Prevalence and severity of QT prolongation and other ECG abnormalities in takotsubo syndrome
Andrei D Margulescu1, Diluka Amila Premawardhana1, Dewi E Thomas1
1Department of Cardiology, Morriston Regional Cardiac Centre, Morriston Hospital, Heol Maes Eglwys, Swansea SA6 6NL, UK.
Insights
Long QT (LQT) is common in takotsubo syndrome (TS), often severe within 96 hours. Early ECGs may appear normal, necessitating prolonged monitoring for LQT in TS patients.
Area of Science:
- Cardiology
- Clinical Medicine
- Electrophysiology
Background:
- The prevalence and severity of QT interval prolongation (long QT, LQT) in takotsubo syndrome (TS) are not well described.
- Takotsubo syndrome, a form of non-ischemic cardiomyopathy, can present with ECG abnormalities.
- Understanding LQT in TS is crucial for patient management and risk stratification.
Purpose of the Study:
- To describe the prevalence and severity of QT interval prolongation (LQT) in patients with takotsubo syndrome (TS).
- To analyze the dynamic changes in ECG abnormalities, including LQT, T-wave inversion (TWI), ST segment elevation (STE), and ST segment depression (STD), in TS patients over time.
- To establish optimal monitoring duration for TS patients based on ECG findings.
Main Methods:
- Retrospective cohort study of patients with confirmed TS between January 2019 and December 2023.
- Manual measurement of corrected QT (QTc) interval using the Bazett formula in all available ECGs.
- Recording of other ECG abnormalities such as TWI, STE, and STD.
Main Results:
- Fifty-eight female patients (mean age 68 years) with TS were included.
- LQT was infrequent and mild within the first 3 hours but present in 90.9% of patients between 24-48 hours, severe in 63.6%.
- ECGs were normal in 40.5% within the first 6 hours; TWI prevalence increased significantly over time, and STE was common in the first 96 hours.
Conclusions:
- LQT is nearly universal in TS patients within 96 hours, often severe.
- ECG abnormalities in TS are dynamic, with frequent normal findings early on.
- Monitoring for at least 96 hours or until QTc falls below 500 ms is recommended for TS patients.
Background:
The prevalence and severity of QT interval prolongation (long QT, LQT) in takotsubo syndrome (TS) is not well described.
Methods:
This is a retrospective cohort study of all patients admitted in our Centre between January 2019 and December 2023 with confirmed TS. QT interval corrected for heart rate (QTc) (Bazzett formula) was measured manually in all available ECGs. Presence of other ECG abnormalities (T-wave inversion (TWI), ST segment elevation (STE), ST segment depression (STD)) were also recorded.
Results:
Fifty-eight patients were included, all women (68 ± 11 years). Fifty-six patients (96.6 %) had classical, apical ballooning form of TS. Symptoms included chest pain (93.1 %), dyspnoea (10.3 %), and others (5.2 %). Triggers were present in 70.7 % of patients. Three-hundred-and-thirty ECGs were analysed. LQT was infrequent in the first 3 h after symptom onset (23.5 % of patients), and was only mild. However, between 24 and 48 h after symptom onset, 90.9 % of patients developed LQT, which was severe (≥500 ms) in 63.6 % of patients. LQT prevalence decreased afterwards but QTc did not return to normal in 40.0 % of patients, and remained severely prolonged in 11.4 % of patients beyond 96 h. ECG was normal in 40.5 % of patients in the first 6 h. TWI was the predominant ECG change, and its prevalence increased from 16.7 % within the first 6 h to 76.9 % after 7 days. STE was present in 31.4 % of patients in the first 96 h, but was rare in isolation. Isolated STD did not occur.
Conclusion:
LQT is almost universally seen in patients with TS within the first 96 h after symptom onset, and is severe in the majority. ECGs abnormalities in TS are highly dynamic, but ECGs are frequently normal in the first 6 h after symptom onset. Patients should be monitored for at least 96 h after symptom onset, and until QTc falls below 500 ms.
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