To Pace or Not to Pace
A 60-year-old patient who is a prior heavy smoker and actively receiving paclitaxel 40 mg intravenously weekly, carboplatin 210 mg intravenously weekly, and volumetric modulated arc radiotherapy (40 out of 60 Gy) to the right upper chest presented with fever of 100.5 following radiation therapy. She has a past medical history of stage 4 (T1 N2 M1) spindle cell lung cancer with prior gamma knife radiosurgery, asthma/chronic obstructive pulmonary disease, diabetes mellitus type 2, and major depression. She was hypotensive with systolic blood pressure in the 80s at the time. She was asymptomatic, not noting any palpitations, lightheadedness, or dizziness, though she was notably depressed and generally sedentary. No source of infection was identified. Active medications include oxycodone, prochlorperazine, duloxetine, levetiracetam, and clonazepam. Figure 1 shows the rhythm found upon placing on telemetry. Figure 2 shows stable electrocardiogram.
What is the cause of this patient's heart block, and what treatment does it warrant?