Abstract 11275: Paradoxical Interventricular Septal Motion Predisposes to Late Gadolinium Enhancement of Ventricular Insertion Points in Pulmonary Hypertension
Background: Late gadolinium enhancement (LGE) of ventricular insertion points (VIPs) is a finding commonly seen on magnetic resonance imaging (MRI) in pulmonary hypertension (PH) (Figure, left). Despite the high prevalence of this observation, the underlying mechanisms and predisposing factors are poorly understood. We hypothesized that dyssynchronized motion of the interventricular septum (IVS) predisposes to LGE of VIPs, and examined correlations between LGE mass volume and indices of right heart catheterization (RHC), MRI, and echocardiography.
Method: Subjects comprised 34 consecutive patients diagnosed with PH who underwent RHC. Mean pulmonary arterial pressure (mPAP) was 38±9 mmHg. LGE mass volume was calculated by tracing the LGE area on MRI. Radial displacement of the left ventricular (LV) wall was assessed by speckle-tracking echocardiography at the level of the mitral valve chordae. For quantitative evaluation, we defined outward displacement [a=a1(anterior IVS) + a2(inferior IVS)] and inward displacement [b = b1(anterior IVS) + b2(inferior IVS)] of IVS, and calculated paradoxical motion index (PMI: a/a+b) (Figure, right).
Results: LGE in VIPs was observed in 32 patients (94%), and the mass volume ranged from 0 to 50.0 ml (mean ± standard deviation, 19.6 ± 14.3). Significant correlations with LGE on VIPs were observed for mPAP (r=0.48, p=0.0052) and MRI-derived parameters (right ventricular (RV) mass index (r=0.63, p<0.0001), RV end-diastolic volume index (r=0.68, p<0.0001), and RV ejection fraction (r=-0.64, p<0.0001). Notably, PMI also showed significant correlations with LGE mass volume with the highest correlation coefficient (r=0.70, p<0.0001).
Conclusion: Paradoxical interventricular motion may be a novel factor that predisposes toward the development of LGE in VIPs among patients with PH.
- © 2011 by American Heart Association, Inc.