Dilated Cardiomyopathy: Normalized Multiparametric Myocardial Strain Predicts Contractile Recovery

Abstract

Left ventricular contractile injury in dilated cardiomyopathy (DCM) may occur in a consistently heterogeneous distribution, suggesting that early-injury sentinel regions may have prognostic significance. Heightened surveillance of these regions with high-resolution contractile metrics may predict recovery in DCM. Multiple three-dimensional strain parameters were calculated at each of 15,300 left ventricular grid points from systolic displacement data obtained from cardiac magnetic resonance imaging in 124 test subjects. In 24 DCM patients, Z-scores for two strain parameters at each grid point were calculated by comparison of patient-specific strain values to respective point-specific mean and standard deviation values from a normal human strain database (n= 100). Multiparametric strain Z-scores were averaged over six left ventricular regions at basilar, mid, and apical levels (18 subregions). Patients with DCM were stratified into three groups on the basis of a blinded review of clinical contractile recovery (complete, n= 7; incomplete, n= 7; none, n= 10). Basilar-septal subregions were consistently heavily injured. Basilar-septal Z-scores were significantly larger (worse) than those for the rest of the left ventricle (2.73 ± 1.27 versus 2.22 ± 0.83; p= 0.011) and lateral wall (2.73 ± 1.27 versus 1.44 ± 0.72; p < 0.001). All patients with sentinel region average multiparametric strain Z-scores less than two standard deviations (n= 6) experienced complete recovery, whereas 17 of 18 DCM patients with Z-scores greater than two standard deviations experienced incomplete or no contractile recovery. Contractile injury in DCM is heterogeneous, with basilar-septal regions injured more than lateral regions. The targeting of early-injury sentinel regions for heightened surveillance with high-resolution metrics of microregional contractile function may accurately predict recovery on medical therapy. A two standard deviation Z-score threshold may predict contractile recovery.