CLINICAL INVESTIGATION OF ANTIARRHYTHMIC DEVICES - A STATEMENT FOR HEALTH-CARE PROFESSIONALS FROM A JOINT TASK-FORCE OF THE NORTH-AMERICAN-SOCIETY-OF-PACING-AND-ELECTROPHYSIOLOGY, THE AMERICAN-COLLEGE-OF-CARDIOLOGY, THE AMERICAN-HEART-ASSOCIATION, AND THE WORKING GROUPS ON ARRHYTHMIAS AND CARDIAC PACING OF THE EUROPEAN-SOCIETY-OF-CARDIOLOGY BASED ON THE PROCEEDINGS OF A POLICY CONFERENCE HELD NOVEMBER 15-16, 1993, WASHINGTON, DC