Effect of age and heart rate on atrial mechanical function assessed by Doppler tissue imaging in healthy individuals.

Background: The potential usefulness of Doppler tissue imaging (DTI) to assess atrial mechanical function in cardiac disease has been demonstrated. However, there are few reports on normal values of atrial function by DTI analysis.

Methods: Echocardiography with color-coded DTI was performed in 131 healthy control subjects. The peak atrial contraction velocity (V(A)) and the timing of mechanical events were assessed offline at the left atrial (LA) and right atrial (RA) free wall and interatrial septum.

Results: V(A) was higher in the RA (9.0 +/- 2.6 cm/s) than the LA (7.5 +/- 2.4 cm/s, P < .001), and both sites were higher than the interatrial septum (5.6 +/- 1.3 cm/s, both P < .001). The interatrial delay was 24 +/- 21 milliseconds. V(A) at the LA was higher in the participants aged 60 years or older than those who were younger than 60 years (8.1 +/- 2.7 vs 6.7 +/- 1.4 cm/s, P < .001), as was the velocity at the RA (9.6 +/- 2.8 vs 8.0 +/- 2.1 cm/s, P < .01). V(A) at the LA was higher in the participants with heart rate of 60/min or higher than those with lower heart rate (7.9 +/- 2.5 vs 6.8 +/- 1.8 cm/s, P < .05). Sex difference had no effect on V(A) and timings of atrial events.

Conclusions: Assessment of atrial mechanical function by DTI is feasible in healthy individuals. The V(A) is the highest at the RA, followed by LA, and the lowest at the interatrial septum. Older age and faster heart rate seems to augment V(A) in the atrial walls.