Shakespeare wrote about it before modern medicine had even considered the possibility. Romeo dies believing that Juliet has passed away, and Juliet takes her own life upon finding Romeo’s lifeless body. There is no prior injury, no infection, and no coronary obstruction that would explain this outcome from the perspective of modern biology — only a succession of loss, despair, and emotional collapse. That scene has been read and interpreted countless times as a literary tragedy; today, cardiology and neuroscience are debating whether, in some cases, the line separating poetic metaphor and human biology is more blurred than it seems.

The so-called “broken heart syndrome” demonstrates that extreme emotional distress does not kill instantly like a lightning strike, but it can trigger a series of biological cascades capable of pushing the heart to its limit and increasing the risk for death in some patients.

Takotsubo syndrome, better known as “broken heart syndrome” or stress-induced cardiomyopathy, is a form of sudden acute heart failure — generally transient — characterized by apical akinesis of the left ventricle that can mimic a myocardial infarction. It was first described in 1990 by the Japanese physician Hikaru Sato and was named “takotsubo” — a term referring to the pots used to catch octopuses in Japan — due to the shape the affected ventricle takes on during systole in imaging tests. Takotsubo syndrome is no longer considered a benign and transient condition; rather, it can have real consequences for the heart, including a fatal outcome.

Patients with this condition typically present with chest pain, shortness of breath, and ECG abnormalities such as ST-segment changes and/or T-wave inversion, but without the coronary obstruction typical of a heart attack. The most common trigger is an episode of intense emotional stress, such as the loss of a loved one, a romantic breakup, or an extreme life situation. It primarily affects older women with comorbidities and can be associated with a significant in-hospital mortality rate.

From the Brain to the Heart

For years, it was considered a benign and reversible condition; however, recent studies have shown that it is a disorder that can be associated with heart failure and other serious complications that can lead to the patient’s death, both in the short and long term.

One of the most important advances in recent years has been the consolidation of the so-called brain-heart axis, where the most widely accepted hypothesis holds that a situation of intense emotional stress abnormally activates brain circuits involved in emotional regulation and the autonomic nervous system, triggering a neurohormonal release capable of altering cardiac function.

Supporting this explanation are neuroimaging studies that have detected alterations in the functional connectivity of brain networks involved in emotional processing and autonomic control in patients with Takotsubo syndrome. This disruption, reported in a study published in the journal Neurology (2024), suggests that the origin of the problem lies not solely in the heart but in the way the brain regulates the response to that emotional stress.

The findings of this study indicate that the lesions causing Takotsubo cardiomyopathy correspond to a brain network defined by functional connectivity with the vagal nucleus, a region of the brain involved in the parasympathetic nervous system’s control of the heart. This approach changes our understanding of the disease and opens the door to new therapeutic strategies that also target the nervous system, rather than just the heart.

Specifically, this brain alteration may contribute to a poorer prognosis for the disorder, as evidenced by a multicenter study from the German Italian Spanish Takotsubo Registry (GEIST) published in Journal of the American College of Cardiology in 2025. This study found that beta-blockers were associated with reduced mortality during patient follow-up, although they did not reduce recurrences of the syndrome.

Grief as a Trigger

Although Romeo and Juliet ultimately took their own lives, the trigger for both deaths lay in their inability to cope with life without the company of their beloved. This intense grief is one of the most common causes of Takotsubo syndrome. Recent epidemiologic evidence shows that it is also associated with an increased risk for cardiovascular disease and overall mortality, especially in the first days and weeks following the loss.

A Danish study published in Frontiers (2025) analyzed how different trajectories following a natural death relate to long-term health and concluded that those who experience severe and persistent symptoms of grief — in addition to making more frequent visits to the doctor — had higher mortality rates for up to 10 years after the loss.

The study, conducted on more than 1700 people, revealed that 6% developed a pattern of intense and persistent grief associated with greater use of healthcare resources over the years. In addition, they consumed more healthcare resources, reported higher use of antidepressants (5.63 times more), sedatives, and anxiolytics (2.60 times more), and had an 88% higher risk for death than the group with mild grief symptoms.

The authors, in addition to noting that intense and sustained loss affects emotional well-being, warn of the prolonged healthcare burden it causes and question whether current healthcare services are adequately meeting the needs of these individuals.

What Happens in a ‘Broken Heart’

From a physiologic standpoint, intense grief activates multiple stress response systems. There is sustained activation of the sympathetic nervous system, with increased heart rate, blood pressure, and the release of catecholamines such as adrenaline. At the same time, changes in inflammatory markers and alterations in immune regulation have been observed.

This set of responses may contribute to the onset of acute cardiovascular events in vulnerable individuals, especially those with preexisting cardiovascular disease or advanced age. The period of highest risk appears to occur precisely during the early stages of grief, when the physiologic burden of stress is most intense.

To diagnose the syndrome, specialists look for established criteria such as transient abnormalities in left ventricular motion, characteristic changes on the ECG, and elevated cardiac biomarkers, while ruling out significant coronary artery disease and other conditions that can produce similar symptoms.

In short, the most recent comparative analyses have shown that long-term mortality from Takotsubo syndrome can be comparable to that observed after a myocardial infarction, and that heart failure is one of the main associated complications; therefore, the risk is not limited to the initial acute episode, and clinical follow-up must be considered.

RETAKO Registry in Spain

Spain has played a prominent role in research on Takotsubo syndrome. A national analysis based on the minimum basic dataset from 2008 to 2021 identified nearly 12,952 hospitalizations, with a progressive increase in cases over time, from 210 in the first year evaluated to 1918 in the last. According to this study, in-hospital mortality stood at around 7%, confirming the clinical significance of the syndrome within the healthcare system.

The Spanish contribution has also been particularly significant due to the creation of the REgistry of TAKOtsubo syndrome (RETAKO) registry, which demonstrated years ago that this syndrome frequently occurs following emotional stress and primarily affects women going through menopause. Furthermore, several Spanish centers are actively participating in GEIST, an international multicenter network that is helping to clarify which treatments can reduce mortality and which patients are at higher risk of complications.

When Emotion Affects Biology

In conclusion, the accumulated evidence suggests that extreme emotion can act as a biological trigger in vulnerable individuals. There is a clear relationship between intense emotional stress and certain acute cardiovascular abnormalities associated with an increased risk for mortality in specific clinical cases.

Takotsubo syndrome represents the most obvious manifestation of this connection between emotions and cardiovascular function. This does not mean that anyone going through grief is at a risk for dying of a broken heart, but it does mean that many factors can influence the outcome, such as age, preexisting conditions, the intensity and duration of stress, and each individual’s social and healthcare context.

Shakespeare turned death by love into one of literature’s most universal images; four centuries later, science has confirmed that emotions can leave a significant mark on the body. These marks do not always break the heart or condemn those who are grieving, but the pain they cause, under certain circumstances, can trigger mechanisms capable of putting the body to the test.

This story was translated from El Medico Interactivo, part of the Medscape Professional Network.