A man in his 80s presented with weakness, fever, and chills of 1 week’s duration. His medical history was significant for severe aortic stenosis, heart failure with preserved ejection fraction, and end-stage renal disease requiring hemodialysis. His physical examination was unremarkable except for a hyperdynamic precordium, late peaking grade 3/6 ejection systolic murmur best auscultated over the aortic area, and pulsus parvus et tardus. Results from his laboratory tests were significant for a leukocyte count of 17 600/µL (17.6 × 109/L), a hemoglobin level of 11.8 g/dL (118 g/L), a platelet count of 97 × 103/µL (97 × 109/L), and a troponin level of 2.46 ng/mL. No electrolyte abnormalities were noted. Results from a urinalysis were negative for infection. An electrocardiogram (ECG) was performed (Figure 1).