Abstract 2074: Global systolic Left Ventricular Circumferential and Longitudinal Strain and Strain Rate in Dobutamine Stress Echocardiography
Objective: Strain (S) and Strain Rate (SR) are new techniques for assessment of systolic function of Left Ventricle (LV). Speckle tracking has been used to assess the segmental S and SR of the LV. Global LV systolic S and SR may be helpful to assess patients with Ischemic Heart Disease (IHD) and Cardiomyopathies. Our objective was to assess the change in global longitudinal and circumferential S and SR during Dobutamine Stress Echocardiography (DSE) in patients who had normal stress echocardiograms.
Methods: Digitally stored images of 41 patients with normal DSE (normal regional wall motion at rest and with stress) were analyzed using Syngo Velocity Vector Imaging (VVI) software (Siemens Medical Solutions). No patient had significant valve disease or a history of IHD. Short axis (SAX) and apical 4-chamber (A4C) views were analyzed at rest, 10 (low dose) and 40mcg/kg/min (peak dose). Global circumferential and longitudinal S and SR were obtained by averaging the S and SR of the different segments in SAX and A4C views at each stage.
Results: The mean age was 64 ± 13 yrs. Ejection fraction was 64 ± 4%. The group achieved 85 ± 10% of predicted maximum heart rate. In the SAX view, the global circumferential S increased from −21.69% at rest to −23.61% at low dose (p<.04). From rest to peak, the S increased from −21.69% to −25.01% (p<.006). No significant increase was seen from low to peak dose (p<.19). There was a significant increase in global circumferential SR in SAX from rest to low dose (p<.0007), rest to peak (p<.0001) and low dose to peak (p<.0003). The global longitudinal S in A4C increased significantly from rest to low dose (p<.0014), but not from rest to peak or low dose to peak. The global longitudinal SR in A4C increased significantly from rest to low dose (p<.0006), from low to peak dose (p<.0025) and from rest to peak (p<.0001)
Conclusions: Global circumferential and longitudinal S showed a significant increase from rest to low dose, but not from low to peak dose. This suggests that the ionotropic effects of Dobutamine are more important at lower doses whereas at higher doses, the chronotropic effects predominate. Global S and SR may have an incremental value in the interpretation of DSE in patients with IHD and cardiomyopathies and may serve as an index to assess LV systolic function.