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Evidence linking arsenic exposure to the prevalence of cardiovascular disease is limited but increasing. Most data collected thus far has used urine or blood as biomarkers of arsenic exposure, however these offer short term exposure data. Toenails have been increasingly used as a biomarker of longer-term exposure as they have been shown to have a significant association with arsenic in drinking water (r=0.854 p=0.000). A high-throughput method was developed for use in epidemiological studies for the analysis of arsenic metabolites by HPLC-ICPMS and total elements by ICP-MS in nails from one sample solution. This method was utilised to measure 4000 human nail samples from a case/control study in Bangladesh which is the first epidemiological study to investigate the potential relationships between arsenic metabolites in toenails and the occurrence of CVD, in this case, myocardial infarction. An additional method was validated for use in epidemiological studies using a PrepFAST IC coupled with ICP-MS (PrepFAST ICICPMS). Inorganic arsenic (iAs) was found to be the dominant species in the nail samples with a mean value of 1.03mg/kg and a mean % value of total arsenic of 85.5%. Organic arsenic species DMA and MMA were present in lower concentrations with mean values of 0.06 and 0.08mg/kg and 7.6 and 7.0% of total arsenic, respectively. Analysis of the case/control data revealed statistically significant higher median values in cases for DMA, %DMA, and SMI (0.034, 6.5%,0.95) compared to controls (0.031, 5.7%, 0.84) for all samples. Significant differences in total element and arsenic metabolite data between subsets of toenails and finger/toenail mixes, with the addition of different metabolites and elements displaying different significances within the different subsets has provoked the need for a paired finger and toenail study to better understand the metabolism and distribution of arsenic so results can be better interpreted.