A 74-year-old woman arrived at a British emergency department with chest pain after an emotional shock. Her high-sensitivity troponin peaked at 2232 ng/L against a normal range below 18. Her bedside echocardiogram showed the ballooned apex that defines takotsubo syndrome, with a pumping fraction of 45%, and a CT scan of her coronary arteries found narrowings but nothing obstructive enough to explain the picture. So far, a textbook case of broken heart syndrome, a stress-triggered condition that usually resolves.
A month later, a cardiac MRI came back describing features consistent with apical hypertrophic cardiomyopathy, a genetic disease of thickened heart muscle that carries lifelong implications. Her apex measured 15 millimeters, compared with 7 millimeters at the base. A second MRI three months later agreed. Only a third study, 15 months after she first walked in, showed the thickened segments had completely resolved and pointed back to takotsubo.
Her ECG did not get the memo. Cardiologists at University Hospital Southampton reported in the European Heart Journal Case Reports that her electrocardiographic abnormalities became more pronounced at 15 months and remained present at 2 years.
Swollen Muscle Looks Exactly Like Thick Muscle
The mechanism is straightforward once you see it. Takotsubo floods the heart muscle with fluid. Waterlogged myocardium is bulkier myocardium, and on an imaging slice, bulk is bulk.
The catch is timing. Cardiologists in Lausanne described the trap precisely in The International Journal of Cardiovascular Imaging. Their patient was a 45-year-old woman with deep T-wave inversion whose MRI showed a normal pumping fraction alongside a thickened apex that squeezed shut in systole, a classic apical hypertrophic cardiomyopathy signature. Swelling was also visible at the apex. Two months later, the thickening and the swelling had both vanished, and the tissue measurements had returned to normal.
Their conclusion was blunt: hypertrophy does not reverse, so the apparent thickening had only ever been fluid. They settled on takotsubo caught at a subacute stage, the specific window in which the ballooning and wall-motion abnormality have already resolved, but severe swelling persists. Scan too late, and you miss the ballooning. Scan too early, and you have not yet watched it disappear. A single well-timed scan lands squarely inside that window.
The Trap Works in Both Directions
Reports of this confusion keep accumulating. Cardiologists in Leicester, publishing in the same European journal under the title Not all that thickens is hypertrophic cardiomyopathy, described another 74-year-old woman whose MRI three days after admission showed swelling throughout the heart muscle, most intense at the apex, with the apex obliterating during systole in a pattern mimicking the genetic disease. The initial ballooning had already resolved, and there was no scarring on contrast imaging.
The reverse error is documented too. In the Journal of Cardiovascular Echography, cardiologists described a 66-year-old woman whose takotsubo presentation initially prevented anyone from suspecting a genuine apical hypertrophic cardiomyopathy, which became visible only once the stress cardiomyopathy had resolved.
The condition can also recur. A case followed over a decade in the European Heart Journal Cardiovascular Imaging documented apical thickening and swelling that resolved, then returned 9 years later with a second takotsubo episode, which resolved again.
Why the Distinction Is Not Academic
These two diagnoses lead to different lives. Apical hypertrophic cardiomyopathy is a genetic condition that brings lifelong cardiology follow-up, screening of first-degree relatives, discussion of arrhythmia risk, and, for some patients, an implantable defibrillator.
Takotsubo generally recovers. Getting the label wrong in one direction commits a patient and their family to unnecessary surveillance and worry. Getting it wrong in the other direction deprives someone who needs it of protection.
The tools that resolve it are tissue mapping on cardiac MRI and time. Mapping measures water content and distinguishes swelling from muscle. Serial imaging distinguishes swelling that resolves from thickening that does not. The Southampton team concluded that parametric mapping is crucial for distinguishing the two and avoiding the misdiagnosis of apical swelling as true thickening.
Persistent ECG changes should not settle the question on their own. The Southampton authors noted that published cohort data show takotsubo ECG changes typically resolve by 12 months, with a small minority persisting beyond that. Their patient was in the minority.
What This Means for Patients
These are individual case reports, so they cannot indicate how often mimicry occurs. Takotsubo itself is well recognized and generally carries a good outlook.
The useful takeaway is about pacing. A single scan after a cardiac event is a snapshot, and a snapshot of a swollen heart can mislead. In the Southampton case, the pumping fraction had already climbed from 45% to 59% by the time the first misleading MRI was taken. Patients told they may have a genetic heart muscle disease after an episode of stress cardiomyopathy have reasonable grounds to ask whether repeat imaging is planned and whether tissue mapping was performed.
Anyone with chest pain, breathlessness, or palpitations should seek prompt medical assessment. Questions about a cardiomyopathy diagnosis, family screening, or device therapy should be directed to a cardiologist who has the full imaging record.
Key Questions Answered
What is takotsubo syndrome? Often called broken heart syndrome, it is a stress-triggered condition in which part of the heart temporarily stops contracting normally, classically producing a ballooned apex. It usually resolves.
Why can it look like hypertrophic cardiomyopathy? Takotsubo causes the heart muscle to swell with fluid. The swollen muscle appears thickened on imaging, and during recovery, the ballooning resolves while the swelling persists.
How do doctors tell them apart? Tissue mapping on cardiac MRI measures water content, and swelling is not a feature of hypertrophic cardiomyopathy. Repeat imaging over weeks to months shows whether the thickening disappears.
Why does the distinction matter? Hypertrophic cardiomyopathy is genetic and involves lifelong follow-up, family screening, and possible defibrillator consideration. Takotsubo generally recovers.
How long can the ECG stay abnormal? Cohort data cited in the Southampton report indicate most takotsubo ECG changes resolve by 12 months. In their patient, abnormalities were still evident at two years.
Can the confusion go the other way? Yes. A published case describes genuine apical hypertrophic cardiomyopathy that was masked at presentation by takotsubo and became apparent only after the stress cardiomyopathy resolved.
