Figure 1 demonstrates what appears to be sinus tachycardia with left bundle-branch block. Closer evaluation of the rhythm strip reveals a P wave that is partially obscured by the T wave consistent with 2:1 atrioventricular (AV) conduction suggestive of infranodal disease (red arrows in Figure 2).
On further questioning, the patient reported owning a farm in southern Minnesota. He reported noting occasional ticks on his body but no known tick bites. Two weeks prior to his presentation he had a self-limited 4-day febrile illness with rigors.