Development of left ventricular hypertrophy in a novel porcine model of mitral regurgitation

AbstractObjectives. We aimed to develop a porcine model for chronic nonischemic mitral regurgitation (MR) to investigate left ventricular (LV) enlargement and eccentric hypertrophy. Design. Nonischemic MR was induced in 30 pigs by open-chest immobilization of the posterior mitral leaflet by transannular traction sutures that where applied in transmyocardial fashion. A sham operated control group (n = 13) was included. Echocardiographic LV size and heart weight assessed at euthanasia were used to evaluate the development of LV enlargement and eccentric hypertrophy after 8 weeks follow-up. Results. Eight pigs died and seven were excluded due to mediastinal infection (n = 2) or failure to produce MR (n = 5). Thus, 28 pigs were included and were divided into three groups: controls (n = 12), mild MR (mMR; n = 10), and moderate to severe MR (sMR; n = 6). The change in LV internal diameter in diastole (LVIDd) from baseline to follow-up was significantly higher in the sMR group compared to that of the control gro...