Final answer:
The appropriate therapy indicated in this scenario is to initiate external cardiac pacing.
Step-by-step explanation:
In this scenario, the patient has sinus bradycardia with a heart rate (HR) of 36 bpm. Atropine has been administered without success, and a transcutaneous pacemaker has failed to capture. The patient is confused and has a blood pressure (BP) of 88/56 mmHg. Given these findings, the most appropriate therapy is to initiate external cardiac pacing.