Pacemakers and methylprednisolone pulse therapy in immune-related myocarditis concomitant with complete heart block

Immune-related cardiotoxicities are uncommon but potentially fatal. The study aims to evaluate the value of pacemakers and methylprednisolone pulse therapy (MPPT) to patients with immune-related myocarditis concomitant with complete heart block (CHB). We first reviewed medical records of three patients with immune-related myocarditis concomitant with CHB. For the pooled analysis, we searched related cases with immune-related myocarditis in the PubMed database and screened the patients. Clinical characteristics, management, and outcomes were summarized. Our three patients developed immune-related myocarditis concomitant with CHB about 2 weeks after receiving pembrolizumab, and were successfully treated with pacemaker implantation and high-dose steroids (two received MPPT). In the pooled analysis, 21 cases were eligible with an overall fatality rate of 52%. Patients with pacemakers had a fatality rate of 38%, significantly lower than patients without them (38% vs 100%; p = 0.035), particularly the MPPT subgroup (25% vs 100%; p = 0.019). All five patients without pacemakers expired. Among patients with pacemakers, MPPT patients tended to have an inferior rate compared with non-MPPT patients. Timely pacemaker implantation played a crucial role in improving the outcomes of patients with immune-related myocarditis concomitant with CHB. Patients receiving MPPT appeared to have a better prognosis. Additionally, multidisciplinary consultation should be recommended for better management.