These studies concern practical clinical aspects related to the problem of Sudden Cardiac Death (SCD). The objectives continue in the main direction delineated in the Grant proposal with modifications and newer emphasis derived from findings during this past year. The major goals involve the following: 1. Development of rapid screening methods for advanced grades of ventricular premature beats (VPBs) and defining differences between so-called benign and malignant ectopics. The methods are to include trendscription, ministress testing as compared to standard exercise stress testing and ambulatory monitoring. 2. Testing the feasibility of precordial mechanical stimulation for exposure of myocardial electrical instability of inpatients within maliganant ventricular arrhythmias and compare this to the elicitation of the repetitive ventricular response (RVR) by invasive techniques. 3. To continue the rationalization in the use of antiarrhythmic drugs and define their hazard both in provoking arrhythmias as well as in exposing potential adverse hemodynamic effects.