Lessons for Cardiovascular Clinical Investigators: The Tumultuous 2,500-Year Journey of Physicians Who Ignited Our Fire.

Whereas medical practice stems from Hippocrates, cardiovascular science originates with Aristotle. The Hippocratic philosophy was championed by Galen (129-216 CE), whose advocacy of a tripartite soul found favor in the early Christian Church. In contrast, Aristotle's works were banned as heresy by ecclesiastical authority, only to survive and prosper in the Islamic Golden Age (775-1258 CE). Galen theorized that the circulation consisted of separate venous and arterial systems. Blood was produced in the liver and traveled centrifugally through veins. When arriving in the right ventricle, venous blood passed through tiny pores in the ventricular septum into the left ventricle, where it became aerated by air passing from the lungs through the pulmonary veins to the left side of the heart. Following arrival at distal sites, arterial blood disappeared, being consumed by the tissues, requiring that the liver needed to continually synthesize new blood. The heart was viewed as a sucking organ, and the peripheral pulse was deemed to result from changes in arterial tone, rather than cardiac systole. Galen's framework remained undisputed and dominated medical thought for 1,300 years, but the reintroduction of Aristotelian principles from the Islamic world into Europe (through the efforts of the Toledo School of Translators) were nurtured by the academic freedom and iconoclastic environment uniquely cultivated at the University of Padua, made possible by Venetian rebellion against papal authority. At Padua, the work of Andreas Vesalius, Realdo Colombo, Hieronymus Fabricius ab Acquapendente, and William Harvey (1543-1628) methodically destroyed Galen's model, leading to the modern concept of a closed-ended circulation. Yet, due to political forces, Harvey was ridiculed, as was James Lind, who performed the first prospective controlled trial, involving citrus fruits for scurvy (1747); it took nearly 50 years for his work to be accepted. Even the work of William Withering (1785), the father of cardiovascular pharmacology, was tarnished by professional jealously and the marketing campaign of a pharmaceutical company. Today's cardiovascular investigators should understand that major advances are routinely derided by the medical establishment for political or personal reasons; and it may take decades or centuries for important work to be accepted.