1. A computer implemented method for cardiac segmentation, comprising the steps of: providing a plurality of digitized medical images, each said image comprising a plurality of intensities corresponding to a domain of points on an 2-dimensional grid, said plurality of images comprising a sequence of cardiac images acquired at different time points; for each image, selecting a set of candidate points for the inner and outer boundaries of the myocardium and connecting points in said inner boundary and connecting points in said outer boundary with piecewise continuous polynomial functions, wherein selecting a set of candidate points for the inner and outer boundaries of the myocardium further comprises, for each boundary, detecting a set of edge points; initializing a circle whose radius is computed either from a result of a preceding image, or for a first image according to a position of a bottom left myocardium boundary, varying circle parameters around said initial circle, and using said edge points to vote for a best circle of fitting; and segmenting said myocardium in each image from a region of points between said boundaries, wherein said steps of providing a plurality of digitized medical images, selecting a set of candidate points, connecting points in said inner and outer boundaries, and segmenting said myocardium in each image are performed by a computer processor.