DUAL-CHAMBER AUTOMATIC IMPLANTABLE DEFIBRILLATOR - RESULTS IN 16 CASES

In view of the large number of inappropriate shocks observed in patien ts with implanted defibrillators, improved detection of ventricular ar rhythmias has become a major objective. The addition of an atrial cath eter has been proposed to improve discrimination between ventricular a nd non-ventricular arrhythmias. Besides this function, the additional catheter could be used for DDD pacing without risk of interaction betw een the pacemaker and defibrillator. The authors report their initial experience in 1.6 patients implanted with a DDD pacemaker. The indicat ion was resuscitated sudden death (N=5) or ventricular tachycardia (N= 11). The choice of a DDD defibrillator was justified by a bradycardia (N=9), haemodynamic factors (N=4) or supraventricular tachycardia (N=3 ). The devices used were the Defender 9001 (ELA Medical SA, France, N= 3), the Ventak AV 1810 and the Ventak AV II DR 1821 (Guidant/CPI, Inc. USA, N=11 and N=2 respectively). There were three immediate complicat ions. After 2 to 29 months' follow-up, 5 patients had received appropr iate treatment by their devices. Five patients had inappropriate shock s : one patient received a shock triggered by electrical interference, two others had no active sensing algorithme when the shocks were deli vered, and the other two had an activated algorithme with 1/1 conducti on of a supraventricular arrhythmia. No recurrences were recorded afte r reprogramming the device. DDD or VDD pacing was permanent in 9 patie nts and intermittent in 3 others. Seven patients had dilated cardiomyo pathy and severe cardiac failure and were clinically improved by dual chamber pacing. In many patients, candidates for a defibrillator, this new generation of devices has improved specificity of arrhythmia dete ction and cardiac pacing without risk of interaction. The authors prop ose a classification of the indications for a DDD defibrillator.