1. A computer implemented method for measuring ventricular dimensions from M-mode echocardiograms, the method performed by the computer comprising the steps of: providing to a computer a digitized M-mode echocardiogram image comprising a plurality of intensities associated with a 2-dimensional grid; running a plurality of local classifiers, wherein each local classifier trained to detect a landmark on either an end-diastole (ED) line or an end-systole (ES) line in said image, and recording all possible landmarks detected by said classifiers, wherein a search range in an N-dimensional parameter space defined by said landmarks for each dimension is reduced into a union of subsets containing said possible landmark detection, wherein each dimension of said parameter space corresponds to one of the plurality of landmarks; for each combination of possible landmarks, checking if an order of the possible landmarks is consistent with a known ordering of said landmarks; and if said order is consistent, running a global detector on each consistent combination of possible landmarks to find a possible landmark combination with a highest detection probability as a confirmed landmark detection, wherein said landmarks are used for measuring ventricular dimensions.