CHD increases the risk of infective endocarditis due to the substrate of prosthetic materials and residual lesions. However, lesion-specific and mortality risks data are lacking. We sought to analyse clinical course and mortality of infective endocarditis in a cohort of adult CHD.

Retrospective analysis of all cases of proven and probable infective endocarditis (Duke’s criteria) followed in our adult CHD clinic between 1970 and August, 2021. Epidemiological, clinical and imaging data were analysed. Predictors of surgical treatment and mortality were assessed using regression analysis.

During a mean follow-up of 15.8 ± 10.9 years, 96 patients had 105 infective endocarditis episodes, half with previous cardiac surgery (corrective or palliative). The most frequent diagnoses were: ventricular septal defect, bicuspid aortic valve, Tetralogy of Fallot and pulmonary atresia. The site of infection was identified by echocardiography in 82 episodes (91%), most frequently in aortic (n = 27), tricuspid (n = 15), and mitral (n = 13) valves. Blood cultures were positive in 79% of cases, being streptococci (n = 29) and staphylococci (n = 23) the predominant pathogens. Surgery was necessary in 40% and the in-hospital mortality was 10.5%, associated with heart failure (p < 0.001; OR 13.5) and a non-surgical approach (p = 0.003; OR 5.06).

In an adult CHD cohort, infective endocarditis was more frequent in patients with ventricular septal defect and bicuspid aortic valves, which contradicts the current guidelines that excludes them from prophylaxis. Surgical treatment is often required and mortality remains substantial. Prevention of this serious complication should be one of the major tasks in the care of adults with CHD.