Mathematical modelling to identify patients who should not undergo left ventricle remodelling surgery.

A mathematical model was developed to predict the cardiac output post left ventricle volume reduction surgery (LVVRS) to establish who should not undergo surgery. Two scenarios were evaluated: dilated cardiomyopathy (DCM), and left ventricular wall aneurysm (LVA). In DCM, a left ventricular diastolic volume (LVDV) of 380 ml, ejection fraction (EF) of 15%, and a heart rate of 80, produces a cardiac output of 4.5 l/min. After LVVRS for DCM to reduce the LV volume to 315 ml, the EF is unchanged, but the cardiac output drops by 0.7 l/min. In LV aneurysms, a LVDV of 380 ml, EF of 15%, and a heart rate of 80, produces a cardiac output of 4.5 l/min. After LVVRS for LVA reducing the LV volume to 320 ml, the EF increases to 56%, and the predicted cardiac output doubles. LVVRS is potentially very hazardous in the setting of DCM, confirmed by the international registry report and the Surgical Treatment for Ischemic Heart Failure Trial. However, in the setting of LVA, the surgery can result in marked improvement in cardiac output. The effect on postoperative cardiac output, due to the extent of LV resection can potentially be modelled for preoperatively.