Left atrial functional reserve in patients with nonischemic dilated cardiomyopathy: an echocardiographic dobutamine study.

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 (O(2)max) was measured; the day after, a low-dose dobutamine (5 to 10 micro g/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] x 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 O(2)max values (r = 0.73 and r = 0.71, respectively; p < 0.001). After inotropic stimulation, LAEV and LAEF were increased in patients with O(2)max values > 14 mL/kg/min (5.62 +/- 7.28 mL and 10.04 +/- 13.13%, respectively) and decreased in patients with O(2)max 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.