Abstract: A method of preparing a gene expression prediction profile for distinguishing ischemic and nonischemic cardiomyopathy comprises the steps of obtaining clinical specimens from patients suffering from ischemic or nonischemic cardiomyopathy, isolating nucleic acid sequences from at least a plurality of said specimens, obtaining a gene expression level corresponding to each individual of said nucleic acid sequence by a gene expression profiling method, identifying genes having differences in gene expression by comparing the gene expression level of an ischemic specimen with the gene expression level of a nonischemic specimen, and identifying a gene expression prediction profile comprises genes identified as having differences in gene expression so that said prediction profile distinguishes ischemic and nonischemic cardiomyopathy.