Characterization of priMary And sEcondary STress Related takOtsubo

Inclusion Criteria: For patients with TTS: * Informed consent signed by the patient or parent/guardian/legal representative. * TTS diagnosed based on modified Mayo Clinic Diagnostic Criteria as: (i) transient wall motion abnormality in the left ventricle beyond a single epicardial coronary artery distribution; (ii) absence of obstructive coronary artery disease or angiographic evidence of acute plaque rupture, which can explain the wall motion abnormality; (iii) new electrocardiographic abnormalities or elevation in cardiac troponin values; (iv) absence of pheochromocytoma or myocarditis. N.B. - All TTS diagnosis made according to Mayo Clinic Diagnostic Criteria will be a posterior compared to fulfil the new InterTAK Diagnostic Criteria (19). Myocarditis will be suspected based on clinical presentation (e.g. previous flu-like symptoms, increased inflammatory biomarkers) and confirmed by cardiac magnetic resonance.N.B. - Of note, primary TTS mainly concerns post-menopausal women with symptoms resulting from myocardial damage, emotional trigger, and evidence of normal coronary arteries at coronary angiography, whilst secondary TTS equally affects men and women, with physical triggers and in the presence of possible coronary artery disease at coronary angiography. For patients with sepsis: * Informed consent signed by the patient or parent/guardian/legal representative. * Diagnosis of sepsis, defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, which can be represented by an increase in the Sequential \[Sepsis-related\] Organ Failure Assessment (SOFA) score of 2 points or more. * Septic a shock, defined as vasopressor requirement to maintain a mean arterial pressure of 65 mmHg or greater and serum lactate level greater than 2 mmol/L (\>18 mg/dL) in the absence of hypovolemia. * Sepsis-induced cardiomyopathy, defined as left ventricular systolic dysfunction (LVSD) and/or LV diastolic dysfunction (LVDD) following sepsis in patients without known structural or functional cardiac disease. Exclusion Criteria: * Alternate diagnosis for the clinical presentation. * Contraindication to PET for patients with TTS (pregnancy, breast-feeding or patients considering becoming pregnant during the study period); * Patients with comorbidities having an expected survival \<1-year.