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Assoc Prof Harry Mond
February 23, 2026
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I reported this Holter this week.
The report said ventricular tachycardia (red highlight). What do you think?
Most of you will say atrial fibrillation with a rapid ventricular response and intermittent aberrant ventricular conduction and you will be correct.
We covered the topic a couple of weeks ago (Fun with ECGs 16).
There is, however, a major difference from the usual aberration! Can you pick it?
Firstly, let us briefly review aberration again:
A feature of the right bundle branch block are“rabbit’s” ears; rsR’ in V1:
This was coined by the great teacher of ECGs; Henry “Barny” Marriott in St Petersburg, Florida. He is in the top hat with his ever-devoted fellow on the left.
Why then is the aberration in the first illustration different?
Firstly, there is one bundle branch block (yellow highlight):
Then another (red highlight):
Or both together (red and yellow highlight):
Thus there is aberration involving both bundle branches.
Although right bundle branch block is usually associated with aberration, left bundle branch block can also occur, even in the same patient. This was determined in the early days of electrophysiology studies in the US at a time when half of the published manuscripts in all the cardiology journals were ECG/EP related.
The finding of both bundle branch blocks in the same patient is probably rare, but may not be so, if you look for it.
A final point often asked is whether you can tell the bundle branch block site with a Holter monitor. We always say no, but there are clues.
There are two ways of attaching leads for Holter monitoring with both having some advantages:
On the right is the way CardioScan recommends.
The middle lead is V1 and should be negative or at least isoelectric.
Knowing that we can return to our case study and the yellow highlight is a right bundle branch block with rabbit’s ears.
Once again it is all in the timing.
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October 16, 2026
Retrograde conduction is defined as conduction from an ectopic site to the atrium via the AV node or accessory pathway and referred to as VA conduction. II results in a P wave configuration which differs from an anterograde P wave, and in most ECG leads is inverted. The site from where the impulse originates can be the AV node, Bundle of His, distal conducting system or the body of the ventricles including ventricular pacing. On the ECG, the QRS complex usually precedes the inverted retrograde P wave but on occasion may follow it.
October 1, 2026
In 1970, I commenced work as a “novice” cardiologist at The Royal Melbourne Hospital. Training at that time was learning how to recognise the diastolic murmur of mitral stenosis and making sure the ECG and chest x-rays were the correct way up. As this was prior to coronary artery surgery, stenting and echocardiography, the ECG was a highly respected tool for the diagnosis of many conditions. I was fortunate to befriend a number of the gurus of ECG interpretation who taught me to look into the soul of an ECG. Today, even though the ECG is the first investigation performed by a cardiologist, the art of ECG interpretation has been lost because we depend on the new tools for cardiac diagnosis.Â
September 18, 2026
Dr Thura Thant asked for an opinion on this confusing ECG. By using arrows and highlight, the ECG bared its soul and gave me an answer. ‍See if you can work it out? What do you think?
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