Clinical Studies on the Ventricular Strain Pattern Electrocardioogram (I) : Clinical Statistical Studies

Abstract

In order to study clinically the genetic mechanism of the ventricular strain pattern ECG the author studied the relationship between the ventricular strain pattern ECG and various clinical laboratory tests. Materials used consisted of (a) 60 cases of Hypertension in whom ECG were analysed in details and who included 13 cases having left ventricular strain pattern ECG, (b) 58 cases with left ventricular strain pattern and (c) 32 cases with right ventricular strain pattern. In addition to this also studied were 8 cases with the mitral stenosis having upright T waves in V₁ V₂ or V₃ and 9 cases of congenital heart anomalies having upright T waves in V₁, V₂ or V₃ The result of this study is as follows : (1) As to the age factor, the lartest fraction of the patients with left ventricular strain pattern belonged to the age-stratum of 50-70; the largest fraction of the cases with right ventricular strain pattern belonged to that of 30-50. (2) As to the relative incidence of underlying diseases, the group of left ventricular strain pattern consisted of cases with hypertension (45.5%), cases with valvular diseases (22.4%), and cases with cardiovascular syphilis (15.8%); the incidence of arteriosclerosis with- out hypertension was relatively low. The group of right ventricular strain included cases with mitral valvular diseases (56.2%), cases with congenital heart anomalis (18.7%), those with pulmonary diseases (12.5%) and those of syphilis (12.5%). (3) As to the blood pressure factor, the left ventricular strain pattern did not necessarily correlate with the systolic blood pressure, although it occurred often in cases of hypertension. Neither did it correlate with the diastolic pressure, mean blood pressure or venous pressure. While the right ventricular strain pattern was often associated with somewhat increased right ventricular systolic pressure, (right ventricular) end-diastolic pressure, (right ventricular) mean pressure, mean pulmonary artery pressure and pulmonary "capillary" pressure above normal, the elevation of these pressures above normal was not necessarily associated with the inverted T wave ; that is to say, the right ventricular strain pattern did not bear a direct relationship with these pressures. Elevated above a certain limit, these pressures became closely correlatable with the incidence of the right ventricular strain pattern. In short, the incidence of the ventricular strain pattern ECG bears a certain relationship, but not a direct pathogenetical one, with the systemic or intraventricular pressures.