Complete heart block from Lyme disease can deteriorate rapidly even after antibiotics begin. A 26-year-old man progressed from 2:1 AV block to complete block with asystole within 24 hours of starting treatment, requiring emergency pacemaker placement. His complete recovery and pacemaker removal after 19 days demonstrates the reversible nature of Lyme carditis when managed appropriately.

Initial Emergency Presentation

The patient was evaluated in the emergency room with presyncope (lightheadedness, muscle weakness) and worsening fatigue. Telemetry monitoring demonstrated a “2:1 AV block alternating with complete heart block and a junctional escape rhythm in the range of 30 beats per minute,” according to Chaudhry and colleagues from the Department of Cardiology and Electrophysiology, Aultman Hospital, Ohio.

This cardiac presentation was immediately life-threatening. 2:1 AV block means only half of the electrical signals from the atria were reaching the ventricles. Complete heart block means no signals were getting through at all. The junctional escape rhythm at 30 beats per minute was the only thing preventing cardiac arrest — a backup pacemaker deep in the heart generating just enough electrical activity to maintain minimal cardiac output.

The alternation between these rhythms showed unstable electrical activity that could deteriorate further at any moment.

Empiric Treatment Initiated

Doctors suspected Lyme disease and started intravenous ceftriaxone. This was the correct approach — empiric antibiotics for suspected Lyme carditis rather than waiting for serologic confirmation.

But the patient’s course demonstrates that even appropriate treatment doesn’t guarantee immediate stabilization.

Deterioration Despite Antibiotics

Within 24 hours the man’s condition had worsened. “Twenty-four hours after admission, he had loss of junctional escape with underlying complete heart block and asystole with near syncope,” describes Chaudhry.

This progression is critical to understand. The patient was on appropriate antibiotics. IV ceftriaxone was killing the spirochetes. Yet he got worse, not better.

Loss of junctional escape means the backup pacemaker failed. With complete heart block and no escape rhythm, the heart stopped generating electrical activity entirely — asystole. The patient nearly passed out from inadequate blood flow to the brain.

This near-cardiac arrest occurred while on antibiotics for Lyme disease. The treatment was correct, but the cardiac damage had already progressed to the point where spirochetal die-off and inflammation couldn’t resolve quickly enough to prevent life-threatening arrhythmias.

Emergency Pacemaker Placement

The man required a pacemaker. “Emergent right subclavian access was obtained for temporary pacing and placement of an active fixation permanent pacemaker lead,” explains Chaudhry.

This describes placement of what’s called a temporary permanent pacemaker — using permanent pacemaker hardware but as an external device. The lead (wire) was actively fixed to the heart muscle, but the generator remained outside the body, allowing it to be removed once heart function recovered.

This approach gave the patient the stability of a permanent pacemaker without committing a 26-year-old to permanent hardware if his conduction recovered with antibiotic treatment.

Diagnostic Confirmation

Serologic tests were positive by ELISA and confirmed with the Western Blot IgM.

The positive IgM with negative IgG (not mentioned, but implied by the emphasis on IgM) suggests early disseminated infection. Lyme carditis typically develops weeks to months after infection, often before the full IgG antibody response develops.

Understanding the Pathology

“Lyme carditis is a dreaded complication of disseminated Lyme disease and is caused by direct cardiac invasion by spirochetes,” Chaudhry states.

The authors summarize the underlying pathology: “There is initially a transmural inflammation with macrophages and neutrophils followed by a band-like appearance of lymphocytes. Interstitial fibrosis, as well as small and large vessel vasculitis, pericarditis, myocarditis, acute coronary syndromes, and coronary artery aneurysms can potentially occur.”

This description reveals the complexity of cardiac Lyme involvement:

• Transmural inflammation: Inflammation extends through the full thickness of the heart wall, not just superficial involvement
• Multiple immune cells: First macrophages and neutrophils (acute inflammation), then lymphocytes (chronic inflammation)
• Interstitial fibrosis: Scar tissue formation that could become permanent if treatment is delayed
• Vasculitis: Blood vessel inflammation affecting both small and large cardiac vessels
• Pericarditis: Inflammation of the heart’s outer lining
• Myocarditis: Inflammation of the heart muscle itself
• Acute coronary syndromes: Can mimic heart attack
• Coronary artery aneurysms: Weakening and bulging of coronary arteries

The breadth of potential cardiac involvement explains why Lyme disease can cause so many different cardiac manifestations.

Recovery and Pacemaker Removal

The placement of an external pacemaker enabled the patient to be discharged home after 12 days while he continued to recover on IV antibiotics. His pacemaker was removed at day 19.

This timeline is remarkable:

• Day 1: Admission with 2:1 block alternating with complete block
• Day 2: Deterioration to asystole, emergency pacemaker placement
• Day 12: Stable enough for home discharge with external pacemaker
• Day 19: Pacemaker removed — heart block completely resolved

From near-cardiac arrest to complete recovery in 19 days. This demonstrates how effectively antibiotics resolve Lyme carditis when given adequate time to work.

The ability to discharge home with an external pacemaker was critical for this young patient. Rather than 19 days hospitalized, he spent only 12 days in-hospital, then recovered at home while the antibiotics completed their work.

Why Worsening Occurred Despite Treatment

The initial deterioration despite antibiotics deserves explanation. Several factors could contribute:

Jarisch-Herxheimer reaction: When antibiotics kill spirochetes rapidly, the bacterial death releases inflammatory substances that can temporarily worsen symptoms. This reaction is well-documented in Lyme disease treatment.

Progression of existing inflammation: The cardiac inflammation was already severe at presentation. Antibiotics stop new spirochetal invasion but don’t immediately reverse existing damage. The inflammatory cascade already in motion continued for hours to days.

Critical tipping point: The patient presented at a moment when his heart block was barely compensated. Any additional stress — including inflammatory response to dying spirochetes — pushed him over the edge into complete decompensation.

The lesson: starting antibiotics promptly is critical, but cardiac monitoring must continue because patients can worsen before they improve, particularly in the first 24-48 hours of treatment.

Clinical Perspective

This case challenges the assumption that appropriate antibiotics immediately stabilize Lyme carditis patients. The 26-year-old man was diagnosed quickly, antibiotics started empirically, yet he still progressed to asystole within 24 hours.

This doesn’t mean the treatment was wrong — it means the disease was severe and the cardiac damage had reached a critical point. The antibiotics were working, but the heart couldn’t maintain adequate rhythm while inflammation resolved.

The emergency pacemaker likely saved his life. Without artificial pacing when his junctional escape failed, he would have had cardiac arrest. The decision to place a temporary permanent pacemaker rather than a fully implanted permanent device was wise — it provided necessary cardiac support while allowing for removal once conduction recovered.

For young patients with Lyme carditis, avoiding permanent pacemaker placement should always be the goal. A 26-year-old with a permanent pacemaker faces 50+ years of device complications, generator replacements, and psychological burden. The temporary approach used here gave the patient’s heart time to recover without committing him to permanent hardware.

The complete resolution by day 19 validates the decision. Had a permanent pacemaker been placed immediately, it would have been unnecessary — the patient’s heart recovered completely and maintained normal conduction without artificial pacing.

This case also demonstrates why close cardiac monitoring is essential in the first days of treatment. The patient was already hospitalized when he deteriorated to asystole. If he had been managed as an outpatient with oral antibiotics, that moment of cardiac arrest could have occurred at home with potentially fatal consequences.

Frequently Asked Questions

Can complete heart block from Lyme disease be reversed?

Yes. This patient had complete resolution by day 19 of antibiotic treatment. Most Lyme carditis patients recover completely when treated appropriately, avoiding the need for permanent pacemakers.

Why do some Lyme carditis patients get worse after starting antibiotics?

Initial worsening can occur from Jarisch-Herxheimer reaction (inflammatory response to dying spirochetes) or progression of existing inflammation before antibiotics take effect. Close cardiac monitoring is essential in the first 24-48 hours of treatment.

Do all Lyme carditis patients with complete heart block need pacemakers?

Most need temporary pacing during treatment, but permanent pacemakers are rarely necessary. This patient required temporary pacing for 19 days, then his heart block resolved completely. Temporary approaches avoid permanent devices in young patients.

How long does it take for complete heart block from Lyme disease to resolve?

Typically days to weeks. This patient’s heart block resolved in 19 days. Recovery timeline varies but most patients see improvement within 1-2 weeks of starting antibiotics, with complete resolution by 3-4 weeks.

Can Lyme carditis cause cardiac arrest?

Yes. This patient experienced asystole (cardiac standstill) 24 hours after admission, requiring emergency pacing. Lyme carditis can be fatal when complete heart block progresses to asystole or ventricular arrhythmias without appropriate intervention.

Should Lyme carditis patients be hospitalized?

Patients with high-degree heart block should be hospitalized with cardiac monitoring. This case shows why — the patient deteriorated to asystole within 24 hours despite being on appropriate antibiotics. Outpatient management would have been dangerous.

What is a temporary permanent pacemaker?

It uses permanent pacemaker hardware (actively fixed lead) but keeps the generator external to the body. This provides stable pacing during recovery while allowing easy removal once heart block resolves, avoiding permanent implantation in young patients.