The Beta-blockers in Takotsubo syndrome (TTS) (β-Tako) trial, is an academic, pragmatic, prospective, multicenter randomized clinical trial, aiming to assess the efficacy of beta-blockers (BB) in TTS patients. Two-hundred patients with TTS will be randomized (1:1) to BB (n=100) or no BB (n=100). BB with alpha or nitric oxide release activity will be used in the treatment arm. The primary endpoint will be the comparison of the wall motion score index by echocardiography at 7 days. A composite clinical endpoint (death, stroke, admission for recurrent TTS, ACS, heart failure or atrial fibrillation) at 1 year, will be assessed by an independent clinical events committee. Several sub-studies will be performed. The β-Tako trial will inform treatment decisions in this uniquely challenging clinical entity.

Takotsubo syndrome (TTS) is a cardiac condition mimicking acute coronary syndrome (ACS), characterized by transient left ventricular (LV) dysfunction in the presence of normal coronary arteries. Its etiology remains unknown but reversible microvascular dysfunction secondary to an adrenergic surge appears implicated. Treatment is empiric although in clinical practice most patients receive beta-blockers (BB). The Beta-blockers in TTS (β-Tako) trial, is an academic, pragmatic, prospective, multicenter randomized clinical trial, aiming to assess the efficacy of BB in TTS patients. TTS diagnosis will be confirmed by invasive coronary angiography and serial echocardiographic studies. Two-hundred patients with TTS will be randomized (1:1) to BB (n=100) or no BB (n=100). BB with alpha or nitric oxide release activity will be used in the treatment arm. The primary endpoint will be the comparison of the wall motion score index by echocardiography at 7 days, analyzed in an independent corelab. Changes in LV ejection fraction and global longitudinal strain will be also evaluated. A composite clinical endpoint (death, stroke, admission for recurrent TTS, ACS, heart failure or atrial fibrillation) at 1 year, will be assessed by an independent clinical events committee. Several sub-studies (clinical, imaging, biomarkers, pharmacogenetic, mRNAs, quality of life) will be performed. The β-Tako trial will generate valuable scientific evidence to address unmet clinical needs and inform clinical and treatment decisions in this uniquely challenging clinical entity.

Inclusion Criteria:

• Written informed consent.
• Diagnosis of TTS with exclusion of significant coronary artery disease (CAD) by invasive coronary angiography

Exclusion Criteria:

• Patients diagnosed of TTS > 48 hours before.
• Persistent ccardiogenic shock or severe hemodynamic instability
• Persistent severe (>30 mmHg) intraventricular gradient
• Previous diagnosis of severe valvular or ventricular disease or prior myocardial infarction secondary to atherosclerotic CAD
• Patients already receiving treatment with betablockers (*)
• Absolute contraindication/indication for beta-blockers (**)
• Poor echocardiographic window
• Pregnant or breastfeeding women.
• Participation in another clinical trial.

(*) Betablockers at a therapeutic dose at the time of symptom´s onset. (**) Close ECG monitoring required in patients with hypotension, bradycardia or cQT interval prolongation

Data will be considered to be shared by the PI and steering committee, upon adequate and justified request, within a defined scientific research project, and providing adequate supervision of the analysis and credit to the original inverstigators is prearranged

1 year after publication of the main combined clinical endpoint

to be defined

Outcome assessors blinded to treatment allocation Blinded independent clinical event committee PROBE initiative