The aim of this case report is to present a patient with Lyme carditis and erythema migrans complicated with third-degree atrioventricular (AV) block and the need for pacemaker implantation. A 20-year-old patient comes to the hospital because of syncope. A few days earlier, he had chest pains with an irregular heartbeat. Upon arrival, the heart rate is 30 beats per minute. The electrocardiogram (ECG) shows AV block of the third degree with asystolic pauses. In laboratory findings, leukocytosis (20x109) and C-reactive protein (10.8 mg/L). A transcutaneous temporary external pacemaker was placed. Anamnestic information is obtained about a tick bite and migrating erythema at the site of the bite one month before arrival at the hospital. Enzyme immunoassay was positive for Borrelia burgdorferi. Ceftriaxone is introduced into the treatment. Despite therapy, the patient has persistent symptomatic AV block of the third degree with presyncope and syncope, which is why a permanent two-chamber pacemaker is implanted. He was discharged from the hospital in a cardiac stable condition. At the follow-up after one year, he was symptom-free, there was no AV block in the ECG, and 0.1% ventricular stimulation was recorded in the pacemaker's memory. We conclude that third-degree AV block caused by a tick bite, complicated by Borrelia burgdorferi infection with erythema migrans and carditis, although in most cases it passes spontaneously, sometimes, if presyncope and syncope are present, along with temporary electrostimulation of the heart, it requires permanent electrostimulation of the heart.