Background and aim of the study: Non-compaction cardiomyopathy (NCCM) is a disorder characterized by loosened, spongy myocardium associated with a high incidence of heart failure and systemic embolization. The mitral annulus (MA) is an important component of the mitral valve apparatus, and plays a role in left ventricular and left atrial function. The study aim was to use real-time three-dimensional echocardiography (RT3DE) in the assessment of MA size and function in patients with NCCM.
Methods: The study comprised the following patient populations: 20 patients with an established diagnosis of NCCM; 20 with an established diagnosis of dilated cardiomyopathy (DCM); and 16 control subjects. RT3DE was used to measure MA annulus diameter, MA fractional area change (MAFAC(3D)) and MA fractional shortening (MAFS(3D)).
Results: The left ventricular ejection fraction (LVEF) in NCCM patients (38.0 +/- 18.3%) was higher than in DCM patients (18.0 +/- 4.1%), but lower than in controls (56.9 +/- 9.2%) (p <0.05). The prevalence and severity of mitral regurgitation were comparable in the NCCM and DCM groups, but higher than in controls (p <0.05). The MA area was significantly larger, while MAFAC(3D) and MAFS(3D) were significantly impaired in NCCM patients compared to controls. Both, in systole and diastole, the MA diameter and area were larger in DCM than NCCM patients, but no difference was observed in MAFAC(3D) and MAFS(3D). The number of non-compacted segments did not correlate with MA diameter and area, MAFAC(3D) and MAFS(3D). MAFAC(3D) was significantly correlated with LVEF in NCCM (r = 0.43, p <0.05) and in DCM (r = 0.47, p <0.05).
Conclusion: Mitral annulus enlargement and functional impairment were both present in NCCM patients, with a higher incidence and severity of mitral regurgitation.