In healthcare, we refer to the heart and blood vessels using the words cardiac and cardiovascular. These terms are derived from the Greek word kardiakos which means "pertaining to the heart."1 Most often, heart or cardiac in a healthcare context is used in reference to the organ or organ system; however, individuals in our society also commonly use the word when they talk about the heart of the matter, speak about not having the heart to give bad news, describe a new acquaintance as an individual after our own heart, thank another from the bottom of our hearts, or despair when our favorite sports team loses heart and goes down to defeat. There are numerous other common idioms about the heart, such as when we put our heart into an activity, we set our heart on a goal, or we describe a friend as one who has his or her heart in the right place. And yet, we instantly understand these expressions about the heart. The idioms we casually use today developed over time as our understanding of the heart and its functions evolved.
The human heart has been a focus of fascination for philosophers and scientists and ordinary people throughout recorded history. In early civilizations, the heart was considered to be the seat of thought, reason, emotion, as well as the location of the soul; thus, many of our idioms refer to these beliefs. Ancient Egyptians weighed the heart after death and compared this to the weight of a feather to determine whether an individual was eligible for entry into the afterlife, whereas Aztecs offered the heart from sacrificial victims to preserve the power of the sun and protect themselves from the wrath of particular deities. Although a number of Egyptian, Greek, and Roman scientists studied the heart, arteries, and veins and theorized about these structures, William Harvey first provided an accurate description of the pumping function of the heart and circulatory system in 1628.2 Although Harvey determined that the heart functioned as a pump for the circulatory system and valves ensured that the flow was one way, these premises were not well accepted for years. With a greater understanding of the structure and function of the cardiovascular system came the desire to evaluate and identify normal and abnormal structure and function and eventually the knowledge and ability to intervene and improve the outcome that we have today. Our current abilities are often based on decades or even centuries of questioning and inquiry.
Early descriptions of evaluation of the pulse can be found in Egyptian and Chinese records.3 The Greek physician Hippocrates offered the first published description of sudden cardiac death,4 and Galen, another famous Greek physician, identified the heart's need for a continuous supply of nutritive substrate for energy metabolism.5 Over the succeeding centuries, as the heart and circulatory system became more clearly understood, scientists and healthcare providers developed mechanisms for the evaluation of cardiovascular function that included physical examination techniques, capture of electrical activity, measurement of vascular pressures, analysis of cardiac biomarkers, and hemodynamic evaluation by invasive and noninvasive means. The genesis for many of our current evaluation techniques may be traced to previous centuries. For example, Emil du Bois-Reymond6 described in 1843 the action potential as electrical activity that accompanied muscular contraction. Currently, virtually all cardiovascular healthcare providers are able to evaluate the electrocardiogram with some level of expertise, and we have the capacity to capture and transmit this information via wireless technology to a distant site for evaluation.
During the previous century and a half, there has been an explosion of knowledge and techniques for the evaluation of cardiovascular function. The development of the electrocardiogram by Einthoven, the identification of Kortkoff sounds that became the basis of the auscultory method of measuring blood pressure, and the first catheterization of the right part of the heart by Forssmann all led to further refinement of these techniques and adoption in clinical practice. As clinicians, we would not dream of providing quality care for our patients without data from these evaluation techniques!
This rapid explosion of knowledge about cardiovascular structure and function as well as the technology to measure a wide variety of cardiovascular parameters has been driven by the prevalence and incidence of cardiovascular diseases in our society. Many techniques such as the use of echocardiography begin as novel ideas that were accepted by a small group of supporters, and over time, these evolved into the standard of care7; others such as the pulmonary artery catheter were immediately embraced and became ubiquitous in the management of patients with cardiovascular disease.8 Thus, this issue of the Journal of Cardiovascular Nursing is focused on the evaluation of cardiovascular status. Some of these techniques will be very familiar; others may be new and innovative but may evolve over time into the new gold standard for care of cardiovascular patients. In the spirit of those pioneers who first thought to feel the pulse and use that information to make judgments about required patient care, I would like to offer you this collection of papers focused on the physiological evaluation of cardiovascular status.
"Each generation of scientists stands upon the shoulders of those who have gone before." - Dr. Owen Chamberlain
Susan K. Frazier, PhD, RN
Associate Professor, College of Nursing
University of Kentucky, Lexington
[email protected]
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