Autonomic and cardiac symptoms are among the most alarming in tick-borne illness — and the most likely to send someone through a long cardiac investigation that resolves nothing. When the ECG, echo, and Holter come back normal, the symptoms do not disappear. They are still there. Understanding why requires a different frame.
This page is a focused introduction to this cluster. It is not a diagnosis. It is context for a conversation you may need to have.
What you need to understand quickly
Standard cardiac investigations are designed to find structural problems — damaged muscle, blocked arteries, valve disease. They are not designed to find dysautonomia or regulatory dysrhythmia caused by systemic infection. Normal results mean the structure is intact. They do not mean the regulation is intact.
"My heart tests are normal, so this must be anxiety." Anxiety is a common misattribution for autonomic symptoms in tick-borne illness. The ANS dysregulation looks similar on the surface. The mechanism — and the treatment path — is entirely different.
Ask: "Does my body struggle to regulate itself — heart rate, temperature, blood pressure, energy — in ways that feel automatic rather than emotional?" If yes, that points toward the autonomic nervous system as the site of disruption.
What this cluster looks like in practice
- Heart palpitations — fluttering, pounding, or irregular beats at rest
- Sudden racing pulse with minimal or no physical trigger
- Lightheadedness or near-fainting when standing (orthostatic hypotension / POTS-type)
- Profound fatigue — not relieved by sleep or rest
- Temperature dysregulation — persistently cold, or unexpected sweating
- Shortness of breath without lung or structural heart disease
- Blood pressure variability — episodes of low or fluctuating BP
- Exercise intolerance — significant symptom worsening after light activity
- Post-exertional malaise — "crashes" that last hours or days
- Unexplained muscle weakness disproportionate to effort
Autonomic dysfunction and cardiac involvement are recognised features of tick-borne illness. Lyme carditis (affecting conduction), dysautonomia, and POTS-like presentations have all been documented in association with Borrelia and co-infections such as Bartonella. When these symptoms appear alongside cognitive or musculoskeletal involvement, and standard cardiac investigations are unremarkable, tick-borne illness is worth raising explicitly with a knowledgeable clinician. Educational context only, not a diagnosis.
Where to go next
Standard cardiac tests are not designed to find autonomic dysregulation. Understanding what different tests measure — and which ones are relevant here — changes the conversation with any clinician.
Healing mentality checkpoint
Cardiac and autonomic symptoms generate a particular kind of anxiety — because the heart is involved and everything feels urgent. Understanding that normal tests do not mean nothing is wrong, and that there are different investigative paths, is the first calming piece of information.
Read about healing mentality →Sources & further reading
- Wormser G.P. et al. — Lyme carditis (Heart Rhythm, 2015)
- Younger D.S. — Lyme neuroborreliosis and the peripheral nervous system (J Peripher Nerv Syst, 2019)
- ILADS clinical guidelines — ilads.org
- Columbia University Lyme and Tick-borne Disease Research Center
Last updated: March 2026