Assoc Prof Harry Mond
February 23, 2026
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ECG report stated: “Atrial and ventricular bigeminy”.
What do you think?
On superficial inspection, there is sequential atrial bigeminy (red highlight) and broad QRS ectopic bigeminy (yellow highlight).
Are the wide QRS complexes ventricular? Maybe not!
The ectopic coupling intervals are not constant, but gradually shorten (red arrows).
The wide QRS ectopics have a very short coupling interval and are conducted to the ventricle in the refractory period resulting in progressive left bundle branch block aberration.Before total AV block occurs, the coupling interval once again lengthens and the next ectopic conducts normally.
Therefore, all the ectopics are atrial.
Normally “unifocal” atrial bigeminy will have fixed coupling intervals. Why then do the atrial ectopic coupling intervals, progressively shorten?
Indeed, is this atrial ectopy?
Let us review the cycling period of the ectopics.
The cycling period of the“ectopics” or inter-ectopic intervals are fixed (blue arrows) and in the presence of varying coupling intervals, consider atrial parasystole.
Atrial parasystole:
Remember the hallmarks of atrial parasystole:
In contrast atrial bigeminy:
We have previously discussed ventricular parasystole. With both, the diagnosis is always difficult, controversial and this even applies to cases in the literature.
To be absolutely sure, we need long strips.
Finally, our ECG original report said: “Atrial and ventricular bigeminy”.
Can they occur sequentially?
Sequential atrial bigeminy (red highlight) and ventricular bigeminy (yellow highlight).
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.
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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