Objective: Myocardial deformation has been proposed as a means for quantifying dobutamine stress echocardiography (DSE). However, myocardial deformation may be influenced by other processes including left ventricular hypertrophy (LVH). This study sought to investigate the effect of LVH on myocardial deformation at DSE.Methods: DSE and coronary angiography was performed within 6 months on 126 individuals, all with normal resting LV function. LV mass was calculated from resting images according to the American Society of Echocardiography (ASE) guidelines and indexed to height (m2.7) (LVMI). Left ventricular hypertrophy (LVH) was designated as LVMI ≥ 51 g/m2.7. Automated deformation analysis was undertaken at rest and peak stress within 18 myocardial segments and then the mean calculated. IHD was designated by a maximal lumen diameter stenosis of >50% measured by quantitative coronary angiography.Results: Analysis of those with (+, n = 23) and without (−, n = 103) LVH, and with (+, n = 71) and without IHD (−, n = 55), showed no significant difference in resting end-systolic strain (Ses) but a significant (p < 0.05) reduction in peak Ses and increase in change in Ses (peak Ses minus resting Ses). Division of the population into 4 groups by the presence and/or absence of LVH and/or IHD showed a significant difference in the peak Ses and change in Ses between the groups (p < 0.01, ANOVA). The Ses response was reduced by LVH and IHD, with a significant difference between the LVH(−) IHD(−) group and the other 3 groups (all p < 0.05).Conclusion: LVH and IHD both influence the myocardial deformation response during DSE. The presence of LVH needs to be considered in identifying ischaemia at DSE. Copyright © 2008 Published by Elsevier Ltd. on behalf of The Australasian Society of Cardiac and Thoracic Surgeons and The Cardiac Society of Australia and New Zealand.