Lyme Carditis Symptoms: When Heart Block Is the Only Clue
No rash.
No joint pain.
Only heart block.
Lyme carditis symptoms can be difficult to recognize when patients do not have the classic signs of Lyme disease.
In some cases, an abnormal heart rhythm may be the only clue.
This case highlights a 70-year-old man who presented without a rash, arthritis, or other typical Lyme symptoms—but was ultimately diagnosed with Lyme carditis.
What Are Lyme Carditis Symptoms?
Lyme carditis can affect the heart’s electrical system.
Symptoms may include:
- Shortness of breath
- Lightheadedness
- Fainting or near-fainting
- Chest discomfort
- Palpitations
- Fatigue
- Bradycardia
- AV block
But Lyme carditis may occur without a rash or joint pain.
Atypical Lyme Carditis Without Classic Lyme Symptoms
The authors describe a 70-year-old man who presented to the hospital with progressive orthopnea and shortness of breath with exertion.
He had a history of hypertension and calcific aortic stenosis.
At first, clinicians considered several possible explanations, including anemia, kidney disease, congestive heart failure, worsening aortic stenosis, and pneumonia.
Lyme disease was not obvious from the initial presentation.
Heart Block Was the Key Finding
The patient’s EKG showed bradycardia with a heart rate in the mid-40s and a first-degree AV block.
The case report later described Lyme disease presenting with a second-degree Mobitz type 1 AV block.
This is the key diagnostic point: Lyme carditis can present primarily as AV block.
In endemic areas, new heart block should prompt consideration of Lyme disease—even when other Lyme symptoms are absent.
Why Lyme Carditis Can Be Missed
Lyme carditis is often missed because the symptoms can look like other heart or lung problems.
Shortness of breath, fatigue, and abnormal heart rhythm may be attributed to:
- Congestive heart failure
- Aortic stenosis
- Pneumonia
- Anemia
- Kidney disease
- Age-related cardiac disease
When a patient has no rash, no arthritis, and no recalled tick bite, Lyme disease may not be considered early.
How the Diagnosis Was Made
Because the patient lived in a Lyme-endemic region and had unexplained conduction abnormalities, clinicians ordered a tick-borne disease panel.
The Lyme disease test was positive.
This changed the direction of the diagnosis.
The patient was treated with IV Rocephin and oral doxycycline.
His symptoms resolved, and his EKG returned to normal sinus rhythm without AV block.
Lyme Carditis Without Rash or Arthritis
Can Lyme carditis occur without rash or arthritis?
Yes. Lyme carditis may occur without the classic erythema migrans rash, joint swelling, or typical flu-like Lyme symptoms.
In this case, the heart rhythm abnormality was the main clue.
This is why Lyme disease should remain in the differential diagnosis for unexplained AV block in endemic regions.
Clinical Takeaway
Lyme carditis symptoms may be subtle, atypical, or mistaken for other cardiac conditions.
New AV block, bradycardia, or unexplained shortness of breath in a Lyme-endemic area should raise suspicion for Lyme carditis.
Early recognition matters because treatment can lead to resolution of conduction abnormalities and may help prevent long-term complications.
Related Articles
- Pacemakers for Lyme carditis
- Successful removal of pacemakers in patients with Lyme carditis
- Three deaths associated with Lyme carditis
References
- Najam, U. S., & Sheikh, A. (2023). An atypical case of Lyme disease presenting with Lyme carditis. Cureus, 15(3), e35907. https://doi.org/10.7759/cureus.35907
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
