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

Abstract

Aims: 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).

Methods and results: 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.

Conclusions: 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.