The outbreak of the American Civil War in 1861 meant new challenges for the medical doctors treating the wounded on both sides of the conflict. But with these new challenges came timely new developments to help diagnosis and treatment of injured soldiers. This included morphine, the hypodermic needle and the stethoscope.
Being able to listen to a patient's heart meant a new appreciation of how the heart worked and, to some extent, how it didn't. Though the heart was recognized primarily as a muscle that pumped blood, old notions about the heart being the centre of emotion and personality in humans had not been completely forgotten by the mid-19th century. Physicians already recognized that strong emotion could affect heart activity but, rather than simply relying on patient description of how stress affected them, physicians could listen to the heart directly and draw their own conclusions. Conflicting ideas of what a heart actually did came into play during the Civil War as doctors began monitoring the vital signs of soldiers under combat conditions. It was through studying soldiers that three physicians independently described what would be known as the "Irritable Heart Syndrome" or more simply as "Soldier's Heart."
Early reports of Soldier's Heart began in 1862 following the first attempt of the Army of the Potomac to invade Virginia. If the soldiers expected an easy victory, they quickly learned otherwise as Robert E. Lee's Confederate troops managed to beat them back and eventually forced a retreat. The shock of this defeat was a major blow to Northern confidence and the high casualty rate, including wounded soldiers who were simply abandoned as the army withdrew, added to the number of dead. With defeat after defeat at Antietam and Fredericksburg came more casualties and physicians began noting unusual symptoms among the soldiers being treated.
Along with battlefield injuries and diseases such as malaria, dysentery, and typhoid, army physicians also observed severe heart palpitations in the soldiers who had survived combat. According to one physician, Alfred Stille, the soldiers themselves attributed the strange symptoms to the rigourous campaigning, including long marches with heavy backpacks. Based on his own observations, Stille concluded that the palpitations were due to "a state of extreme exhaustion, especially when produced by prolonged and violent muscular effort." Other physicians reported on the "cardiac muscular exhaustion" seen in soldiers and expanded on what Stille was observing. Henry Hartshorne described what he was seeing as "soldier's heart exhaustion." Specific symptoms included a rapid, feeble pulse rate, an abnormally fast heart rate (even when the solder was at rest), and breathing problems. Hartshorne argued that the symptoms were caused by overexertion, lack of rest, and poor nutrition though he was careful to distinguish the new syndrome from ordinary nervous exhaustion.
The name most commonly associated with the irritable heart syndrome seen in soldiers was Jacob Mendes Da Costa who was the first physician to link the symptoms he was observing to psychological factors. The condition he described is often called Da Costa's Syndrome in his honour. Essentially, he regarded the condition he was seeing in patients as a "cardiac neurosis" since "the mass of cardiac disorder is not organic, but functional. And of these again a very large proportion belong to the group which I have designated 'irritable heart'" Since there was no physical signs of actual heart disease involved, the symptoms themselves represented the condition he needed to treat. Along with the heart symptoms, soldiers were also describing "jerking during sleep" , disturbed sleep, and nightmares. While Da Costa was careful not to label the new syndrome as being a mental disorder, he did insist that the condition was not easily faked (even then, military authorities were wary of possible malingers). He also acknowledged that the condition was being seen more frequently in soldiers as the war dragged on, however. Treatment with conventional heart medications such as digitalis showed little real effect.
After the war ended, Da Costa continued writing about the condition which he saw in civilian patients as well. He maintained that the symptoms could be caused by any significant strain which, among other things, could mean emotional shock. Many of the case histories he presented described how his syndrome could develop even in non-soldiers. Based on his cases, Da Costa wrote:
We can understand how even mental emotion, acting through the nervous system on the nerves of the heart, may produce real trouble, and how the worry of life, and strain on the feelings, when long kept up, may give rise to conditions which, in figurative language, we call “heart-weary,” and “heart-sick,” and which, not as a figure of speech, but in truth, may be the beginning of actual cardiac malady.
Da Costa also suggested that irritable heart symptoms could be caused by anything that resulted in overexertion of the heart including sexual disorders, abuse of tea or coffee, irregularity or excess in eating or drinking or, "long matrimonial engagements." In other words, virtually anything that caused nervous irritability could cause irritable heart syndrome. For treatment, Da Costa recommended rest about all else though he also advocated medication (especially digitalis for the heart). Despite the lack of real evidence that "irritable heart syndrome" actually involved heart disease, Da Costa's based his ideas about the syndrome on patients becoming "heart-weary" due to chronic overexertion.
Though Da Costa and his colleagues came close to realizing the role that traumatic stress could play on the body, they never quite managed to make that final connection. According to Robert Kugelmann, physicians such as Da Costa mainly focused on the role that overexertion and fatigue had on the heart since these were things they could observe directly. Acknowledging the role of psychic factors that could only be inferred likely seemed a step backward. Da Costa described the rigours of combat that soldiers faced as well as lack of sleep, poor nutrition, and exposure to disease. All of these were potential factors for irritable heart syndrome as far as he was concerned. That soldiers were also constantly afraid was something he failed to mention in his writings. Whether because he did not want irritable heart patients accused of cowardice or simply refused to consider other factors besides overwork, Da Costa never wavered in regarding fatigue as the culprit.
And fatigue was certainly a problem in 19th century medicine. In an era before labour legislation or safety regulations, many workers were obliged to work long hours under unsafe conditions we nowadays see only in Third World factories. That many of these workers also developed irritable heart symptoms seemed to prove Da Costa's hypothesis about overwork being the culprit. There were also the inevitable racist comparisons with some ethnic groups deemed to be hardier and less vulnerable to irritable heart symptoms than others. As Roberts Bartholow pointed out in an 1867 Sanitary Commission report on military health, soldiers of Anglo-Saxon descent were the most immune to fatigue. For African-American soldiers, he regarded them as "less enduring than the white soldier; less active, vigilant, and enterprising, and more given to malingering. The Mulatto is feebler than the Negro." As the very bottom of the heap were the Spanish-American soldiers coming from states such as New Mexico who were "cowardly, unreliable, and difficult to control, in consequence of a very mercurial temperament.”
As the memory of the Civil War faded and new wars arose, the Irritable Heart Syndrome gave way to later diagnoses including "shell shock" which became popular during World War I. With each new case, physicians also recognized that it was not a heart sydrome at all. As cardiologist James MacKenzie pointed out in 1916, such cases " were overwhelmingly non-cardiac, the most likely etiology being the strain and exhaustion of life in the trenches superimposed on some 'toxic influence' caused by infection." Once again, physicians were extremely reluctant to attribute the symptoms they were seeing to psychological factors such as acute stress given the stigma attached to anything suggesting that soldiers lacked courage. Though "shell shock" made its introduction as a diagnosis during World War I, it would not be until well after World War II that the devastating impact of posttraumatic stress on soldiers would be grudgingly recognized.
Even today, true diagnosis of the Irritable Heart Disorder symptoms described by Da Costa and other physicians is likely impossible based on the limited information available. Though Posttraumatic Stress Disorder (PTSD) remains the most popular explanation for what Da Costa was describing, physical causes such as poor nutrition and infection cannot be ruled out either. That the horrors of war take a terrible toll on soldiers and civilians caught in the crossfire seems obvious enough now. Recognizing that constant threat of death could lead to "legitimate" medical conditions rather than the type of symptoms associated with "cowardice" would take much longer.