Usefulness of left ventricular conic index measured by real-time three-dimensional echocardiography to predict left ventricular remodeling after acute myocardial infarction.

Early identification of left ventricular (LV) remodeling after acute myocardial infarction (AMI) is of clinical importance. The predictive value of real-time 3-dimensional echocardiography (RT-3DE) for LV remodeling after AMI is unknown. We prospectively studied 62 patients with AMI who underwent RT-3DE at baseline (72 +/- 5 hours) and 1 month and 6 months after AMI. LV remodeling was defined as a >20% increase from baseline in LV end-diastolic volume (LVEDV) at 6 months. At 6 months, 20 patients (32%) with and 42 (68%) without LV remodeling were identified. Patients with remodeling showed increased LVEDV, from 112.6 +/- 17.2 to 138 +/- 31 ml (p <0.001), and decreased LV ejection fraction (LVEF), from 0.50 +/- 0.07 to 0.44 +/- 0.10 (p <0.01). Changes in LVEDV from baseline to 6-month follow-up were positively correlated with peak creatine kinase-MB, LVEDV, LVEF, wall motion score, deceleration time of E wave, LV sphericity index (LVEDV divided by the volume of a sphere whose diameter is the LV end-diastolic long axis), and LV conic index (LVEDV divided by the volume of a cone whose bottom diameter is the internal diameter of the mitral annulus and height is the LV long axis). LV conic index at baseline was found to be the best predictor of LV remodeling, with a sensitivity and specificity of 100% and 90.9%, respectively, and a cut-off value of >3.87. In conclusion, LV conic index measured by RT-3DE in the early phase after AMI can accurately predict LV remodeling over 6-month follow-up.