Scenаriо: Yоu аrrive оn scene to find а 72-year-old male, John Smith, sitting in a chair, pale and diaphoretic. He reports dizziness, chest discomfort, and a feeling of impending doom. His vital signs show a heart rate of 32 bpm, blood pressure of 80/50 mmHg, and an ECG confirms 3rd-degree (complete) heart block. En Route Phase: After initial intervention, remains hypotensive with a blood pressure of 70/40 mmHg despite initiating Dopamine at 5 mcg/kg/min. What is the next appropriate action?