a 48 yo male with palpitations

A 48 yo male presents to the emergency department with a complaint of a rapid heart rate. He has been known to be in this before and is usually on Sotalol, but has not taken any for two days. He has also been drinking heavily the night before. He states that at 7.15 that morning he felt his heart start to race suddenly. His ECG is shown below. What is your diagnosis?

This ECG shows an atrial tachycardia with atrial rate of 120bpm. The p waves are inverted in III and aVF, which is abnormal. This is a unifocal atrial tachycardia. It can occur in structurally normal and abnormal hearts. it arises from a particular part of the atrium and its location can be diagnosed by the axis of the p waves.
Below is another example:

This is someone at a rate of 120bpm. Notice the inverted p’s in lead III. Again, this is unifocal atrial tachycardia.
Clinical Presentation
The usual presentation is one of palpitations, but may be that of syncope, or cardiac failure if the patient has been in the rhythm long enough.
Workup
An ECG and electrolytes to ensure no abnormalities and a full blood count to exclude anaemia.
Very few other investigations are needed in the emergency department. Perhaps a chest xray if lung pathology is suspected. The patient should have an echocardiogram, to look for structural abnormalities, but this can be as an outpatient.
Management
The unifocal atrial tachycardia can be treated like an SVT.
The general treatment for this condition is:

1. Pharmacological
   1. Beta blockers
   2. Calcium channel blockers
2. Cardioversion

In this case we gave the patient his usual dose of Sotalol and waited, however it was clear that there was not going to be resolution, so we proceeded to cardiovert.