Active infective endocarditis (AIE) involving native and especially prosthetic aortic valve is often complicated by conduction abnormalities. These conduction disturbances are considered to represent extension of infection from the valve to the annulus and surrounding myocardium. The authors report their experience of conduction disorders in 6/8 patients in whom the aortic prosthetic valve infection was complicated by periprosthetic abscess. They underline the importance of conduction abnormalities as early markers of severe complication in patients with AIE. In fact, their detection is a useful tool in revealing severe complications since clinical, laboratory and other noninvasive examinations do not always allow early diagnosis of the extension of infection to the surrounding myocardium.