For this month’s ECG I am indebted to Esta Felix, 1st year STP trainee at Somerset Foundation Trust and MSc cardiac science student at Newcastle University. The question here is: what is the rhythm?

The patient is a 75-year-old male with a dilated cardiomyopathy who had undergone ablation for atrial fibrillation. He has also been implanted with a CRT pacemaker.  Can you work out the rhythm with confidence from this ECG or is there more than one possibility? If the latter, what are the possibilities, and what additional information might help you to decide which explanation is correct? After there has been some initial discussion, I will post another ECG from the same patient.

Dr Dave Richley

Further Comment Added 21.05.24

Unable to decide with confidence what the rhythm was, I asked if there were any other recordings and luckily Esta managed to supply one. I think this ECG makes everything clear.  Any comments?