Chronic subtoxic cadmium and/or lead ingestions from dietary sources are suspected etiologic factors contributing to cardiovascular system dysfunction and pathology. The proposed study represents a continuation of an ongoing multidisciplinary research program which has examined functional, metabolic, and structural changes in cardiovascular system associated with chronic ingestion of environmental heavy-metal pollutants. The proposed investigations will apply the proven techniques of electrocardiographic, His bundle electrographic and cardiac contractility analyses, as well as, 31P-NMR spectroscopic analyses of cardiac, hepatic and renal metabolites. Recent studies have detected biologically significant, pathological changes in tissues (heart, liver, kidney) from cadmium (Cd) and/or lead (Pb) exposed animals. Complementary studies of cardiac morphology with emphasis on subcellular metal distributions determined by electron-microprobe microanalytical methods to examine structural, metabolic and functional intercorrelations are proposed. The proposed method of exposing (drinking water) the experimental animals (rats) to the heavy metals permits control of intake and simulates human routes of oral exposure at concentrations which are relevant to the general population. Environmental stressors which exhibit subtle cardiotoxic effects, and thereby contribute to the deterioration of the heart pose significant health problems. Evidence demonstrating compromised cardiac function and metabolism induced by chronic heavy metal exposures suggests that life-time Cd and/or Pb exposure contribute to the development of degenerative cardiovascular disease states. To further investigate this association of chronic heavy metal exposures with cardiovascular disease, interdisciplinary studies concerned with concentration (0.1 or 1 ppm Cd and/or Pb) and temporal relationships (6, 12 or 18 month exposures) are proposed utilizing the established rat model described.