IN NOVEMBER 2004, my usually energetic mother called to tell me that she was tired. Not just tired, exhausted. She’d begun begging out of social engagements and had even given up her beloved weekly tennis game after one of the women in her foursome complained that she no longer bothered to run in from the baseline. I was concerned, but not about my mother’s physical health. My father had died a few months earlier after a long illness, during which my mother had been his primary caregiver, so of course she was worn out and, after 55 years of happy marriage, grieving deeply. What ailed her, I assumed, was a broken heart.

“Alas,” as Elizabeth Hardwick wrote in her novel, Sleepless Nights, “the heart is not a metaphor, or at least not always a metaphor.” Within weeks after my mother called me about her fatigue, she suffered a massive myocardial infarction. A cardiac catheterization showed near total blockage of her left anterior descending coronary artery. Atherosclerosis, not widowhood, had caused my mother’s lassitude. Ironically, the particular blockage my mother had is so often fatal and so commonly and mistakenly thought of as occurring only in men that it’s known as “the widow-maker.”

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In his beautifully written, informative, and thought-provoking third book, Heart: A History, Sandeep Jauhar, a cardiologist, explores both the metaphorical and biological properties of the heart. He gives a fascinating account of how the heart’s circulatory and electrical system came to be understood over many centuries, ultimately leading to lifesaving innovations such as the heart transplant, the pacemaker, and the implantable defibrillator. He also tells the story of how our concept of the heart evolved from metaphor to machine, an evolution which is still not complete and which, Jauhar argues, probably never will be. Like The Emperor of All Maladies, Siddhartha Mukherjee’s masterful “biography of cancer,” which won the 2011 Pulitzer Prize for General Nonfiction, Heart is a work of both medical history and medical philosophy, one which invites us to look deeply not just at one organ system or category of disease but more broadly at the relationship of mind to body and art to science.

Since ancient times, Jauhar explains, the heart has been considered the seat of emotion, possibly because it is the only organ we can actually sense moving within us, beating faster or more slowly depending on how we feel. Jauhar proposes: “The word ‘emotion’ derives from the French verb émouvoir, meaning ‘to stir up,’ and perhaps it is only logical that emotions would be linked to an organ characterized by its agitated movement.”

Our hearts stop beating when we die, so, also understandably, the heart has long been thought of as the source of life force, the only internal organ the Egyptians believed necessary to carry into the afterlife. Similarly, the acceleration of the heartbeat caused by love (and sex) have made the heart, especially Cupid’s symmetrical twin-mounded version, the symbol of love since the Middle Ages. Centuries after we first appreciated the brain’s vital role in all that makes us human, including cognition, will, and desire, the heart remains entrenched in our language as a metaphor for many human qualities, as Jauhar enumerates:

To “take heart” is to have courage. To “speak from the heart” conveys sincerity. We say we “learned by heart” what we have understood thoroughly or committed to memory. To “take something to heart” reflects worry or sadness. If your “heart goes out to someone,” you sympathize with his or her problems. Reconciliation or repentance requires a “change of heart.”

Further, Jauhar notes, we describe a person’s character according to the supposed physical characteristics of his or her metaphorical heart: big, small, hard, warm, cold, gold, or made of stone. And still further, in moments of deep honesty, hearts are “poured out” and “Your ‘heart of heart,’ as Hamlet tells Horatio, is the place of your most sacred feelings.”

Our belief that the heart is the most essential (as in, “of essence”) human organ is so firmly rooted that, even as our knowledge of anatomy and physiology advanced, we never fully abandoned it. Jauhar writes that William Harvey, who, in the 17th century, first described the circulatory system, feared for his life after suggesting that the lungs and blood vessels, and not only the heart, were vital to life. In the early 20th century, Jauhar argues, the development of the cardiac bypass machine, which provides artificial circulation so that the heart can be stopped during cardiac surgery, was hampered by similar reverence for the heart. “Though an artificial kidney was developed with relatively little fanfare,” Jauhar observes, “the heart occupied a special place in the popular imagination. How could a man-made machine replace the organ that houses the soul?” In 1982, “[W]hen Barney Clark, a retired dentist with end-stage heart failure, received the first permanent artificial heart […] his wife of thirty-nine years asked the doctors, ‘Will he still be able to love me?’”

Mrs. Clark’s question wasn’t based entirely on an archaic understanding of the heart. As Jauhar explains, the heart, in fact, is a repository of emotion in demonstrable and non-metaphorical ways. In addition to the acceleration of heart rate we’ve all experienced when we’re afraid, angry, or excited, we now know that stress, depression, grief, an unhappy marriage, or even a surprise party may all be risk factors for heart disease. Jauhar describes in some detail Takotsubo cardiomyopathy, in which the heart muscle balloons and takes the distinctive shape of a Japanese octopus trapping pot after someone has suffered an acute emotional shock. It’s thought that this deformity may develop because of where stress hormone receptors are located in the myocardium. In any case, Jauhar writes, “In no other condition do the biological and metaphorical hearts intersect so closely.”

Despite the fact that progress in our knowledge of and ability to treat heart disease may have been impeded by, as Jauhar calls them, “cultural fallacies,” amazing progress occurred nonetheless. Jauhar takes us through the development of the heart-lung machine, cardiac catheterization, angioplasty, artificial heart valves, and other wonders. Rather than simply cataloging these innovations, he crafts narratives around them featuring colorful characters. We meet Dr. C. Walton Lillehei, the brilliant and bold Minnesotan, who, in the 1950s, came up with what Jauhar terms “perhaps the most bizarre idea in the history of surgery.” Reasoning that since a pregnant woman’s fetus relies on her circulatory system for its supply of oxygenated blood, Lillehei positioned a teenager and his father side by side and connected their vessels so that the youth’s heart could be stopped and a congenital defect repaired — a crude, in vivo version of cardio-pulmonary bypass (and, as Jauhar points out, an example of how much looser guidelines for informed consent were decades ago). And then there was Werner Forssmann, a young German surgeon whose exploits Jauhar recounts in a chapter aptly titled “Nut.” In 1929, Forssmann convinced a nurse to let him into a locked operating room after hours and, after he’d tied her down so she wouldn’t interfere with his plan, proceeded to cut open his arm, thread a tube into the wound, and pass it through his superior vena cava and into his own heart. He documented these shenanigans with an X-ray image: the first cardiac catheterization.

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Jauhar is a gifted storyteller who paints portraits deftly and with few words. He is a master of the verbal miniature. Here, for example, is how he describes an elderly man with heart failure: “He leaned forward, a bearded, wispy-thin gentleman in a vintage suit whose bowler and neckerchief lent him an arcane, vaudevillian air.” The old man is not a figure in a historical anecdote but, rather, one of Jauhar’s own patients, many of whom appear in Heart along with several members of his family, some of whom have had heart disease. In the prologue of the book, Jauhar reveals that in his late 40s he, too, learned that his coronary arteries were partially occluded, a condition for which people of Indian descent carry increased risk.

Jauhar’s two previous books were memoirs. In Intern: A Doctor’s Initiation and Doctored: The Disillusionment of an American Physician he offered unvarnished accounts of his own medical training and practice, respectively. In the acknowledgments of Heart, Jauhar mentions that his editor frequently reminded him that this new book would be “about the heart, not the heart doctor.” Despite that reminder, Heart is, in fact, very personal. Jauhar reveals that both of his grandfathers and his mother died of coronary disease. He mentions, with regards to his mother, whose diagnosis was, like my mother’s, delayed (with dire consequences) that “one of every two women will develop heart disease in her lifetime, and one in three will die from it, two-thirds with unrecognized symptoms.” Jauhar does not delve into the long and damaging history of gender bias in heart disease diagnosis, treatment, and research, a lacuna in this otherwise comprehensive book.

Jauhar opens each chapter with a personal anecdote, such as his squeamish attempt to perform an experiment on a frog heart in high school and his mother’s pronouncement: “You should do a different experiment, son. Your heart is too small for this.” This opening leads to a discussion of the heart and emotion. There is also a trip to his parents’ home in Fargo, North Dakota, where he accompanies a family friend who is a cardiac surgeon to the operating room. This occasions an account of the early days of open heart surgery, and Jauhar’s truly harrowing recollections of his experience identifying bodies at Ground Zero on the days after 9/11. These, in turn, give him an opportunity to explore the relationship between PTSD and the heart.

Jauhar’s use of milestones in his own life and career as landmarks in this work of medical history might have seemed awkward or even solipsistic in lesser hands. But Jauhar’s engaging prose makes us as happy to spend time with him, his patients, and his family as we are to read about William Harvey or heart transplant pioneer Christiaan Barnard. Moreover, Jauhar’s personal evolution with regard to the heart parallels his profession’s: as a child, he understood the heart as a metaphor, his own queasy heart as “small”; as a young doctor he was, by his own admission, obsessed with the heart as a machine that malfunctioned and needed fixing; now, as a veteran clinician, Jauhar appreciates the heart as an amalgam of metaphor and machine — and something else, too: a mystery.

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My mother didn’t die of her heart attack. Actually, I don’t know what she died of, and neither did any of her doctors. She had several strokes caused by small blood clots that formed in her weakened heart muscle and then traveled to her brain — that much was clear. And the strokes impaired her ability to swallow, so that she was at risk for aspiration pneumonia, which she contracted. In January 2009, her lungs became infected and she needed to be placed on a ventilator. On antibiotics, her pneumonia cleared, and the breathing tube was removed. But my mother didn’t wake up. A CAT scan of her brain showed no new strokes. EKGs showed no further heart damage. Still, she lay asleep, her eyes closed tight, her lips pursed as if, I imagined, in protest. She was transferred to a hospice, and it was there, a week later, that her heart stopped on Valentine’s Day.

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Suzanne Koven is a primary care physician and writer in residence at Massachusetts General Hospital in Boston. Her essays appear in the Boston Globe, VQR, The New England Journal of Medicine, and elsewhere. Her website is www.suzannekoven.com.