Quantification of low-dose dobutamine stress using speckle tracking echocardiography in coronary artery disease

We sought to evaluate the utility of speckle tracking echocardiography (STE) for detecting left ventricular (LV) mechanical abnormalities during low-dose (20 microg) dobutamine stress (DSE).

Twenty-nine patients (56 +/- 12 years) with a history of recent acute coronary events (ACE) underwent STE-DSE. Left ventricular images, sampled at frame rates 70-100 Hz, were analysed off-line (Echopac BT 6.0.0). Velocity, strain, and rotational imaging were performed. Twenty patients had LV ejection fraction (EF) >40% (Group 1) whereas nine patients had LVEF <40% (Group 2). Average heart and frame rates were identical during DSE in the two groups (P = ns). Global circumferential strain (%) was significantly lower in Group 2 compared with Group 1 (10.65 +/- 5.30 vs. 16.82 +/- 6.61; P < 0.05) at rest and during peak stress (14.72 +/- 6.51 vs. 21.13 +/- 7.2; P < 0.05). The global peak rotation rate (degree/s) was, however, higher at rest in Group 2 (70 +/- 97 vs. 19 +/- 67; P < 0.05) and 20 microg stress. Peak systolic velocity increased in three of the four LV walls at 20 microg (in Groups 1 and 2). A global rotational rate increased significantly at 20 microg during systole in both the groups, but was unchanged in Group 2 during diastole.

Speckle tracking echocardiography dobutamine stress appears to provide comprehensive information on LV mechanical status in the aftermath of ACE. The modality may help risk stratify such patients.