Can Lyme Disease Cause AFib? Lyme Carditis and Atrial Fibrillation
AFib may rarely occur with Lyme carditis
Heart rhythm changes can precede classic findings
Early recognition may improve outcomes
Patients frequently ask whether Lyme disease can cause atrial fibrillation (AFib). Lyme carditis is more commonly associated with atrioventricular (AV) block, but rare presentations involving atrial fibrillation have also been described.
Because AFib is not typically considered a classic presentation of Lyme carditis, diagnosis may be delayed—particularly in younger patients without obvious cardiac risk factors.
Can Lyme Disease Cause AFib?
Possibly. Although uncommon, atrial fibrillation has been reported as an early presentation of Lyme carditis.
A case report published in BMJ Case Reports described a 23-year-old man with sudden palpitations whose ECG demonstrated atrial fibrillation with a mildly dilated left atrium.
The patient did not recall a tick bite or rash. Because AFib is not a classic presentation of Lyme carditis, clinicians initially considered Lyme disease less likely.
When AFib Progressed to Heart Block
Four days later, the patient returned to the hospital.
Telemetry and ECG revealed Mobitz II AV block alternating with intermittent complete heart block.
Clinicians treated him empirically with intravenous ceftriaxone before confirmatory Lyme testing returned positive.
Within 48 hours, symptoms improved and one month later his heart rhythm normalized after treatment.
Learn more about complete heart block in Lyme carditis.
Why Lyme Carditis Can Be Missed
Lyme carditis most commonly presents with conduction abnormalities rather than atrial fibrillation.
Because AFib is common and Lyme carditis is relatively uncommon, clinicians may initially pursue more typical explanations for arrhythmia.
Young patients with new arrhythmias, outdoor exposure, or symptoms consistent with Lyme disease may warrant broader evaluation.
Diagnostic delays remain common when cardiac symptoms appear before classic Lyme findings.
Learn more about delayed Lyme disease diagnosis.
Does Lyme Carditis Show Up on ECG?
Yes. ECG abnormalities are frequently present in Lyme carditis and may evolve rapidly over time.
- First-degree AV block
- Mobitz I AV block
- Mobitz II AV block
- Complete heart block
- Atrial fibrillation (rare)
- Other supraventricular arrhythmias
Repeat ECG monitoring may be important when suspicion remains high because rhythm disturbances can change quickly.
Frequently Asked Questions
Can Lyme disease cause AFib?
Rarely. AFib has been described in Lyme carditis, although AV block remains more common.
Can a tick bite cause AFib?
A tick bite itself does not cause AFib, but tick-borne infections such as Lyme disease may occasionally contribute to cardiac rhythm abnormalities.
Does Lyme carditis show up on ECG?
Yes. ECG abnormalities commonly occur in Lyme carditis and may include AV block, conduction abnormalities, or rarely atrial fibrillation.
Is AFib a common symptom of Lyme carditis?
No. AV conduction abnormalities remain the more typical presentation of Lyme carditis.
Can Lyme carditis improve after antibiotics?
Many patients improve with appropriate antibiotic treatment, though monitoring may still be necessary.
Clinical Takeaway
Lyme carditis usually presents with conduction abnormalities, but rare cases of atrial fibrillation have been described.
Young patients with unexplained arrhythmias, outdoor exposure, or evolving ECG abnormalities may warrant evaluation for Lyme disease.
Related Articles
These related articles explore cardiac manifestations, diagnostic delays, and overlapping presentations of Lyme disease.
5 things to know about Lyme carditis
Cardiac problems in Lyme disease
When Lyme disease mimics a heart attack
Lyme disease symptoms guide
Recovery from Lyme disease
References
- Kostić T, Momčilović S, Perišić ZD, et al. Manifestations of Lyme carditis. Int J Cardiol. 2017;232:24-32.
- Shabbir MA, Saad Shaukat MH, Arshad MH, Sacco J. Lyme carditis presenting as atrial fibrillation in a healthy young male. BMJ Case Rep. 2019;12(6).
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
Drs here don’t seem to think Lyme can cause Afib and won’t treat the Afib. I got Afib the same time I got Lyme, I was treated for Lyme but Afib persists, you have any ideas?
All I have been able to to do for my patients is to be sure their Lyme disease is successfully treated.
So, in your opinion no link between Lyme and Afib ?
I published the blog to encourage others work whether to add a tick borne illness to the long list of causes of atrial fibrillation. We do know that tick borne diseases can lead early to a electrical disturbance called heart block.
Lyme patient first 1998 with classic bulls eye rash over R thigh and No subsequent A-fib. Chronic Fatigue developed quickly afterwards. No antibiotic treatment ONLY large doses of natural supplements from Standard Process.
Exposure limited my competitive endurance athletic endeavors limiting my ability to train and perform. All hopes for return to high level competition slowly faded away.
Lyme exposure again 12 years later in June 2010 with classic Bulls eye rash over belly button and immediate horrible weakness and fatigue lasting 4-6 weeks. No serious Antibiotic treatment except 1 week Doxycycline orally but no significant progress. Large dosage of supplements again Now from PRL – Premier Research Labs with slow steady improvement over 6 weeks. Afib development about 4-5 months later for a few episodes during strenuous exercise training lasting about 4-5 hours each episode. Paroxysmal Afib to follow with episodes about 75% of the time with strenuous exercise. No traditional treatment.
1 year later went to strict Vegan diet with no Oils and no animal products and No nuts and seeds following Dr Caldwell Essylstein recommendations as per his best selling book Reversing Heart Disease.
4 weeks later Afib episodes stop for 3 months and I make mistake of returning to animal food consumption and quick return of paroxysmal Afib and now persistent Afib for past 5 years.
Vegan diet tried past 3 years off and with less and less changes in Afib episodes but good changes in cholesterol from Keto carnivore diet from 300 to 175. Elevated liver enzymes and renal enzymes with Keto carnivore diet. Return to normal levels with Vegan diet but now no improvement with consistent persistent Afib.
Desire to now focus upon treating my Afib in my blood and heart tissue to see if persistent Afib will change. Any natural remedy suggestions greatly appreciated.
There are so many factors related to atrial fibrillation. I was surprised that you did not try antibiotics for more than a week.