This application is a proposal to establish a statistical and data coordinating center for the multicenter study of electrophysiologic (EP)-guided antiarrhythmic therapy in patients with non-sustained ventricular tachycardia (VI). The study will enroll approximately 3,000 patients with chronic coronary artery disease, diminished left ventricular function, and asymptomatic non-sustained VT. After undergoing a baseline EP study, patients with inducible sustained at will be randomized to receive either no specific therapy, or antiarrhythmic therapy guided by serial electrophysiologic studies. AlI patients will be followed via clinic visits at 3 month intervals. The primary endpoint is sudden death or resuscitated cardiac arrest. Nine hundred patients will be randomized, with one-half allocated to each treatment arm. Patients eligible for randomization who choose not to enter the trial will he characterized and followed in a prospective registry. Patients who do not exhibit inducible sustained VT at the baseline EP study will also be enrolled in the registry and followed at similar intervals. As an integral part of this study, the coordinating center will perform the following major functions: (1) participate in all phases of planning and study design, (2) coordinate the preparation of data collection forms and procedures, (3) prepare and distribute a manual of operations, (4) provide training and guidance in data flection procedures, (5) coordinate the randomization of patients, (6) efficiently organize the flow and management of all patient data (baseline and follow-up), (7) establish and strictly adhere to high standards of quality control for data management, (8) perform on-site monitoring of completed data forms, (9) prepare regular status reports and summary information for study committees, (10) coordinate and perform appropriate statistical analyses of study data, and (11) participate in the preparation of study publications. Noteworthy features of this proposal include: a detailed assessment of sample size requirements; centralized (telephone) randomization of patients; assignment of antiarrhythmic drugs in a random order (in the EP-guided therapy arm); centralized double data entry; complete follow-up of all patients (including those not randomized); on-site review of study forms by trained nurse monitors; use of economical and efficient computer hardware and software; state-of-the-art methods of data analysis; and an experienced team of investigators. Through the services it provides, which extend across all aspects of study design, data collection, data management, and data analysis, this coordinating center will be a vital resource in the execution of this study. The results of the study are anticipated to provide important new clinical information and to greatly enhance the management and treatment of patients with non-sustained ventricular tachycardia.