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Lyme carditis most commonly manifests as atrioventricular (AV) block.
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Lyme carditis is readily treatable with antibiotic therapy and supportive care measures.
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Although temporary pacemaker placement may be needed for patients with Lyme carditis manifesting as high-grade second- or third-degree AV block with debilitating symptoms and/or hemodynamic instability, permanent pacemaker placement is not recommended.
Lyme Carditis
Section snippets
Key points
Epidemiology
Although Lyme disease is common in North America and Europe, affecting as many as 1 in 1000 people in certain American states and 1 in 300 people in parts of Southern Europe annually, its cardiac manifestations that predominantly include conduction disturbances affect only a small minority of patients.1, 2 Such conduction disturbances were first described in 1977, and in 1980 the term, Lyme carditis, was coined to describe the variety of cardiac abnormalities found in patients with Lyme disease.
Pathogenesis
Understanding of the pathogenesis of Lyme carditis has been obtained primarily from study of mouse models. After mice are inoculated with B burgdorferi, sacrificed murine hearts demonstrate peak inflammatory changes at 2 to 3 weeks. During the first month postinoculation, inflammatory infiltrates have been demonstrated within the connective tissue of the heart base, aortic root, atrial and ventricular epicardium, endocardium, myocardium, and perivascular spaces, with notable foci at the AV
Demonstration of myocardial involvement in humans
Pathologic features of Lyme carditis in humans have been described in small numbers of patients who have undergone myocardial biopsy or autopsy. In the few patients whose deaths were attributed to Lyme carditis, autopsies showed infiltration of the endocardium, myocardium, and pericardium with lymphocytes, plasma cells, and macrophages. Perivascular inflammation has been prominent in most cases reported within the United States, and interstitial infiltration and inflammation have been observed
Clinical manifestations
Although there is pathologic evidence of diffuse carditis in mouse models and case reports of myocardial injury on human biopsy specimens, a vast majority of Lyme carditis that come to clinical attention involve a fairly narrow spectrum of manifestations; these predominantly include derangements of cardiac conduction, including varying degrees of heart block (Box 1).36, 37 This array of clinical manifestations arises within a prescribed timeline after initial infection.
Usually, Lyme disease
Risk of developing carditis
Carditis is a rare occurrence after a diagnosis of Lyme disease has been made. In the era before antibiotic treatment of Lyme disease, 2 of 55 (4%) prospectively followed patients with EM manifested cardiac involvement during a mean duration of 6 years of follow-up. One patient developed Wenckebach rhythm and the other complete heart block. Both were symptomatic.3, 40
Although no study has ever proved that antibiotic therapy for Lyme disease prevents cardiac manifestations, in a study of 61
Conduction system disease
In a compilation of 875 Lyme disease cases reported to the CDC from 1983 to 1986 wherein information about cardiac manifestations was provided, 84 cases of cardiac involvement were reported, including 16 (19%) with conduction defects.5 Since that early case series, reporting guidelines have changed, such that currently only Lyme disease cases with associated second- or third-degree heart block are reported as having cardiovascular involvement for surveillance purposes.7
Because Lyme carditis is
Myopericarditis and valvular disease
Although myocardial inflammation is commonly seen on histopathologic analysis of cardiac tissue obtained via biopsy from patients with Lyme carditis, clinically apparent acute myocarditis is uncommon. Myocarditis was reported in only 8 of 84 (10%) cases reported to the CDC in a series from the mid-1980s.5 Some patients thought to have symptoms attributable to conduction disease have also been found to have transiently and reversibly decreased left ventricular cardiac function; symptomatic
Chronic dilated cardiomyopathy
Whether Lyme disease can cause chronic dilated cardiomyopathy (DCM) is controversial. In 1990, an Austrian group suggested a link between Lyme disease and idiopathic DCM after culturing B burgdorferi from a myocardial biopsy of a patient with idiopathic DCM and a positive Lyme serology.55 Spirochetes were also identified by silver staining of endomyocardial biopsies obtained by the same group from DCM patients with B burgdorferi seropositivity.56, 57, 58 This group also found that 19 of 72
Diagnosis
Establishing a diagnosis of Lyme carditis can be difficult, because serologic testing for Lyme disease is incompletely reliable for the diagnosis of early disease in the first few weeks after acquiring infection. Furthermore, evidence supporting a diagnosis of cardiac involvement may be nonspecific. As with all manifestations of Lyme disease, epidemiologic risk for acquisition of B burgdorferi infection is essential. If the person has not been to a Lyme disease–endemic area within the past
Treatment
On diagnosing Lyme carditis, a decision must be made regarding a need for inpatient hospitalization. Current guidelines recommend that any patient with cardiac symptoms, such as syncope, dyspnea, or chest pain; patients with first-degree heart block and a PR interval greater than or equal to 300 milliseconds; and patients with second- or third-degree heart block be admitted for continuous telemetry monitoring.50 The rationale for admitting such a broad range of patients, including some with
Prognosis
Lyme carditis has an excellent prognosis. In patients with third-degree heart block, the median time to improvement to first-degree heart block or normal sinus rhythm is 6 days (range 1–42 days).12 Persistent heart block has been described after 7 weeks and 1 year of follow-up but is exceedingly rare.31, 69 Acute, but transient, worsening after initiation of antibiotics has rarely been reported and is attributed to a Jarisch-Herxheimer–like reaction.48, 66
Although the prognosis of Lyme carditis
Summary
Lyme disease is a common disease that uncommonly affects the heart. Because of the rarity of this diagnosis, and given the frequent absence of other concurrent clinical manifestations of early Lyme disease, consideration of Lyme carditis demands a high level of suspicion when patients in endemic areas come to attention with cardiovascular symptoms and evidence of higher-order heart block. When present, a majority of cases manifest as AV block ranging from asymptomatic first-degree heart block
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2022, Infectious Disease Clinics of North AmericaCitation Excerpt :The paucity of data and studies surrounding risk factors for Lyme carditis presents further hurdles for preventing and understanding this complication of Lyme disease. Clinical observations of Lyme carditis consist of case reports and series, and one autopsy series.22 The information on pediatric patients is even more limited; the largest published cases series in children (n = 33) includes only 14 with advanced heart block.4
Disclosure Statement: None of the authors have anything to disclose.