CHAPTER 4: FUNCTIONAL ANATOMY OF THE HEART

BACKGROUND

The study of the heart and great vessels has expanded since the days of Andreas Vesalius, the great 16th-century anatomist who recognized the impact of anatomy on the practice of medicine. During the European Renaissance, the tomographic approach to the study of cardiac anatomy became popular because of its artistically based correlations. This is vividly depicted in the drawings of Leonardo da Vinci¹ (Fig. 4–1), the first comparative anatomist since Aristotle (see Chap. 1). During the ensuing nearly 400 years, however, interest in cardiac anatomy was very sporadic and limited to a few zealous and pioneering physicians, anatomists, and artists. The 19th century ushered in the era of anatomic dissection for the study of physiologic and pathophysiologic processes, and correlations. Virchow in 1885 described the inflow-outflow method of cardiac dissection, which followed the direction of blood flow.² It was quick and simple and became the dissection method of choice. The works of Virchow and Osler paved the way to understanding the pathophysiologic basis of such diseases as pulmonary embolism, endocarditis, and heart failure.² Renewed interest in the study of cardiac anatomy and pathology was facilitated by the rise in autopsy rates in Europe and North America during the first half of the 20th century.³ Herrick described the clinical features of coronary thrombosis.³ Later, Blumgart, Schlesinger, and Zoll advanced our understanding of coronary artery disease through elegant clinicopathologic correlations.³

These achievements notwithstanding, however, were limited to postmortem examinations. The advent of cardiac surgery in the 1950s, followed by coronary angiography, was a major impetus for promoting the study of in vivo clinicopathologic anatomic correlations. Although cardiac surgeons were quick to appreciate the importance of having a detailed understanding of cardiac anatomy, clinical cardiologists were more interested in pathophysiology. However, with the introduction of noninvasive imaging techniques (echocardiography, computed tomography [CT], magnetic resonance imaging [MRI], and single photon-emission computed tomography [SPECT]) over the past three decades, the perception of cardiac anatomy and pathophysiology radically changed for all of medicine in general and cardiology in particular.

With increasing use of tomographic techniques in the diagnosis and management of cardiovascular diseases, there has been a corresponding decrease in the use of autopsy for anatomic correlations. The reasons for this decrease are complex and controversial and include an increased confidence in antemortem laboratory and imaging technologies, and rescinding the mandate for autopsies for hospital accreditation.² Nonetheless, autopsy still uncovers unexpected processes in upward of 40% of cases and remains an invaluable tool for quality assurance and educational programs.