Bacterial endocarditis is most commonly seen in:

Valvular disease alters blood flow and produces jet effects that disrupt the endothelial surface, providing a nidus for attachment and infection of microorganisms that enter the bloodstream. Predisposing valvular abnormalities- Rheumatic involvement of any valve Bicuspid aoic valves, calcific or sclerotic aoic valves Hyperophic subaoic stenosis, mitral valve prolapse Congenital disorders- VSD, ASD, TOF, PDA, coarctation of the aoa Regurgitation lesions are more susceptible than stenotic ones. Though PDA is a close answer, since VSD is more common a lesion and pressure gradient between LV and RV is more than pressure gradient between aoa and pulmonary aery, VSD should be answered for the above question