A 68-year-old woman presents with an acute onset of confusion, shortness of breath, and diaphoresis. Her blood pressure is 72/50 mm Hg, her heart rate is slow and weak, and her respirations are increased and shallow. The ECG reveals a third-degree heart block at a rate of 38 beats/min. After placing the patient on high-flow oxygen, you should:

A) start an IV and administer 0.5 mg atropine.
B) obtain a 12-lead ECG to detect an acute myocardial infarction.
C) obtain vascular access and give a fluid bolus.
D) immediately attempt transcutaneous pacing.

Answer: D) immediately attempt transcutaneous pacing.