In this paper we introduce an improved harmonic phase (HARP) analysis for complementary spatial modulation of magnetization (CSPAMM) tagging of the mouse left ventricular wall, which enables the determination of regional displacement fields with the same resolution as the corresponding CINE anatomical images. CINE MRI was used to measure global function, such as the ejection fraction. The method was tested on two healthy mouse hearts and two mouse hearts with a myocardial infarction, which was induced by a ligation of the left anterior descending coronary artery. We show that the regional displacement fields can be determined. The mean circumferential strain for the left ventricular wall of one of the healthy mice was -0.09 +/- 0.04 (mean +/- standard deviation), while for one of the infarcted mouse hearts strains of -0.02 +/- 0.02 and -0.10 +/- 0.03 were found in the infarcted and remote regions, respectively.