Assoc Prof Harry Mond
February 23, 2026
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This is an easy ECG and the interpretation is understanding “what’s in a name”. I reported this ECG on a 63-year old female as normal. I was told that I had missed the diagnosis of sinus arrhythmia and could I amend the report? Who is correct?
Sinus arrhythmia is unusual in a 63-year old. Most cases we see are in the young (<30-years) and occasionally in the elderly. Because of my age, I refuse to give elderly, a figure.This is the classical pattern in a 10-year old.
With inspiration, lungs inflate, and the pulmonary venous blood is compressed into the left atrium, more volume and thus the rate slows. With expiration, there is more room in the thoracic cavity and the pulmonary blood pools, the atrium is relatively empty, and the heart rate becomes faster. Hence the rate oscillations with respiration.Here is another example in a 13-year old.
There is always confusion with atrial ectopy.
Look for an abnormal P wave, surrounded by prematurity and a compensatory pause. In this example, there is both sinus arrhythmia and atrial ectopics.So, what is happening in the first case?Is this sinus arrhythmia? Let us look at the rhythm strip again.
There is rate variation; faster at first and then slow and regular.The person recording the tracing told the patient to take a breath out and hold it as the recording was taken. The heart rate becomes faster and then returns to a slow baseline rate.Same respiratory mechanism as sinus arrhythmia, but not in the spirit of the name as there are no oscillations.I did not amend the report!
Harry Mond
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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