Objective: To evaluate left atrial functional reserve in patients with chronic heart failure and nonischemic dilated cardiomyopathy (DCM).
Background: Left ventricular functional status has been investigated using echocardiographic dobutamine.
Methods: In 35 consecutive patients (29 men and 6 women; mean ± SD age, 42.37 ± 13.5 years), peak oxygen consumption (V̇o2max) was measured; the day after, a low-dose dobutamine (5 to 10 μg/kg/min, of 5 min each step) study was performed. Left atrial volumes at mitral valve opening, onset of left atrial systole, and mitral valve closure were measured by using two-dimensional echocardiography. Left atrial active emptying volume (LAEV) [volume at onset of atrial systole − minimal volume] was calculated, as was left atrial active emptying fraction (LAEF): [(volume at onset of atrial systole − minimal volume)/volume at onset of atrial systole] × 100. The changes (values obtained after inotropic stimulation minus those obtained at baseline) of the above-mentioned echocardiographic variables were considered as left atrial functional reserve.
Results: In the entire study group after dobutamine infusion, increases in LAEV (3.34 ± 7.54 mL, p = 0.01) and LAEF (6 ± 13.2%, p = 0.01) were observed. The changes in the above-mentioned parameters were correlated with V̇o2max values (r = 0.73 and r = 0.71, respectively; p < 0.001). After inotropic stimulation, LAEV and LAEF were increased in patients with V̇o2max values > 14 mL/kg/min (5.62 ± 7.28 mL and 10.04 ± 13.13%, respectively) and decreased in patients with V̇o2max values < 14 mL/kg/min (− 1.08 ± 6.13 mL and − 1.6 ± 9.9%, respectively; p = 0.01 for both).
Conclusion: Echocardiographic dobutamine can evaluate left atrial functional reserve in patients with nonischemic DCM.