Can Lyme Disease Affect the Heart in Ways Other Than Heart Block?
Heart block is the classic cardiac manifestation of Lyme disease
Arrhythmias, myocarditis, and pericarditis have also been reported
A 2026 review describes a broader spectrum of cardiovascular involvement
Can Lyme disease affect the heart in ways other than heart block? Yes. Atrioventricular (AV) block is the best-recognized cardiac manifestation of Lyme disease, but it is not the only cardiovascular problem that has been reported.
A 2026 review of 30 studies found that the published literature also includes arrhythmias, myocarditis, pericarditis, myopericarditis, valvular endocarditis, aortitis, and vasculitis in patients with Lyme disease.1
The evidence is strongest for conduction abnormalities such as heart block associated with Lyme disease. Evidence for many of the less common cardiac manifestations is much more limited and often comes from individual case reports or small case series.
This distinction is important. The review demonstrates that the reported cardiovascular spectrum of Lyme disease extends beyond heart block, but it does not establish that these uncommon complications occur frequently in patients with Lyme disease.
What Heart Problems Have Been Reported With Lyme Disease?
Cortes Islas and colleagues reviewed literature published between January 2000 and July 2025 describing cardiovascular involvement in patients with confirmed Lyme disease.1
The authors identified several categories of cardiovascular manifestations:
- Atrioventricular conduction abnormalities, including complete heart block
- Atrial and ventricular arrhythmias
- Myocarditis
- Pericarditis and myopericarditis
- Pericardial effusion
- Valvular endocarditis
- Aortitis
- Vasculitis
These conditions do not have equal levels of supporting evidence. AV conduction abnormalities dominate the clinical literature, whereas conditions such as Lyme-associated endocarditis, valvular disease, and aortitis are exceedingly rare and have been described primarily in isolated reports.
Heart Block Remains the Classic Manifestation of Lyme Carditis
AV block was the most consistently reported cardiovascular manifestation in the 2026 review.1
The severity can range from relatively minor conduction abnormalities to complete heart block associated with bradycardia, dizziness, fainting, or hemodynamic instability.
One unusual characteristic of Lyme-associated heart block is its potential reversibility. High-grade AV block may require temporary pacing while antimicrobial treatment takes effect, but the review found that permanent pacemaker implantation was rarely necessary because conduction abnormalities often improved with treatment.1
This differs from many other causes of complete heart block, where permanent pacing may ultimately be required.
Can Lyme Disease Cause Abnormal Heart Rhythms?
Yes. The cardiovascular literature reviewed by Cortes Islas and colleagues includes several rhythm abnormalities beyond AV block.1
Reported arrhythmias include atrial fibrillation, supraventricular tachyarrhythmias, ventricular tachyarrhythmias, sinus node dysfunction, bradycardia-tachycardia episodes, and, in rare reports, ventricular fibrillation.
Patients with cardiac involvement may experience palpitations, dizziness, fainting, shortness of breath, or chest discomfort. Some conduction or rhythm abnormalities may also be discovered on an EKG even when chest pain is absent.
These symptoms are not specific to Lyme disease. Numerous cardiac and noncardiac conditions can cause palpitations, dizziness, and abnormal heart rhythms, making appropriate medical evaluation important.
Can Lyme Disease Cause Myocarditis?
Myocarditis is inflammation of the heart muscle. It is an uncommon but documented manifestation within the cardiovascular spectrum of Lyme disease.1
Lyme myocarditis can produce electrocardiographic abnormalities, ventricular dysfunction, arrhythmias, and symptoms that may resemble other cardiac conditions.
In some reported cases, myocarditis or myopericarditis has produced chest pain and other findings that resemble an acute coronary syndrome. This can make the initial presentation look more like a heart attack than a tick-borne infection.
Cardiac magnetic resonance imaging may help identify myocardial inflammation in selected patients. However, the diagnosis must be interpreted in the overall clinical context because myocarditis has numerous infectious, inflammatory, immune-mediated, and other potential causes.
Can Lyme Disease Cause Pericarditis?
Pericarditis, inflammation of the sac surrounding the heart, has also been reported with Lyme disease, although it appears considerably less common than conduction abnormalities.1
Some patients have been described as having myopericarditis, meaning that inflammation involves both the heart muscle and the pericardium.
Possible findings include chest pain, electrocardiographic changes, pericardial inflammation on cardiac imaging, and occasionally pericardial effusion, an accumulation of fluid around the heart.
As with myocarditis, a diagnosis of Lyme-associated pericarditis requires clinical judgment because pericarditis has many possible causes and the evidence specifically connecting it with Lyme disease consists largely of uncommon reported cases.
Can Lyme Disease Affect the Heart Valves?
Valvular involvement is among the rarest cardiovascular manifestations discussed in the review.1
A small number of reports have described culture-negative endocarditis in which Borrelia burgdorferi DNA was detected in surgically removed heart valve tissue.
These cases are scientifically interesting because they suggest that the cardiovascular manifestations associated with Lyme disease may extend beyond the conduction system, myocardium, and pericardium.
However, the authors emphasize the need for considerable caution. Much of the evidence for Lyme-associated endocarditis consists of isolated cases, and some reports relied primarily on serology without direct microbiological confirmation in the affected valve tissue.1
Therefore, valvular disease should not automatically be attributed to Lyme disease simply because a patient has positive Lyme antibodies or a previous history of Lyme disease.
What About Aortitis and Vasculitis?
Aortitis and vasculitis are also included within the broader cardiovascular spectrum described in the literature, but both are rare.1
Aortitis involves inflammation of the wall of the aorta. Reports potentially associated with Lyme disease are uncommon and do not provide enough evidence to determine how often this occurs.
Vascular inflammation has also been reported in Lyme neuroborreliosis, including rare cases associated with cerebral ischemia and other cerebrovascular complications.
These unusual manifestations should be viewed differently from AV block. They broaden our understanding of what has been reported in association with Lyme disease, but the evidence is much more limited.
Can Lyme Cardiac Symptoms Occur Without Chest Pain?
Yes. Cardiac involvement does not necessarily produce chest pain.
Depending on the part of the heart affected, symptoms may include:
- Palpitations
- Dizziness or lightheadedness
- Fainting
- Shortness of breath
- Unusual fatigue
- Slow heart rate
- Rapid or irregular heartbeat
- Chest discomfort or chest pain
For example, dizziness can sometimes be a cardiac symptom when Lyme disease affects conduction or heart rhythm. At the same time, dizziness is common and can arise from many noncardiac causes.
The nature of the symptoms, physical examination, EKG findings, cardiac monitoring, laboratory testing, and imaging may all contribute to determining whether the heart is involved.
How Is Cardiac Involvement From Lyme Disease Evaluated?
The 2026 review emphasizes that diagnosis relies on a combination of clinical suspicion, epidemiologic history, Lyme testing, electrocardiographic monitoring, and cardiac imaging rather than any single finding.1
An EKG is particularly important when conduction disease or an arrhythmia is suspected. Telemetry or ambulatory monitoring may be useful when rhythm abnormalities are intermittent.
Echocardiography can assess ventricular function, valve abnormalities, and pericardial effusion. However, a normal echocardiogram does not necessarily exclude Lyme carditis, particularly when the primary problem involves the electrical conduction system rather than heart structure.
Cardiac MRI may provide additional information when myocarditis or pericarditis is suspected.
Are These Heart Problems Usually Reversible?
Many of the cardiac abnormalities described in Lyme disease improve with appropriate antimicrobial treatment, particularly conduction abnormalities.1
The review found generally favorable outcomes when cardiac involvement was recognized and treated promptly. Temporary pacing was required in some patients with severe conduction disease, but permanent pacemakers were rarely necessary.
That favorable pattern should not minimize the seriousness of Lyme carditis. High-grade heart block and significant arrhythmias can become medical emergencies and may require hospitalization, continuous cardiac monitoring, intravenous antibiotics, and temporary pacing.
What Does the 2026 Review Add?
The most useful contribution of this review is not the discovery of a new cardiac complication. Instead, it brings together the scattered literature showing the breadth of cardiovascular manifestations reported in Lyme disease.1
Heart block remains the dominant and best-established manifestation, but the literature also contains reports involving the heart rhythm, myocardium, pericardium, valves, aorta, and blood vessels.
There is an important limitation. The authors conducted a narrative review rather than a formal systematic review, and most of the underlying evidence consisted of case reports and small case series. No formal risk-of-bias or GRADE assessment was performed.1
Therefore, the relative frequency of different manifestations in the published literature should not be interpreted as their prevalence among patients with Lyme disease.
Frequently Asked Questions
Is heart block the only heart problem caused by Lyme disease?
No. Heart block is the classic and best-recognized manifestation of Lyme carditis, but arrhythmias, myocarditis, pericarditis, myopericarditis, pericardial effusion, and much rarer valvular and vascular complications have also been reported.
Can Lyme disease cause myocarditis?
Yes. Myocarditis has been reported as an uncommon manifestation of Lyme disease. It may be associated with abnormal EKG findings, arrhythmias, ventricular dysfunction, or symptoms resembling other cardiac conditions.
Can Lyme disease cause pericarditis?
Yes. Pericarditis and myopericarditis have been reported with Lyme disease, although they appear to be considerably less common than conduction abnormalities such as AV block.
Can Lyme disease cause an irregular heartbeat?
Yes. Atrial and ventricular arrhythmias, sinus node dysfunction, and other rhythm disturbances have been described in patients with Lyme disease. However, abnormal heart rhythms have many possible causes and require appropriate evaluation.
Are Lyme-related heart problems reversible?
Many reported cardiac manifestations improve with antimicrobial treatment, particularly AV conduction abnormalities. Severe heart block may temporarily require pacing, but permanent pacemaker implantation is often avoidable when the conduction abnormality resolves.
Clinical Takeaway
Heart block remains the most recognizable and best-supported cardiac manifestation of Lyme disease, but it does not represent the entire cardiovascular spectrum.
The 2026 review identified published reports of arrhythmias, myocarditis, pericarditis, myopericarditis, pericardial effusion, valvular endocarditis, aortitis, and vasculitis. Evidence for the rarer manifestations is substantially weaker because much of it comes from individual case reports and small case series.
Clinically, symptoms such as palpitations, unexplained dizziness, fainting, shortness of breath, or chest pain in a patient with possible Lyme disease may warrant consideration of cardiac involvement along with other potential causes.
Lyme disease can affect more than the heart’s electrical conduction system, but the strength of evidence varies considerably across the different reported cardiovascular manifestations.
Related Articles
These articles explore additional aspects of cardiac involvement and Lyme disease:
Can Lyme Disease Cause Pericarditis? Symptoms, Cases and Treatment
Can Lyme Disease Cause an Abnormal EKG Without Chest Pain?
Can Lyme Disease Mimic a Heart Attack? Understanding Lyme Carditis
References
- Cortes Islas LA, Bartolo Gomez PM, Cuevas Obispo ND, Xicohtencatl Muñoz A, Lopez Lucero LYL, Ramirez Hinojosa JP. Cardiovascular manifestations documented in patients with Lyme disease: Clinical presentation, management strategies, and outcomes. Infect Dis Rep. 2026;18(3):40. doi:10.3390/idr18030040.
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
