Lyme Carditis Case Without Heart Block: Missed Early Signs

Lyme carditis is often associated with heart block, but cardiac involvement can present in other ways. A case from Cape Cod highlights how Lyme disease may affect the heart even without classic conduction abnormalities.

This raises an important question: can Lyme carditis present without heart block? Clinical findings suggest that broader cardiac manifestations should be considered, particularly in patients with recent tick exposure.

“Three weeks after a vacation in Cape Cod, the patient awoke during the night and later found himself on the bathroom floor without recalling any warning symptoms,” according to Patel from Brown University.

Initial Presentation and Missed Diagnosis

In the weeks following the syncopal episode, the patient reported a sharp decline in exercise tolerance.

Six weeks prior to admission, he had developed an oval-shaped rash behind his knee while vacationing in Cape Cod. The rash was treated with cephalexin for presumed cellulitis.

Diagnosis of Lyme Carditis

Lyme disease was considered during cardiac evaluation. The authors suggested that the presentation may have involved microvascular inflammation affecting cardiac function.

The patient was diagnosed with Lyme disease and treated with intravenous ceftriaxone, followed by a 21-day course of oral doxycycline.

He also required treatment with furosemide for heart failure.

Clinical Implications

This case highlights the importance of recognizing early Lyme disease and selecting appropriate antibiotic therapy.

Cephalexin is not effective for Lyme disease and may delay appropriate treatment when early Lyme is misidentified as cellulitis.

Clinicians may consider Lyme disease in patients with cardiac symptoms, syncope, or reduced exercise tolerance following possible tick exposure, even in the absence of heart block.

Clinical Perspective

This case illustrates that Lyme carditis may present with a broader range of cardiac findings than traditionally recognized.

Patients may benefit from review of Lyme disease symptoms, understanding testing limitations, and awareness of coinfections in complex presentations.

References

1. Patel LD, Schachne JS. Lyme carditis case involving conduction system and mitral valve. R I Med J. 2017.
2. Nowakowski J et al. Failure of cephalexin for Lyme disease. Arch Fam Med. 2000.

Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention