Could there be subclinical cardiac involvement in early Lyme disease in children?

In an earlier study by Woolf and colleagues, nearly 1 in 5 children (19.6%) children with an erythema migrans (EM) rash or a positive two-tier Lyme serology had EKG evidence of carditis. Twenty-four of the children had atrioventricular (11.2%). Their study did not report troponin levels.¹

High-sensitivity cardiac troponin assays have been used to identify patients at high risk of cardiovascular and non-cardiovascular events.² The authors identified pneumonia, an infective exacerbation of chronic obstructive pulmonary disease, and sepsis as causes of noncardiovascular events.

Lewandrowski and colleagues looked at high-sensitivity troponin T in 41 individuals with early Lyme disease.³ All individuals presenting in the summer of 2015 met the Centers for Disease Control and Prevention (CDC) surveillance case definition of EM.

“One patient had a value greater than the cutoff used for acute myocardial infarction,” wrote the authors.³ Another five patients had high-sensitivity troponin T values significantly above the expected values for their sex (p<0.0001).

There are many possible explanations for increased high-sensitivity troponin T values in different patients in the absence of acute cardiac damage. “cTn (cardiac troponin assay) is commonly elevated in acute non-ACS conditions, as well as in chronic diseases,” wrote Park and colleagues. They added, “It is unclear why these elevations occur; yet they cannot be ignored as cTn levels in chronically unwell patients are directly correlated to prognosis.”4

“Our results raise the possibility that subclinical cardiac involvement may be more common in ELD than previously recognized,” wrote the authors. They added, further studies will be necessary to elucidate the significance of this finding.”

Lyme carditis

Lyme carditis is uncommon. Nevertheless, Kannangara and colleagues summarized the growing list of cardiac problems in Lyme disease, as described in the medical literature:

• First-degree heart block
• Wenckebach phenomenon (Mobitz type I)
• Mobitz type II
• Complete Heart block / High degree AV block
• Bundle branch block
• Sinus arrest / Sinus pauses
• Supraventricular tachycardia
• Atrial fibrillation
• Junctional tachycardia
• Fascicular tachycardia
• Ventricular tachycardia
• Ventricular flutter
• Bradycardia
• Narrow QRS escape rhythm
• Prolonged QT
• ST depression / T inversion
• ST elevation
• Asystole
• History of Wolf Parkinson White Syndrome. In a case of sudden death due to LC (Lyme Carditis).