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