Background:Although there is an apparent rapid and spontaneous recovery of left ventricular ejection fraction (LVEF) in patients with Takotsubo syndrome (TTS), recent studies have demonstrated a long-lasting functional impairment in those patients. The present study sought to evaluate the predictors of incomplete recovery following TTS and its impact on cardiovascular mortality.Methods and Results:Patients with TTS between 2008 and 2018 were retrospectively enrolled at 3 different institutions. After exclusion of in-hospital deaths, 407 patients were split into 2 subgroups according to whether their LVEF was >50% (recovery group; n=341), or ≤50% (incomplete recovery group; n=66) at the chronic phase. Multivariate logistic regression analysis found that LVEF (odds ratio OR: 0.94; 95% confidence interval CI: 0.91–0.98; P<0.001) and C-reactive protein levels (OR: 1.11; 95% CI: 1.02–1.22; P=0.02) at discharge were independent predictors of incomplete recovery. At a median follow up of 52 days, a higher cardiovascular mortality was evident in the incomplete recovery group (16% vs. 0.6%; P<0.001).Conclusions:This study demonstrated that incomplete recovery after TTS is characterized by residual systemic inflammation and an increased cardiac mortality at follow up. Altogether, the present study findings determined that patients with persistent inflammation are a high-risk subgroup, and should be targeted in future clinical trials with specific therapies to attenuate inflammation.