Left Ventricular Structure and Function for Postmyocardial Infarction and Heart Failure Risk Stratification by Three-dimensional Echocardiography

Accurate risk stratification by left ventricular (LV) ejection fraction (EF) is essential for treatment of patients with myocardial infarction (MI) or those with heart failure (CHF), because of its high prognostic value. This would permit aggressive targeting of therapy in these populations, in whom morbidity and mortality are high. Cardiac magnetic resonance (CMR) and computed tomography (CT) are expensive, not widely available, and impractical for following up large numbers of patients. Cardiac catheterization (CATH) and multigated radionuclide angiography (MUGA) are either invasive or require use of radioactive tracers. Echocardiographic (ECHO) methods are used extensively because they are inexpensive, widely available, and easily repeated. M-mode ECHO methods are simple but of limited value because they do not account for the marked variability in LV size and shape in patients with MI and CHF. Two-dimensional (2D) ECHO improves LV sampling, but does not capture the complexity of the LV size and shape in this population. It is associated with high measurement variability as a result of lack of spatial registration of images and use of invalid geometric assumptions. Three-dimensional (3D) ECHO methods (real time [RT] and freehand [FH]) have been shown previously to overcome limitations associated with both M-mode and 2DECHO. Although they correlate well to gold standards such as CMR in heterogeneous populations with a wide range of EFs, these results may not be extrapolated to patients with post-MI and CHF in whom the EF is both depressed and narrower in range, and where regional wallmotion abnormalities are prominent. The role of 3DECHO in the post-MI and CHF population, how-