PURPOSE: Early identifi cation of specifi c patient subgroups at high risk of developing life-threatening infective endocarditis (IE) complications is of paramount importance. Better stratifi cation may allow more intensive treatment of these patients and positively infl uences clinical outcomes. METHODS: We carried out a retrospective survey of consecutive left-sided IE adult patients, admitted over a 15-year period to two main tertiary care centres in the Czech Republic. RESULTS: Among a group of 196 patients (155 males; median age 64 years), a total of 206 left-sided IE episodes were identifi ed. Perivalvular extension of infection was most frequently seen in prosthetic aortic valve endocarditis (OR 6.706, p < 0.0001). Valve prolapse/perforation during IE episodes was signifi cantly associated with mitral valve IE (OR 2.136, p = 0.026) and vegetation length (OR 1.055, p = 0.009). Septic shock was signifi cantly related to two main risk factors: S. aureus infection (OR 8.459, p = < 0.0001) and smoking (OR 8.403, p=0.001). Mitral valve IE with a vegetation length ≥13 mm was the strongest risk factor for this complication (OR 3.24, p=0.001), followed by S. aureus infection (OR 3.59, p = 0.002). Finally, septic shock (OR 6.000, p = 0.001) represented the most important risk factor of in-hospital mortality. CONCLUSIONS: This study provides the most detailed profi le of complication predictors related to left-sided IE in Central Europe. Early individual stratifi cation of IE related occurrence of complications might help to decrease extremely high morbidity and mortality of this disease (Tab. 5, Ref. 37).