Lyme Disease and the Heart

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Lyme Disease and the Heart

 

Cardiac manifestations of Lyme disease are relatively uncommon and

difficult to diagnose. According to Kornelia Keszler, MD,[5] of Yale University

School of Medicine, the most readily recognized feature of cardiac involvement

has been various degrees of heart block on ECG, which usually responds to

antibiotic therapy.

Typical complaints of Lyme disease patients with cardiac involvement are

chest pain, mild to moderate exertional dyspnea, and palpitations. (However,

these symptoms also may be due to neuropsychiatric problems and

musculoskeletal infection, so testing is important.) To evaluate such patients,

cardiac testing should include thallium stress electrocardiography (ECG) and

coronary angiography.

 

What does cardiac infection look like, and where are the organisms

localized? Stanek and colleagues[6] found thickening of the walls of small

endomysial vessels and infiltration by mononuclear cells. In murine studies,

Pachner and colleagues[7] found 3 predominant locations for B burgdorferi in

the

heart. In mice infected for less than a month, spirochetes could be found

mostly around blood vessels. By contrast, for longer infection periods, B

burgdorferi could also be seen in cardiac myocytes, often surrounded by

clear areas. B burgdorferi were also commonly found among collagen fibers.

 

Based on her series of cases and a review of the literature, Dr. Keszler

drew the following conclusions. Thallium imaging typically reveals diffuse

and patchy uptake of isotope in the myocardium, probably indicating

involvement of the small vessels of the heart. Patients generally experience

decreased exertional tolerance, as exhibited by a rapid increase in heart rate,

but there is no ECG evidence of ischemia to account for the decreased

tolerance. A variety of arrhythmias are seen, both ventricular and

supraventricular, and are more common than heart block. At this time, it is not

known

whether treatment of Lyme disease will alter the thallium imaging. However,

one study has found that cardiac abnormalities do not persist in patients

treated for Lyme disease

 

_http://www.medscape.com/viewarticle/418440_

(http://www.medscape.com/viewarticle/418440)