (Intraventricular conduction delay is suggested if a widened QRS is seen, but without the morphological features of LBBB or RBBB).
So - Coupled with his presenting symptoms, I would pass this a normal ECG in a healthy adult. I don't think any further investigations are warranted.
But what will the RAF say?
I have no idea.
If their expert occupational physicians feel that this warrants further specialist investigations on occupational grounds, they will arrange the necessary. Thoughts/comments welcome please!
See a great web resource ECGpedia.org Conduction Delays for a simple and clear definitions of Bundle Branch blocks - complete and incomplete - and Intraventricular conduction delays.
Incomplete RBBB
Here's an example of a more obvious "Incomplete RBBB":
Note the morphological features of RBBB (seen RsR in V1), but the QRS complex is not quite wide enough to diagnoses RBBB (is just under 0.12 secs).
If the same man presented with this ECG and the same history - would that have altered your management?
It shouldn't have. This ECG might be seen in normal healthy hearts, and clinically his symptoms sound more suggestive of benign palpitations/tachycardia, secondary to lifestyle triggers.
If the same man presented with this ECG and the same history - would that have altered your management?
It shouldn't have. This ECG might be seen in normal healthy hearts, and clinically his symptoms sound more suggestive of benign palpitations/tachycardia, secondary to lifestyle triggers.
Complete RBBB
Here on the other hand is a full blown RBBB with widened QRS:
In summary
In Right and Left Bundle branch blocks, or any Intraventricular conduction delay, the QRS complex will be widened.
An RsR pattern ('M' shape) is usually seen most prominently in the lead looking directly at that bundle branch:
RBBB = RsR most prominent in V1/V2
LBBB = RsR most prominent in Leads I and V6.
Usually, The R' (2nd R wave) is larger than the R (1st R defection) - giving a very distorted M shape.
An incomplete RBBB may be seen in normal healthy hearts.
Likewise LBBB may be a normal variant in the elderly, but should raise suspicion of other things if seen in a younger person.
Learning Points:
- RBBB can be a finding normal in healthy hearts.
- Go with your clinical judgement
- Have the confidence of your conviction to state the ECG is within acceptable normal limits.
Thank you. :)