Arora R R, Horowitz S F, Machac J, Goldman M E
Cathet Cardiovasc Diagn. 1986;12(4):240-5. doi: 10.1002/ccd.1810120408.
Mitral valve prolapse has been associated with septal to aortic root angle abnormalities determined by echocardiography. Thallium 201 imaging in the anterior view permits visualization of the left ventricular long axis. In the present study, the vertical angle was defined as the angle formed by the long axis of the left ventricle and a horizontal line. The vertical angle was determined in 25 patients who had 201 TL stress testing and M-mode echocardiography. Group I (11 patients) had mitral valve prolapse and group II (14 patients) did not have mitral valve prolapse. The vertical angle and ultrasound were read blinded to each other. Height, weight, and body surface area were compared for the two groups, and receiver operator curve analysis performed. Vertical angle measured by TL 201 was significantly more vertical in patients with mitral valve prolapse. Receiver operator curve analysis showed that an angle of greater than 30 degrees successfully identified 9/11 patients with mitral valve prolapse, with a sensitivity of 82% and a specificity of 79%. There were no significant differences in height, weight, or body surface area between the two groups. Thus, patients with mitral valve prolapse have more vertically positioned hearts than patients without mitral valve prolapse, independent of body habitus. The different appearance of a vertically oriented heart may contribute to false-positive readings of TL 201 images.
二尖瓣脱垂与经超声心动图测定的室间隔至主动脉根部角度异常有关。前位铊201显像可显示左心室长轴。在本研究中，垂直角度定义为左心室长轴与水平线所形成的角度。对25例接受铊201负荷试验和M型超声心动图检查的患者测定垂直角度。第一组（11例患者）有二尖瓣脱垂，第二组（14例患者）无二尖瓣脱垂。垂直角度测量值与超声检查结果相互保密。比较两组患者的身高、体重和体表面积，并进行受试者操作特征曲线分析。铊201测定的垂直角度在二尖瓣脱垂患者中明显更垂直。受试者操作特征曲线分析显示，大于30度的角度成功识别出9/11例二尖瓣脱垂患者，敏感性为82%，特异性为79%。两组患者的身高、体重或体表面积无显著差异。因此，二尖瓣脱垂患者的心脏位置比无二尖瓣脱垂患者更垂直，与体型无关。垂直方向心脏的不同表现可能导致铊201图像出现假阳性读数。
