A 75-year-old man presents with syncope and a heart rate of 32 bpm. ECG shows complete heart block with a broad-complex escape rhythm. He is hypotensive (BP 70/45) and diaphoretic. IV atropine 500 mcg is given with no response. The transcutaneous pacing pads are applied but fail to capture. What is the next step according to Resuscitation Council UK peri-arrest bradycardia algorithm?