Initial effects of the left ventricular repair by plication may not last long in a rat ischemic cardiomyopathy model

Background-Long term effects of left ventricle (LV) repair surgery (LVR) fo r ischemic cardiomyopathy are not well understood. Methods and Results-Sixty-nine rats developed ischemic cardiomyopathy with large akinetic LV area 4 weeks after the left anterior descending artery wa s ligated. In a second surgery 4 weeks later, 33 rats underwent LVR by plic ation of the akinetic LV area (LVR group), and 36 underwent rethoracotomy a lone (sham group). No medication was used in either group. All rats survive d the second surgery. LV end-diastolic dimension as measured by echocardiog raphy, LV fractional shortening, and the maximal end-systolic pressure-volu me relationship (E-max) as calculated from the data by catheter-tipped mano meter and echocardiography improved in the LVR group after the second surge ry, but LV end-diastolic dimension and E-max gradually deteriorated as time passed. LV end-diastolic pressure improved 1 week after LVR but rose signi ficantly 4 weeks after LVR. Brain natriuretic peptide mRNA was lower in the LVR group than in the sham group 1 week after LVR but not 4 weeks postoper atively. Conclusions-Initial improvement in LV function and neurohormonal status aft er LVR did not last for 4 weeks in this rat model when untreated medically. The mechanism of deterioration should be elucidated to improve long-term r esults of LVR.