This Study demonstrates the feasibility of developing an analog computer model of the electrical events of the heart, based on a rational application of experimental knowledge of ventricular depolarization.Not only did the results resemble normal vectorcardiographic loops, but also changes were analogized from concepts of pathologic physiology that produced configurations resembling known clinical vectorcardiographic abnormalities.It is expected that all known vectorcardiographic deviations can eventually be simulated on a rational basis, and, further, that previously unrecognized alterations may be found permitting diagnosis of infarction or other processes not possible by present knowledge and criteria.The present study strongly supports the view that most, if not all, of the factors known to influence the electrical field of the heart can be simulated by computer technics. When this is accomplished, it may be possible to remove much of the dogma and empiricism from traditional electrocardiographic theory and place it on a more rational foundation. The need for further exploration in this area seems imperative.