Evaluation of left atrial mechanical function and atrial conduction abnormalities in patients with isolated bicuspid aortic valve

OBJECTIVE
Present study is an evaluation of left atrial (LA) mechanical and conduction function in patients with bicuspid aortic valve (BAV) without significant valve dysfunction, and an investigation of relationship between LA function and aortic elasticity.

METHODS
Study population consisted of 34 isolated BAV patients (mean age: 34±13 years) and 29 healthy, age- and sex-matched volunteers (mean age: 30±10 years). LA volume was measured using biplane area-length method and LA active and passive emptying volume and fraction was calculated. Intra- and interatrial atrial conduction time (ACT) was measured with tissue Doppler imaging. Aortic elasticity parameters were calculated including aortic strain, aortic stiffness index, aortic distensibility, and aortic elastic modulus.

RESULTS
LA diameter, LA maximum volume, LA volume before atrial systole, and LA active emptying fraction were significantly higher in patients with BAV (33.2±3.2 mm vs 34.9±2.8 mm, p=0.030; 16.2±4.6 mL/m2 vs 19.8±4.8 mL/m2, p=0.004; 10.2±3.7 mL/m2 vs 12.1±4.9 mL/m2, p=0.029; and 30.4±12.0% vs 39.9±11.8%, p=0.003, respectively). ACT was similar between groups. Aortic distensibility was significantly lower and aortic stiffness index and aortic elastic modulus were significantly higher in patients with BAV (8.1±4.6 [10-6cm2dyn-1] vs 5.1±3.6 [10-6cm2dyn-1], p=0.006; 4.1±2.8 vs 7.3±4.9, p=0.003; 3.6±2.8 [dyn.cm-2106] vs 5.9±3.9 [dyn.cm-2106], p=0.010, respectively). In correlation analysis, LA active emptying fraction was significantly correlated with aortic stiffness index and mitral A- velocity (r=0.431, p<0.001; r=0.304, p=0.016, respectively).

CONCLUSION
Present study demonstrated that LA mechanical function and aortic elasticity parameters were disrupted, while atrial conduction time was preserved in patients with isolated BAV. Furthermore, LA mechanical function parameters were significantly correlated with aortic elasticity parameters and mitral inflow A-wave.