Cardiovascular diseases (e.g., vascular diseases, strokes, heart failure) reach epidemic proportions in the elderly and are the primary limits to survival in man. Age-associated changes in heart structure and function represent the major risk factors in heart failure (HF) syndromes and are associated with altered patterns of gene expression that can generally be seen as relative changes in the abundance of gene transcripts. An understanding of the molecular mechanisms underlying these changes should be tantamount to defining a genetic basis for aging; however, the analysis of processes as complicated as aging requires an accounting of biological diversity. Until recently, most of the changes in transcript abundance were identified one at a time, but the advent of gene expression arrays has permitted rapid, large-scale expression profiling. This has provided information about the dynamics of total gene expression, which can be used to identify pathways and elucidate regulatory events that may be affected during senescence or in response to disease. Importantly, very large sample sizes or meta-analyses of studies of smaller sample sizes should be sufficient to account for the diversity of altered gene expression that directs alterations in specific molecular pathways, which underlie changes in cardiac structure and function in senescence and disease.