Cardiac interventional procedures such as myocardial stem cell delivery and radiofrequency ablation require a high degree of accuracy and efficiency. Real-time, 2-D MR technology is being developed to guide such procedures; the associated challenges include the relatively low resolution and image quality in real-time images. Real-time MR guidance can be enhanced by acquiring a 4-D (3-D + phase) volume prior to the procedure and aligning it to the 2-D real-time images, so that corresponding features in the prior volume can be integrated into the real-time image visualization. This technique provides spatial context with high resolution and SNR. A left ventricular (LV) myocardial wall contour tracking system was developed to maintain spatial alignment of prior volume images to real-time MR images. Over 9 test images sequences, each comprising 100 frames of simulated respiratory motion, the tracker maintained alignment with a mean displacement error of 1.61mm in a region of interest around the LV, as compared to a mean displacement error of 5.2mm without tracking.