Echocardiographic features of accessory mitral valve tissue presenting left ventricular outflow tract obstruction in a dog

Abstract

In a 3-year-old Samoyed, aortic bulging was found on radiography during a general check-up. On echocardiography, turbulent flow was found in left ventricular outflow tract (LVOT) with high velocity (6.1 m/s). A linear structure was attached to the interventricular septum and connected to the chordae tendineae reaching the papillary muscle. A part of the structure moved during cardiac cycle, similar to mitral motion. This dog was diagnosed with LVOT obstruction caused by accessory mitral valve tissue (AMVT). This is the first report of AMVT in veterinary medicine. AMVT should be considered as a possible cause of LVOT obstruction in dogs.

Left ventricular outflow tract obstruction caused by a congenital accessory mitral valve leaflet and treated by open‐heart surgery in a young dog

“…Patients with an AMVL may be asymptomatic, but the possibility of signs associated with LVOTO (i.e., dyspnea, chest pain, syncope) or complications from the AMVL itself (i.e., risk of infective endocarditis and thromboembolism) has been reported. In veterinary medicine, an adult dog with accessory mitral valve tissue causing LVOTO was reported (Kim et al 2021). Although the case in this previous report presented with an abnormal structure similar to ours, the dog was lost to followup before the effect of medical treatment was evaluated.…”

“…In veterinary medicine, an adult dog with accessory mitral valve tissue causing LVOTO was reported (Kim et al . 2021). Although the case in this previous report presented with an abnormal structure similar to ours, the dog was lost to follow‐up before the effect of medical treatment was evaluated.…”

“…Accessory mitral valve leaflet can, however, be an incidental finding in asymptomatic adults, suggesting it can have a benign course (Manganaro et al 2014). In veterinary medicine, only one dog with accessory mitral valve tissue causing LVOTO has been reported, without any follow-up information (Kim et al 2021). The case reported here is a young Shetland sheepdog with LVOTO caused by a congenital AMVL and treated by open surgical resection in conjunction with mitral valve plasty.…”

“…In veterinary medicine, only one dog with accessory mitral valve tissue causing LVOTO has been reported, without any follow‐up information (Kim et al . 2021). The case reported here is a young Shetland sheepdog with LVOTO caused by a congenital AMVL and treated by open surgical resection in conjunction with mitral valve plasty.…”