Toxic T wave

We begin this series with a ECG rhythm strip (Figure 1: R_0001) from a 25 year old man found unconscious on the floor after an overdose with an unknown drug.

Figure_1.

Figure_1.

Describe the ECG changes and the rhythm(s)

The 12 lead ECG of this man is shown in R_0001_ECG (Figure 2).

Figure_2

Figure_2

What is the most likely diagnosis?

What is the immediate management?

Comment on the changes in V1 to V3