USEFULNESS OF THE RIGHT VENTRICULAR ECHOGRAM : RECORDING TECHNIQUE AND ITS CLINICAL APPLICATION
In order to investigate the best way of recording the right ventricular wall (RVW) by echocardiography and to assess its clinical usefulness, the following study consisted of four parts were performed. First, the best way of recording the RVW were investigated in 40 consecutive adult subjects with normal hearts and with various congenital and aquired cardiac disorders. The recordings of the RVW were taken in five ways, namely, anterior-supine approach with a 2.25 MHz or a 5.0 MHz transducer, subxiphoid approach with a 2.25 MHz transducer and anterior-sitting approach with a 2.25 MHz or a 5.0 MHz transducer. The highest successful recording rate (80%) was obtained by an anterior approach in supine position with a 5.0 MHz transducer. In the second part of the study, the normal range of the RVW thickness by the best way was investigated in 25 out of another 32 normal adults. The normal thickness of the RVW was 2.4 ±0.5 mm (mean ± 1 SD), and the RVW thickness index was 1.7 ±0.2 mm/m2 (mean ± 1 SD). In the third, the validity of recording the RVW by the best way was assessed. The RVW thickness of another 21 patients with right ventricular overload ranged from 2.5 mm to 16 mm, and seemed to have a good correlation with pulmonary arterial systolic pressure (r= +0.77). In the last part of the study, echocardiographic examination was performed in 15 patients with hypertrophic cardiomyopathy, 7 patients with severe hypertension, 15 patients with mild hypertension and 20 normal subjects, in order to find out the most useful indices in differentiating hypertrophic cardiomyopathy from hypertensive heart disease. The thickness of the left ventricular posterior wall (LVPW) and the interventricular septum (IYS) with a 2.25 MHz transducer, and of the right ventricular anterior wall (RYAW) with a 5.0 MHz transducer were measured at end-diastole. The ratio of IVS to LVPW, RVAW to LVPW and RYAW to IVS were also calculated. The thickness of RVAW was the most useful index in differentiating hypertrophic cardiomyopathy (4.5 ±0.2 mm [1 SD])from severe hypertension (2.8 ±0.4 mm) and mild hypertension (2.7 ±0.3 mm) (p<0.01). Thus an anterior approach with a 5.0 MHz transducer would be the best way of recording the RVW, and be clinically quite useful.