[The implantable automatic defibrillator].

Technical advances in the design of implantable automatic defibrillators have been constant since the introduction of these devices in the mid 80s. The most obvious advance is the miniaturisation of the devices from which all components have benefited. The capacity of the batteries has improved inversely proportionally to their size, even if the longevity has not always lived up to expectations. The volumic energy of the condensers has improved and their technology also, and their size has decreased. Condensers are still usually made by the electrolytic/aluminium method but tantalum technology is bound to become more generalised because it presents so many advantages. Above all, the circuitry has benefited from the progress of micro-electronics, associating miniaturisation with an increase in more and more complex functions...but requiring more electrical current. Of these functions, algorithms to detect arrhythmias has reduced the number of inappropriate shocks but do not yet have excellent specificity either in single or in dual chamber sensing. Defibrillators incorporating a multisite anti-bradycardiac function are more and more popular because of the close relationship between cardiac failure and sudden death.