Development of acute ischemic heart failure in sheep

The goal of the present study was to develop a large animal model of acute ischemic left ventricular heart failure (LVHF) that can be used to assess t he influence of the PUCA pump on the heart and circulatory system under rea listic conditions. We tested the hypothesis that mild stenosis of the coron ary artery in combination with mild ventricular pacing induces an acute hea rt failure condition, whereas the separate phenomena themselves do not lead to impaired heart function. Mean aortic pressure (AoP), left ventricular e nd-diastolic pressure (LVEDP), stroke volume (SV) and myocardial systolic s hortening (MSS) were compared 30 minutes after a pacemaker (PM) induced tac hycardia in anaesthetized sheep (n=3) without and with +/- 50% stenosis of the proximal LCx. All parameters measured restored to basic levels when ste nosis was absent When the LCx was partially occluded, mild PM-induced tachy cardia resulted in decreased AoP (P=0.045) as well as in decreased SV (P=0. 048); the LVEDP remained high (P=0.002). Also the recovery of MSS was impai red when stenosis was present (P=0.002). These values indicate that acute h eart failure conditions were present. The technique used proved to be safe and allowed fine-tuning of the demand ischemia by adapting heart frequency to the required heart failure conditions. The model can be used to study th e effect of LV mechanical support during acute heart failure conditions.