Optimal left ventricular diameter measurement in subjects with sigmoid septum: comparison with three-dimensional left ventricular volume.

Background: The purpose of this study was to determine the most appropriate measurement of left ventricular (LV) end-diastolic diameter for subjects with the sigmoid septum (SS) by measuring the LV end-diastolic diameter at the base and mid-ventricle and by examining the relationship between these measurements and the three-dimensional (3D) echocardiographic LV end-diastolic volume.

Methods: In 91 patients who underwent echocardiography for screening cardiovascular abnormalities, the aorto-septal angle (ASA) was measured as an index of the sigmoid septum. LV end-diastolic diameter was measured at the base and mid-ventricular level (DD and DD, respectively), and their average value was calculated (DD). By using 3D echocardiography, LV end-diastolic volume (EDV) was measured.

Results: Among 91 patients, 48 patients had narrow ASA (< 120 degrees) and were divided into the sigmoid septum (SS) group, and the remaining 43 patients were divided into the non-SS group. In the SS group, all DD, DD, and DD were significantly correlated with EDV (r = 0.59, 0.80, and 0.76, respectively), and the correlation coefficient between DD and EDV was significantly lower than that between DD and EDV (p < 0.01). On the other hand, in the non-SS group, all DD, DD, and DD were significantly correlated with EDV (r = 0.77, 0.85, and 0.84, respectively), and the correlation coefficient between DD and EDV was statistically comparable to that between DD and EDV (p = 0.12). ASA was significantly correlated with the difference of DD minus DD (r =  - 0.71, p < 0.001).

Conclusions: In patients with SS, DD and DD were well reflected the 3D echocardiographic LV end-diastolic volume.