The Significance of a Wide Tse Loop.

IN recent years there has been increasing interest in the clinical application of spatial vectorcardiography. Some comparative studies have indicated that the vectorcardiogram may be significantly superior to the conventional scalar electrocardiogram in the diagnosis of myocardial infarction and ventricular hypertrophy." 2 The Frank lead system3 has many theoretical advantages over the older vectorcardiographic recording systems and has also been claimed to be superior to the older systems for clinical application.2 The growing number of vectorcardiographic situdies with use of the Frank reference frame tends to indicate its acceptance as an improved, although by no means ideal, system. Investigations in clinical vectorcardiography have primarily been directed to the study of the QRS loop. Very little information can be obtained from the current literature concerning the T loop, especially with regard to its configuration.4-8 The purpose of the present investigation is to study with the Frank system: the normal configuration of the Tst loop,* particularly with regard to its length and width ratio; the pathologic entities associated with abnormally wide TsE loops; and the comparative value of vectorcardiography in the study of the process of repolarization, especially as to whether it will supply