A Practical Approach to Atrioventricular Dissociation Secondary to Lyme CarditisCarmela Aromin1, Anupa Chanda1, Garry R. Thomas1,2

1 Unity Health Toronto (St. Joseph’s Health Centre), Department of Medicine, Division of Cardiology, Toronto, Ontario, Canada.2 University of Toronto, Faculty of Medicine, Toronto, Ontario, Canada

• Lyme carditis can result in transient but hemodynamically significant complete heart block (CHB)

• Early recognition and treatment with antibiotics and pacing support often has a favourable prognosis

• Challenge: Duration of required pacing support is variable

Objective: We present the use of a temporary-permanent pacemaker (TPPM) as a feasible and practical approach to the management of Lyme-induced CHB

Clinical Investigations

Presenting ECG CHB with a junctional escape

Labs Normal troponin↑ WBC (15.3X10^9/L), ↑ CRP (108 mg/L)

CT Chest No evidence of hilar adenopathy

Echocardiogram LVEF: Low-normal

Lyme Serology Positive (Results available 10 d after admission)

• Ceftriaxone 2 g IV daily was empirically started due to a high suspicion of Lyme disease

• Ventricular pacing (VP) burden remained high 5 days after insertion of temporary transvenous pacemaker (TTVP) set at 40 min-1

• Time to AV conduction recovery remained unclear so a TPPM was implanted on day 6 of admission using the same venous access as the TTVP (Figure 3)

• Patient discharged home POD 1 with 21-day course antibiotics

• Patient returned to hospital POD 3 for interrogation. Stable function with 14%-VP. Wenckebach conduction on ECG

• POD 18, antibiotics completed and 48-hr Holter showed resolved heart block. Endocardial lead was removed inthe pacemaker clinic without complications

Figure 4. POD 3 ECG showing Wenckebach conduction

Figure 5. POD 18 ECG showing resolved heart block

• A temporary-permanent pacemaker is a practical solution for CHB secondary to Lyme Carditis of unknown recovery time

• This allows for early patient ambulation and safe dischargewhile they are concurrently treated with antibiotics

Background

Table 1. Clinical investigations during hospital admission

Case (Continued) Outcomes

Conclusion

• 31M previously well presenting with syncope

Figure 1. CHB with ventricular asystole for 31 seconds at admission

• Four weeks prior, camping in Ontario and had a tick bite with subsequent rash

Figure 2. Erythema migrans suspicious for Lyme disease Figure 3. TTPM (VVI 40 min-1) implanted via right IJ vein

A B

Case