Myocarditis complicated by ventricular tachycardia: prevalence, outcomes and acute ablation results

Abstract Background Myocarditis in most cases is a self-limiting condition that resolves spontaneously without intervention. However, myocarditis can be accompanied by ventricular tachycardia (VT) and can be life-threatening. The rate of complications and mortality is higher when VT occurs. Catheter ablation can occasionally be required for the treatment of VT, however, there is limited information regarding the safety of the procedure in myocarditis patients. Aim We aimed to assess the prevalence of patients diagnosed with VT due to acute myocarditis, to analyze the population that underwent ablation during hospitalization and their acute outcomes. Methods This retrospective study utilized the National Inpatient Sample (NIS) database to analyze in-hospital outcomes of myocarditis in US patients, with and without VT, between 2016 and 2019. Further analysis compared patients with myocarditis associated VT according to performance of ablation treatment. Patient demographics, comorbidities, procedures, and in-hospital outcomes were extracted using ICD-10-CM codes. Results Among 17,845 estimated hospitalizations for myocarditis, 7.7% (n=1385)had VT during their hospitalization. These patients were more likely to have renal and infectious diseases, anemia and atrial arrhythmias, and although having higher rates of structural cardiac problems, other classical risk factors were less prevalent. Outcomes of patients with VT were consistently worse, including a 4.5X in-hospital mortality (7.9% vs. 1.8;p0.001). VT ablation was performed in 13.7%(n=190) of cases with VT, more often with an infectious etiology, and the in-hospital complications and mortality were significantly higher (42.1% vs 20.9%;p0.001, and 15.8% vs 6.7%;p0.001, respectively). Conclusions Myocarditis patients complicated by VT have significantly worse in-hospital outcomes. While the decision to undergo ablation is beyond the scope of this analysis, the 1 out of 7 patients undergoing ablation had less favorable outcomes. Further research is needed to assess the criteria for ablation and probability of favorable outcomes in this complex patient population.Analysis flow chart