The dramatic surge in heart disease deaths during the 20th century may have environmental roots that challenge conventional thinking about cardiovascular risk. While medical orthodoxy focuses on cholesterol, blood pressure, and lifestyle factors, mounting evidence suggests lead contamination played a pivotal role in creating the modern coronary epidemic. Historical medical records reveal that angina was relatively rare in William Osler's era, yet physicians already recognized chronic lead poisoning as a driver of arterial hardening. The transformation of heart disease from uncommon condition to America's leading killer coincided precisely with the industrial combustion age and widespread adoption of leaded gasoline. Lead operates through multiple cardiovascular pathways, promoting inflammation, oxidative stress, and endothelial dysfunction while disrupting normal calcium metabolism in arterial walls. Unlike traditional risk factors that require decades to manifest, lead accumulates in bone tissue and continues leaching into circulation throughout life, creating persistent low-grade toxicity. Recent epidemiological analyses suggest that even blood lead levels previously considered safe correlate with increased cardiovascular mortality. This paradigm challenges the assumption that heart disease epidemics are inevitable consequences of modern prosperity. Environmental lead remediation efforts, including gasoline phase-outs, may partially explain declining cardiovascular death rates in developed nations since the 1970s. However, ongoing exposure through old paint, contaminated soil, and industrial sources maintains cardiovascular risk, particularly in disadvantaged communities. Recognition of lead's role suggests that comprehensive heart disease prevention requires addressing environmental toxins alongside conventional interventions, potentially offering new therapeutic targets for populations with elevated exposure histories.