Evaluation of pharmacological and device therapy for the management of life-threatening arrhythmias

During the past two decades, a large number of controlled clinical trials o f various forms of antiarrhythmic therapy have been designed and carried ou t. The application of the results of these trials is dependent upon the stu dy designs and the degree to which outcomes can be generalized and applied to clinical practice. For the interpretation of clinical trials, five facto rs are essential: (1) insight into the specific endpoints measured and the limitation of outcomes data; (2) weighing up the difference between placebo -controlled trials and trials which incorporate a positive control (compara tive) therapy; (3) appreciating the meaning of intention-to-treat analysis and recognition that on-therapy analysis may help interpretation; (4) under standing the difference between relative reduction of event rates (efficacy ) and absolute benefits (efficiency); (5) evaluating the impact of various trials on the population at risk for a given outcome event. This paper disc usses the importance and limitations of each of these elements of trials st rategy, with the aim of providing the reader with an insight into the integ ration of new data into the practise of cardiology generally and for the ma nagement of arrhythmias specifically.