Vectorcardiographic Studies in Acquired Valvular Disease with Reference to the Diagnosis of Right Ventricular Hypertrophy

gram is not always reliable in demon-strating right ventricular hypertrophy (RVH), this is particularly true in patients with ac-quired valvular disease, or with mild or mod-erate RVH.'12 Such discrepancies are under-standable when one considers that the most commonly used criteria for RVH are based on voltages,3-5 and that only in cases of severe or massive RVH can the electromotive forces generated in the right ventricle (RV) counter-balance those produced in the left ventricle (LV).1 2 Our experience as well as that of several others-9 has demonstrated the usefulness and merits of the orthogonal vectorcardiogram. Furthermore, Toshima et al.'0 using the Schmitt-Simonson system (SVEC III) in pa-tients with mitral and aortic valvular disease and left ventricular hypertrophy (LVH) not only were able to evaluate the hypertrophy more accurately but also in most cases were able to make a correct diagnosis of the specific valvular lesion causing it. Mitral stenosis is known to produce pul-monary venous obstruction, left atrial enlarge-ment, pulmonary hypertension, and ultimately RVH. The purpose of this paper is to report the vectorcardiographic findings, with use o