Case Presentation: A 60-year-old man with a history of nonverbal seizure disorder on lamotrigine presented to the Emergency Department, after being found down. The patient endorsed multiple episodes of syncope in the past 24 hours. Immediately preceding each episode, he felt an electric sensation on the left side of his head associated with what he described as a “breeze-like sensation.” In the ED, the patient continued to experience these atypical symptoms, and following the symptoms he reliably became bradycardic down to 20 beats per minute. An electrocardiogram between episodes showed sinus bradycardia with frequent premature atrial complexes, a constant PR interval of 206, and intermittent non-conducted P-waves, consistent with Mobitz type II heart block. Laboratory findings demonstrated normal electrolytes, lactate, lamotrigine level, and CP. He subsequently experienced two witnessed sinus pauses, which lasted eight seconds each. Both episodes were treated with 1 mg IV atropine following the event. It was notable that he endorsed a breeze-like sensation prior to every episode. The patient worked as a landscaper, and due to high-grade heart block and potential occupational exposure, the decision was made to empirically treat him for Lyme disease with ceftriaxone, 2 grams IV daily. He denied any recent tick exposures or new rashes or finding a tick. He was then admitted to the ICU and a transvenous pacing wire was placed. Lyme titers were later found to be positive for IgM antibodies. An echocardiogram was negative for underlying structural heart disease. Electrophysiology was consulted for consideration of pacemaker placement; however, this was deferred due to rapid improvement in the patient’s bradycardia. After four days of therapy with ceftriaxone his PR interval decreased to 170 and the heart block had resolved. He was prescribed a course of 30 days of intravenous ceftriaxone to complete therapy.
Discussion: Lyme disease is a systemic illness caused by the spirochete, Borrelia burgdorferi. Cardiac conduction defects and AV nodal blockade in particular are well-known possible complications of infection. In severe or untreated cases, AV nodal blockade can rapidly progress to third-degree heart block. The mainstay of treatment is antibiotic therapy (generally including 2nd or 3rd-generation cephalosporins, doxycycline, or amoxicillin), and can include temporary cardiac pacing in cases of life threatening illness. When indicated, temporary pacing is recommended over the placement of a permanent pacemaker. In hospitalized patients, therapy with intravenous ceftriaxone is recommended until clinical improvement, which is frequently defined as the resolution of high-grade heart block and shortening of the PR interval to less than 300, as these are the cardiac manifestations indicative of severe Lyme carditis (2, 3). Of note, these treatment guidelines are based primarily on expert opinion and very low-quality evidence.
Conclusions: We present a case of a patient who could predict when he was going to have a bradycardic event and sinus pause due to Lyme carditis, and have not found another such account describing a patient who could accurately predict the onset of bradycardia. We speculate that these “prodromal” or “early alert” symptoms may have been attributable either to an atypical manifestation of early parasympathetic activation or to other disease-related manifestations, as Lyme disease is known to additionally cause peripheral neuropathies as well as central nervous system infection.