IMPORTANCE OF PREIMPLANTATION PROCEDURES IN CANDIDATES FOR AN IMPLANTABLE ATRIAL DEFIBRILLATOR

Importance of Preimplantation Testing. Introduction: Due to the limite d efficacy of antiarrhythmic drugs for the treatment of atrial fibrill ation, several nonpharmacologic therapeutic options have been develope d. One of these options is an implantable atrial defibrillator for pat ients with severe symptoms and infrequent drug-refractory episodes of atrial fibrillation. The purposes of this study were: (1) to evaluate how many patients with atrial fibrillation are possible candidates for an implantable atrial defibrillator; and (2) to report the results an d findings of preimplantation testing in a single center. Methods and Results: From our atrial fibrillation outpatient clinic, we evaluated the number of possible candidates for an atrial defibrillator using th e following criteria: (1) recurrent persistent atrial fibrillation; (2 ) long-lasting but infrequent episodes; (3) refractory to antiarrhythm ic drugs; (4) capability of maintaining normal sinus rhythm; and (5) n o factors increasing proarrhythmic risk. In those patients eligible fo r an atrial defibrillator, a separate preimplantation test was perform ed to evaluate atrial defibrillation limits and patient acceptance. Th irty-one of 196 patients were possible candidates for an atrial defibr illator. Fourteen of these 31 patients agreed to participate in the ME TRIX(TM) clinical study phase I on atrial defibrillators. Six of these patients met implantation criteria; two patients refused permanent im plantation because of intolerable pain. Implantation was performed in four patients; however, one patient could not be cardioverted intraope ratively despite a successful preimplantation test. Conclusion: About 16% of selected patients with atrial fibrillation are possible candida tes for an atrial defibrillator. However, successful preimplantation t esting does not exclude implantation failure.