The figure above shows a Warthin-Starry stain of cardiac tissue demonstrating Borrelia burgdorferi spirochetes in one of three patients whose death was associated with Lyme carditis during November 12-July 2013. Downloaded from MMWR Morb Mortal Wkly Rep. 2013 Dec 13;62(49):993-6.
Borrelia burgdorferi, the organism which causes Lyme disease, infects the heart in an estimated 1% of patients.[1] Lyme carditis is typically seen after an episode of the "summer flu" which may be the initial manifestation of infection. Symptoms of carditis, inflammation of the heart, tend to occur with the other manifestations of disease - joint pains, rash, brain fog or other neurologic symptoms. However in some patients a conduction defect - even complete heart block - may be the only manifestation of infection with the Borrelia spirochete.[2]
Common complaints when Borrelia infects the heart range from no symptoms at all to palpitations, to severe conduction abnormalities seen on EKG. There may be chest pain, heart dysfunction because of inflammation, pericardial effusion (fluid surrounding the heart), even congestive heart failure. The carditis is rarely fatal - although a few fatalities have been reported.[3], [4], [5]
It is thought that the chief abnormality lies within the conduction system of the heart as a direct effect of the Borrelia spirochete, since the conduction defect does not appear to be responsive to the usual pharmaceutical treatments for heart block. Temporary pacemakers may be needed in about 35% of cases, and almost all cases resolve within a few weeks, with the appropriate intravenous antibiotic therapy.[6], [7]
Lyme carditis, downloaded from the CDC website "What you need to know about Lyme carditis" 2/22/2014
Diagnosing Lyme carditis is just as difficult as diagnosing Lyme disease itself. When there is historical evidence of Lyme disease (EM rash, tick bit, arthritis, encephalitis or other manifestations of Lyme disease), then the diagnosis is much easier. A positive ELISA test is helpful, a positive Western Blot is helpful - but negative tests do not rule out the diagnosis. Measurement of IgG and IgM antibodies to Borrelia is helpful. Biopsy of the heart is not recommended, even though it might be diagnostic.
Antibiotic therapy is generally effective - as with other manifestations of Lyme disease - although the IDSA recommendations are almost certainly inadequate for treatment of this chronic condition. Steroid treatment is not recommended, as steroids may precipitate symptoms in joints or the central nervous system.
The good news is that people generally recover from Lyme carditis, as long as the Lyme disease and coinfections are treated.
[1]Fish AE, Pride YB, Pinto DS. Lyme Carditis. Infect Dis Clin N Am 22(2008):275-288.
[2]Kimball SA, Janson PA, LaRaia PJ. Complete heart block as the sole presentation of Lyme disease.Arch Intern Med. 1989 Aug;149(8):1897-8.
[3]N. R. Cary, B. Fox, D. J. Wright, S. J. Cutler, L. M. Shapiro, and A. A. Grace. Fatal Lyme carditis and endodermal heterotopia of the atrioventricular node.
Fatal Lyme carditis and endodermal heterotopia of the atrioventricular node.
Fatal Lyme carditis and endodermal heterotopia of the atrioventricular node.Postgrad Med J. 1990 February; 66(772): 134-136. PMCID: PMC2429516.
[4]Marcus LC, Steere AC, Duray PH, Anderson AE, Mahoney EB. Fatal pancarditis in a patient with coexistent Lyme disease and babesiosis. Demonstration of spirochetes in the myocardium.Ann Intern Med. 1985 Sep;103(3):374-6.
[5]Centers for Disease Control and Prevention (CDC). Three sudden cardiac deaths associated with Lyme carditis – United States, November 2012-July 2013.MMWR Morb Mortal Wkly Rep. 2013 Dec 13;62(49):993-6.
[6]van der Linde MR. Lyme carditis: clinical characteristics of 105 cases.Scand J Infect Dis Suppl. 1991;77:81-4.
[7]van der Linde MR1, Crijns HJ, de Koning J, Hoogkamp-Korstanje JA, de Graaf JJ, Piers DA, van der Galiën A, Lie KI. Range of atrioventricular conduction disturbances in Lyme borreliosis: a report of four cases and review of other published reports.Br Heart J. 1990 Mar;63(3):162-8.