This handout is for cardiogenic shock / high-grade av block — lyme carditis. Your care team identified this based on: new high-grade av block (mobitz ii / chb) in patient from endemic region with tick exposure or erythema migrans → lyme carditis until proven otherwise.
Other reasons your team may use this plan: fluctuating-degree av block (1st-degree → mobitz i → chb hour-to-hour) in previously healthy young/middle-aged adult — pathognomonic for lyme carditis; recent erythema migrans rash + new palpitations / syncope / dyspnea → lyme carditis evaluation with ecg + echo + serology; fulminant lyme myocarditis presentation with new severe lv dysfunction + shock physiology in patient from endemic area.
Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.
| Medication | Starting dose | How | When | What it does |
|---|---|---|---|---|
| ceftriaxone | 2 g IV q24h × 14-21 days (28 days if concurrent neuro Lyme) | IV | q24h | IDSA 2021 Lyme guideline (Lantos PMID 33417672) strong recommendation for parenteral therapy in high-grade AV block / hospitalized carditis; standard 14-21 days, extend to 28 days if concurrent neuroborreliosis |
| doxycycline | 100 mg PO BID × 14-21 days; 200 mg IV q12h alternative if PO not tolerated | PO/IV | BID | IDSA 2021 outpatient option for mild Lyme carditis (1st-degree AV block, asymptomatic, PR <300 ms); IV doxycycline alternative if severe penicillin allergy precludes ceftriaxone (Wormser PMID 12767092 erythema migrans equivalence anchor) |
| norepinephrine | 0.05–0.5 µg/kg/min titrate MAP ≥65 | IV | continuous | SOAP-II PMID 20200382 — NE first-line vasopressor in CS; rare in Lyme carditis but used in fulminant myocarditis variant |
| dobutamine | 2.5–10 µg/kg/min titrate | IV | continuous | Inotropic support in fulminant Lyme myocarditis variant with LV dysfunction; CAUTION — may exacerbate ventricular arrhythmias in active myocarditis |
| furosemide | 40–80 mg IV bolus then titrate | IV | bolus or continuous | Decongest if pulm congestion from myocarditis-related LV dysfunction (ESC 2021 acute HF) |
| atropine | 0.5 mg IV q3-5 min up to 3 mg total | IV | PRN | 2018 ACC/AHA Bradycardia Guideline (Kusumoto PMID 30412705) — atropine first-line pharmacologic for symptomatic bradycardia; bridge until temporary pacing available; LIMITED efficacy in infranodal block (CHB) but worth attempting |
Plan: Lyme carditis with AV block / cardiogenic shock — antibiotics cure underlying infection; temporary pacing bridges conduction recovery; CS support if fulminant myocarditis component
Contact your care team if any of the following happen:
Call 911 or go to the nearest emergency room right away if you have:
Repeat ECG + echo at 1 month + 3 months post-completion; cardiology / EP follow-up if persistent conduction abnormality at 6 weeks (pacer evaluation); ID follow-up for concurrent Lyme features (arthritis, neuro); tick-bite prevention counseling; consider single-dose doxycycline 200 mg post-exposure prophylaxis future Ixodes attachments ≥36 h per IDSA 2021
Guideline: IDSA / AAN / ACR Lyme Disease Clinical Practice Guidelines 2021 (Lantos PMID 33417672); CDC Lyme Disease Clinician Guidance + Modified Two-Tier Testing 2019; 2018 ACC/AHA/HRS Bradycardia Guideline (Kusumoto PMID 30412705); AHA Scientific Statement on Acute Myocarditis 2020 (Cooper); SCAI 2022 CS staging (Naidu PMID 35718438)