Management of Cardiac Transplant Patients in the Emergency Department Case 2

A 45-year-old man presents to the ED. He had a heart transplant 7 years previously and has been generally well since. For the last 3 days he has been feeling sweaty and breathless. His presentation was prompted by an episode of collapse on his way to bed and falling down the stairs. Fortunately he did not appear to have sustained any significant injury.

This is his ECG. Click on the image to enlarge.

What is the key abnormal finding on the ECG?

What is the most likely diagnosis?

What further investigation would be appropriate to confirm the presence of a significant arrhythmia?

He remains in the observation unit of the ED awaiting a cardiology bed. During the night, he spikes a fever of 38.5°C.

Which one of our options is the most likely diagnosis now?