From a Tick Bite to Av Block

Introduction Lyme carditis, a late-stage Lyme disease manifestation caused by Borrelia burgdorferi, commonly presents as atrioventricular block (AVB), ranging from first-degree to complete. Symptoms may vary from palpitations and dizziness to syncope or, in severe cases, heart failure [1]. Case Presentation A 65-year-old man presented with general weakness, shortness of breath during mild physical exertion, and a slow pulse. A few weeks earlier, he experienced joint pain and reported multiple tick bites within a month. ECG revealed III* AVB with a heart rate of 30 bpm, the patient was urgently hospitalized at the LSMU KK Cardiology Clinic. Due to significant bradycardia unresponsive to salbutamol, a temporary right ventricular pacemaker was implanted. Tests revealed leukocytosis, CRP of 6.4 mg/L, echocardiography findings of grade II MV regurgitation, concentric LV remodeling, and an EF of 50%. Suspected Lyme carditis resulted in specialist referral, immunological testing, and IV ceftriaxone initiation. The patient’s heart was monitored via telemetry throughout the hospital stay. After 5 days, positive IgG and IgM antibodies against Borrelia burgdorferi were confirmed, and a 21-day antibiotic course was suggested. On day 18, Holter monitoring showed sinus rhythm with a minimum HR of 41 bpm, an average of 53 bpm, and a maximum of 93 bpm, with episodes of II*, Mobitz type I AVB and no hemodynamically significant pauses. After 2 days, the temporary pacemaker was removed, the IV antibiotic treatment was completed, and the patient was discharged with outpatient follow-up. Second-degree, Mobitz type I AVB Discussion Bradycardia requires cardiac monitoring, as it may progress from first-degree to complete AVB or asystole. In Lyme carditis, up to 30% of patients may need temporary and, rarely, permanent pacemaker implantation [2]. Conclusions Lyme carditis is a severe complication of Lyme disease that can cause varying degrees of AVB. Early antibiotic treatment often leads to AVB regression within the first week of therapy, though some cases may require temporary pacemaker implantation.