Independent parameters of left atrium function in hypertensive heart disease

The left atrium reservoir function has an important role in the global cardiac performance and is determined by multiple cardiac and extra-cardiac factors. A new parameter is introduced, the independent strain, which quantifies left atrium reservoir phase deformation during isovolumetric relaxation.

Is evaluated whether independent strain can identify intrinsic atrial myocardial damage in hypertension.

Prospective observational study in which echocardiography was done to 50 hypertensive patients and 80 healthy volunteers. Myocardial deformation was evaluated with two-dimensional speckle tracking and left atrium volumes were calculated whit 3D-echocardiography.

In hypertensive patients, the indexed left atrium volume was greater than in the control group (34 ± 7.8 vs 24 ± 4.9 mL/m² ); strain of pump (-5.7 ± 2.4% vs -17±3.5%) and reservoir phases (34 ± 9% vs 48 ± 10%) were worst. The minimum left atrium volume was higher (26 ± 10 vs 15 ± 8 mL) and left atrium independent strain was lower in hypertensive patients (4.0% vs 6.5%, P = .001). Left atrium independent strain only correlated with minimum left atrium volume (r = -.31, P = .048).

The left ventricle longitudinal performance has an important contributing role in the left atrium reservoir function; despite this finding, the independent strain was unrelated to left ventricle longitudinal function.

Independent strain can identify atrial myocyte contractile dysfunction in hypertension given the relative absence of hemodynamic loads during this period. Additionally, quantification of left atrium minimum volume suggests indirectly the presence of atrial myocyte contractile dysfunction.