Background: Noncompaction cardiomyopathy (NCCM) is a rare disorder with persistance of the embryonic pattern of myoarchitecture. NCCM is characterized by loosened, spongy myocardium associated with a high incidence of systolic and diastolic left ventricular (LV) dysfunction and heart failure (HF). It is known that LV dysfunction contributes to elevated left atrial (LA) and pulmonary vascular pressures, however atrial function has not been examined in NCCM. The objective of the present study was to assess LA systolic function characterized by LA ejection force (LAEF) in NCCM patients using real-time three-dimensional echocardiography (RT3DE) and to compare to control subjects.
Methods: The study comprised 17 patients with an established diagnosis of NCCM and their results were compared to 17 healthy age-matched controls with no evidence of cardiovascular disease. Forty-one percent of NCCM patients were in NYHA functional class II / III HF. Previously proposed echocardiographic diagnostic criteria for NCCM were used. All patients underwent conventional two-dimensional echocardiography and RT3DE. LAEF was measured based on MA annulus diameter (LAEF 3D-MAD) and area (LAEF 3D-MAA) using RT3DE.
Results: The presence and severity of mitral regurgitation were more frequent in NCCM patients than in control subjects. LV diameters and mitral annulus were significantly increased in NCCM patients. Compared with control subjects, both LAEF 3D-MAD (3.8 +/- 2.2 vs 2.3 +/- 1.0 kdyne, P < 0.05) and LAEF 3D-MAA (12.7 +/- 7.6 vs 4.9 +/- 2.1 kdyne, P < 0.01) were significantly increased in NCCM patients.
Conclusions: LAEF as a characteristic of LA systolic function is increased in NCCM patients compared to normal individuals. These results can suggest compensating left atrial work against the dysfunctional LV in NCCM patients.