Lyme carditis with isolated left bundle branch block and myocarditis successfully treated with oral doxycycline

Area of Science:

• Cardiology
• Infectious Diseases
• Electrophysiology

Background:

• Lyme disease, a tick-borne illness, can affect the heart, causing Lyme carditis.
• Cardiac manifestations range from conduction abnormalities like heart block to myocarditis.
• Atrioventricular conduction disturbances are the most frequent cardiac findings in Lyme disease.

Purpose of the Study:

• To report a rare case of Lyme carditis presenting as isolated left bundle branch block (LBBB) in a young male.
• To highlight the diagnostic and therapeutic considerations for Lyme carditis with unusual electrophysiological findings.
• To illustrate the successful management and rapid resolution of LBBB and myocarditis with oral antibiotics.

Main Methods:

• Case report of a young male diagnosed with Lyme disease.
• Clinical evaluation including electrocardiography (ECG) to assess cardiac involvement.
• Echocardiography and laboratory tests to rule out other causes of myocarditis and LBBB.
• Treatment with oral doxycycline and monitoring of clinical and electrophysiological recovery.

Main Results:

• The patient presented with isolated left bundle branch block (LBBB) as the primary manifestation of Lyme carditis.
• Mild Lyme myocarditis was also diagnosed.
• The patient showed rapid and complete resolution of LBBB and myocarditis following treatment with oral doxycycline.
• No recurrence or long-term sequelae were observed.

Conclusions:

• Isolated left bundle branch block (LBBB) can be a rare but significant manifestation of Lyme carditis.
• Prompt diagnosis and treatment with oral antibiotics like doxycycline are effective in managing Lyme carditis, including conduction abnormalities and myocarditis.
• This case underscores the importance of considering Lyme disease in the differential diagnosis of new-onset LBBB, particularly in endemic areas.