A 44-year-old man is brought to the emergency department following a collapse and suspected deliberate self-poisoning.
Describe and interpret his initial 12-lead electrocardiogram:
- Ventricular rate 102 bpm
- Sinus rhythm
- PR interval 194 ms
- QRS axis (29°)
- QRS duration 128 ms
- R’ wave in aVR > 3 mm
- QTc 505 ms
- Sinus tachycardia
- Interventricular conduction delay – QRS duration > 100 ms in lead II
- Terminal R wave (R’) in aVR > 3 mm
What agents could potentially be responsible?