A 63-year-old man attends the emergency department with complaints of ongoing fatigue, constipation, and a persistently low mood over the past month. He also notes drinking excessive amounts of water and waking several times at night to urinate. On examination, he appears mildly dehydrated but is haemodynamically stable. Blood tests show:
- Adjusted calcium: 2.85 mmol/L (reference range: 2.1–2.6 mmol/L)
- Potassium: 4.0 mmol/L (reference range: 3.5–5.0 mmol/L)
An ECG is performed.
Which of the following is the most likely ECG finding?
