Atrial tachycardia or atrial flutter

Educational post

Please have a look at the ECG shown below.

Is this atrial tachycardia or atrial flutter?

ECG definition of atrial flutter is atrial rate more than 240 bpm and no isoelectric line between p waves.
Atrial tachycardia will have rate between 120 to 240 bpm with clear isoelectric line between p waves.

However, these two ECG criteria are not specific for any of them.
Atrial tachycardia with higher heart rate is possible and atrial flutter with lower heart rate is possible.
Atrial flutter may have an isoelectric line between p waves because of atriotomy scars causing conduction block.

More important is to identify mechanism of atrial tachycardia during electrophysiological study.
Electrophysiological study gives us a better idea regarding mechanism of atrial tachycardia.

Atrial tachycardia can be focal or macroreentrant. Focal can be because of automaticity, triggered activity or microreentrant cause.

Coming to this case, Here, atrial rate is around 250 / min and there is isoelectric line between two p waves. So, this falls under grey area as per the ECG definition. I would call it atrial tachycardia with slightly higher atrial rate. Some people may call it atypical atrial flutter. Here, terminology doesn’t make a difference on management. However, it is important to recognise that this is not typical atrial flutter.