Kuijpers N W, Szatmári V
Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 10o8, 3584 c M, Utrecht, the Netherlands.
Tijdschr Diergeneeskd. 2011 May 1;136(5):326-31.
A 6-month-old male European shorthair cat was examined because of a 2/6 systolic left apical cardiac murmur. Echocardiography revealed severe concentric left ventricular hypertrophy and severe dynamic left ventricular outflow tract obstruction (pressure gradient of 85 mmHg) caused by systolic anterior motion (SAM) of the septal mitral valve leaflet. After 2 months of oral treatment with atenolol, the cardiac murmur had disappeared. Echocardiography showed only slight thickening of the interventricular septum and resolution of the pressure gradient. The cat was discharged and its owner was advised to continue atenolol lifelong. Echocardiographic findings of a combination of left ventricular concentric hypertrophy and dynamic left ventricular outflow tract obstruction can be caused by hypertrophic obstructive cardiomyopathy (HOCM) or mitral valve dysplasia in the absence of hypertension and fixed aortic stenosis. In the case of HOCM, left ventricular hypertrophy is the primary process. In the case of mitral valve dysplasia, systolic anterior motion of the mitral valve is the primary problem, which leads to dynamic left ventricular outflow tract obstruction and ultimately to left ventricular concentric hypertrophy, due to pressure overload. If the left ventricular outflow tract obstruction is reduced with an oral beta-receptor blocker the secondary left ventricular hypertrophy may resolve. This would not happen in the case of hypertrophic obstructive cardiomyopathy. To the best of the authors' knowledge, this is the first documented case of severe dynamic left ventricular outflow tract obstruction and severe left ventricular hypertrophy in a cat successfully treated with oral atenolol.
一只6个月大的雄性欧洲短毛猫因2/6级收缩期左心尖部心脏杂音接受检查。超声心动图显示严重的同心性左心室肥厚以及严重的动态左心室流出道梗阻（压力阶差为85 mmHg），由二尖瓣隔叶收缩期前向运动（SAM）引起。口服阿替洛尔治疗2个月后，心脏杂音消失。超声心动图显示仅室间隔轻度增厚且压力阶差消失。这只猫出院了，并建议其主人终身继续服用阿替洛尔。左心室同心性肥厚和动态左心室流出道梗阻并存的超声心动图表现，在无高血压和固定性主动脉瓣狭窄的情况下，可能由肥厚性梗阻性心肌病（HOCM）或二尖瓣发育异常引起。在HOCM病例中，左心室肥厚是主要病变过程。在二尖瓣发育异常病例中，二尖瓣收缩期前向运动是主要问题，由于压力负荷过重，导致动态左心室流出道梗阻并最终引起左心室同心性肥厚。如果口服β受体阻滞剂能减轻左心室流出道梗阻，继发性左心室肥厚可能会消退。而在肥厚性梗阻性心肌病病例中则不会出现这种情况。据作者所知，这是第一例有记录的猫严重动态左心室流出道梗阻和严重左心室肥厚经口服阿替洛尔成功治疗的病例。
