Abstract 18477: Left Ventricular Ejection Fraction is Not Sensitive Enough to Accurately Determine Timing of Surgical Referral for Asymptomatic Patients With Chronic Mitral Regurgitation
The current clinical guidelines for asymptomatic patients with chronic MR, utilize EF to trigger surgical referral. We hypothesize that 1) EF is not sensitive enough to detect the earliest contractile injury in chronic MR and 2) injury associated with chronic MR is not global but rather heterogeneous, occurring regionally and predictably, and prior to the onset of global left ventricular (LV) dysfunction.
Asymptomatic: patients with chronic MR and normal left ventricular EF by echocardiography (n=14) underwent cardiac MRI with tissue tagging. The point-specific comparison (at 15,300 LV grid points) of multiple strain parameters to a 60-patient normal human strain database allowed normalization of patient-specific regional contractile function. Data was color-contour mapped over patient-specific 3D geometry, then further averaged across six LV regions (anterior, anterolateral, posterolateral, posterior, posteroseptal, anteroseptal).
Global: LV function by multiparametric strain analysis was normal for all 14 MR patients when compared to normal controls. Despite overall preserved global LV function, the LV septum demonstrated significantly worse normalized contractile function when compared to other regions of the LV (0.07 ± 0.42 vs -0.40 ± 0.54, p=0.009 ). Hyper-contractile regions (lateral walls) appeared to compensate (p=0.002) for the reduced septal contractile function thereby masking injury detection by global indices. In asymptomatic MR patients with normal global LV function, contractile injury is heterogeneous, with a consistent distribution pattern identifying the LV septum as being injured earliest with contractile compensation by other regions. Rather than relying upon global LV contractile metrics, which does not detect early onset of injury, asymptomatic chronic MR patients should be followed with surveillance of early injury (or “sentinel”) LV regions (LV septum) with high-resolution metrics of regional contractile function.
- © 2013 by American Heart Association, Inc.