Abstract 223: Ventricular Dys-synchrony by Real-Time Three-Dimensional Echocardiography as a Determinant of Functional Mitral Regurgitation Independent of Global and Regional Geometry After Acute Myocardial Infarction
Background: Left ventricular (LV) dys-synchrony after myocardial infarction (MI) is associated with functional mitral regurgitation (FMR) and worse prognosis. However, to what extent these findings are related beyond traditional LV geometry has not been well characterized.
Method: RT-3DE was performed on 30 normal volunteers and 64 cases (age: 64 years; female: 30%) experiencing acute MI. MR Severity was assessed by vena contracta method with at least moderate degree considered as significant. Dys-synchrony index (DI) was derived from the dispersion of time to minimum regional volume for all LV segments. Multivariate logistic regression and receiver-operating curve (ROC) was used to test the clinical value of LV dys-synchrony beyond global and regional (mitral tenting) geometry in the identification of significant MR.
Results: Compared with normal control group, patients with acute MI had significantly higher global DI (1.3±0.6 vs 3.2±2.5%, p<0.01) and lower EF (63±7.1 vs 49.9±12, P<0.01). DIs based on 12 (apex-excluded) or 16 segments model were all significantly correlated with FMR severity even after adjusting for age, LVEF and EDV (p<0.01). The addition of 12 and 16 segments DI on global and regional geometry increased ROC in the discrimination of high-degree FMR significantly (Figure⇓).
Conclusion: Dys-synchrony superimposed on LV geometric alterations provided the best model relating to FMR severity after MI. Our results suggest that an integrated information of both dys-synchrony and geometry may have a better understanding of FMR pathophysiology and, may thus help provide specific interventions to the treatment of FMR complicating MI.