Abstract 14249: COVID-19 and Complete Heart Block in a Vaccinated Adult

Introduction: Complete heart block (CHB) in association with Covid-19 is uncommon and has been described primarily in the pre-vaccine time period. In the setting of acute Covid-19 infection, decision to treat CHB with permanent pacemaker (PPM) is often uncertain as the CHB may resolve or persist. We present a case of reversible CHB and Covid-19 infection in a vaccinated healthy 28-year-old. Case: A healthy 28-year-old female presented after syncope. She had been vaccinated three times against Covid-19 with Pfizer-BioNTech mRNA vaccine with her third dose four months prior. She had known Covid-19 exposure and developed sore throat three days prior to presenting with syncope. She had no other symptoms. Physical exam was remarkable only for bradycardia. Labs showed positive Covid-19 PCR test and elevated troponin of 0.396 ng/mL. Complete blood counts, metabolic panel, ESR and CRP were normal. Lyme IgM and IgG were negative by Western blot. ECG showed CHB with a rate of 35 beats per minute (Figure 1A). Echocardiogram showed no abnormalities. The patient remained in CHB for 24 hours, at which point PPM was implanted after shared-decision making. Post-PPM ECG showed AV-paced rhythm (Figure 1B). At follow up, PPM interrogation showed that she transitioned to sinus rhythm with right bundle branch block (RBBB) followed by a return to normal sinus rhythm without RBBB 5 days after implantation (Figure 1C). Cardiac MRI two months after PPM implantation showed no abnormalities. Discussion: This was a case of Covid-19 associated myocardial injury with CHB in a fully-vaccinated, healthy adult treated with PPM. Despite vaccination, this patient experienced myocardial and conduction system involvement during acute Covid-19 infection. Myocardial injury along with this ECG progression suggested that there was transient inflammation of the myocardial septum resulting in CHB. It may be reasonable to delay PPM implantation in cases of CHB and Covid-19 infection as the CHB may be transient.