Toxic chemicals in the environment are known to produce a wide array of adverse effects in the heart and cardiovascular system. These harmful effects include hypertension, peripheral vascular injury, alterations of lipid levels, disturbances of cardiac rhythm, cardiomyopathy, acute myocardial infarction (MI), stroke, and sudden death. Toxic chemicals are also linked to cardiovascular disease risk factors, including obesity, insulin resistance, the metabolic syndrome, and diabetes. This chapter describes these effects.1
Beyond the known cardiotoxins, there likely are other chemicals in the modern environment whose toxicity to the heart and cardiovascular system has yet to be recognized. These cardiotoxins will be discovered among the tens of thousands of new synthetic chemicals invented and produced in the past half century. The majority of these materials have not been tested for toxicity, which is a serious failure of stewardship by the chemical industry and the US federal government.2,3 These synthetic chemicals are widely disseminated in the human environment, and national surveys conducted by the Centers for Disease Control and Prevention (CDC) find measurable levels of several hundred synthetic chemicals in the blood and urine of virtually all Americans.4
Given the continuing potential today for exposure to new chemicals of unexamined toxicity, every physician is advised to obtain a brief history of occupational and environmental exposure from every patient and to ask more detailed follow-up questions or seek consultation with a specialist in occupational and environmental medicine if the initial screen raises suspicion of toxic exposure. Straightforward screening algorithms have been developed.5 The most intense exposures typically occur in occupational settings, and most discoveries of new associations between toxic chemicals and disease have been made by physicians examining working populations.6 The possibility of etiologic discovery is high.
Cardiovascular disease caused by toxic agents in the environment is preventable. Prevention requires diagnostic recognition of the links between exposure and disease followed by evidence-based interruption of exposure.7
Lead is a heavy metal, a chemical element that comprises 0.002% of the Earth's crust. It has a low melting point, is easily molded and shaped, and can be combined with other metals to form alloys. Because of these properties, lead has been used by humans for millennia and is used today in products as diverse as pipes, storage batteries, pigments, glazes, vinyl products, weights, shot and ammunition, cable covers, and radiation shielding. From the 1930s to the 1970s, lead was used extensively as a gasoline additive to improve engine performance.8 Lead is widespread in the modern environment. Global consumption of lead continues to increase mainly because of rising demand for large and small batteries.9
Patients may be exposed to lead by either inhalation or ingestion. Inhalation is the most common route of adult exposure and the most serious exposures occur among workers exposed occupationally.10 Workers at greatest risk include smelter and foundry workers, hazardous waste ...