Correspondence

Bradycardia

N Engl J Med 2000; 343:513-514August 17, 2000

Article

To the Editor:

The differential diagnosis of bradycardia reviewed recently by Mangrum and DiMarco (March 9 issue)1 should include Lyme carditis.2-4 Here, we describe a patient with Lyme carditis.

A 42-year-old patient presented with acute first-to-third-degree atrioventricular block. He reported having been bitten by a tick (Ixodes ricinus) six weeks before admission to the hospital. He had not had fever but had had unspecific discomfort of the knee and elbow joints and a sudden decrease in physical energy during the four weeks before admission. He had not had a syncopal event but had had attacks of dizziness. At admission, the results of clinical, radiologic, and echocardiographic examinations were normal. The electrocardiogram at admission showed a prolonged PR interval of 0.38 second with a normal ventricular response. The 24-hour electrocardiogram showed first-degree atrioventricular block and intermittent third-degree atrioventricular block. The lowest heart rate was 37 beats per minute. Because of this history, we immediately started antibiotic therapy with ceftriaxone, which was given for 20 days (4 g per day initially and 2 g per day at the end of treatment), with no pacemaker but with continuous monitoring during the first days of treatment. The effect of treatment on atrioventricular conduction was a steady decline in the PR interval from greater than 0.4 second initially to under 0.2 second by day 13 — an effect that persisted on day 31 (Figure 1Figure 1The Effects of Antibiotic Therapy on the PR Interval.). The patient was cured.

The results of microbiologic testing for Borrelia burgdorferi were as follows. The enzyme-linked immunosorbent assay for B. burgdorferi was positive for IgG antibodies (titer, 1:320) and negative for IgM antibodies. In the Western blot for IgG antibodies, the serum reacted with bands at 18, 60, and 88 kd. In the Western blot for IgM antibodies, reactions with bands at 41 kd and weak reactions with bands at 21 kd were noted. This pattern is characteristic of the postacute phase of the infection.

In patients such as the one we describe, Lyme carditis should be considered. Although it is rare, this condition can be treated effectively with antibiotics.

Wolfgang Mitlehner, M.D.
Turmstr. 21, 10559 Berlin, Germany

Wolfgang Bär, M.D., Ph.D.
Carl Thiem Klinikum, 03048 Cottbus, Germany

4 References

1. 1

   Mangrum JM, DiMarco JP. The evaluation and management of bradycardia. N Engl J Med 2000;342:703-709
   Full Text | Web of Science | Medline

2. 2

   Steere AC, Batsford WP, Weinberg M, et al. Lyme carditis: cardiac abnormalities of Lyme disease. Ann Intern Med 1980;93:8-16
   Web of Science | Medline

3. 3

   Steere AC. Lyme disease. N Engl J Med 1989;321:586-596
   Full Text | Web of Science | Medline

4. 4

   Cox J, Krajden M. Cardiovascular manifestations of Lyme disease. Am Heart J 1991;122:1449-1455
   CrossRef | Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: Mitlehner and Bär remind us that Lyme disease, an infectious cause of atrioventricular block, is increasing in frequency. Carditis occurs in about 10 percent of patients with Lyme disease, and transient atrioventricular block is a frequent cardiac manifestation. Fortunately, as was the case with the patient they describe, the period of heart block is usually self-limited, and permanent pacing is rarely required in patients with this disorder.

J. Michael Mangrum, M.D.
John P. DiMarco, M.D., Ph.D.
University of Virginia Health Sciences Center, Charlottesville, VA 22908