Cardiac Assessment and Takotsubo-stunning among COPD-exacerbations in-Hospital (CATCH study): when the lungs break your heart—protocol for a prospective observational cohort study

Introduction Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) may cause stress-induced transient acute cardiac dysfunction through myocardial stunning, in the form of exacerbation-triggered Takotsubo syndrome (referred to as Takotsubo stunning). Although prior studies suggest an association between AECOPD and transient cardiac dysfunction, existing evidence is limited to retrospective cohorts, case reports and expert consensus. Therefore, the incidence and clinical impact of Takotsubo stunning with acute heart failure (AHF) during AECOPD remain unknown and may be overlooked due to overlapping clinical symptoms. Cardiac Assessment and Takotsubo-stunning among COPD-exacerbations in-Hospital (CATCH study) aims to determine the incidence of Takotsubo stunning during AECOPD and to evaluate its clinical implication.Methods and analysis CATCH is a prospective observational cohort study enrolling adults (≥18 years) admitted for AECOPD at Sahlgrenska University Hospital (Gothenburg, Sweden). Participants with chronic left ventricular systolic dysfunction (left ventricular ejection fraction <50%), pre-existing chronic regional wall motion abnormalities (RWMA) or prior type 1 myocardial infarction are excluded. Following informed consent, participants undergo echocardiographic screening for RWMA and/or systolic left ventricular dysfunction. Screening-positive patients have follow-up echocardiography at 24 hours (±6) and 30 days (±48 hours). Those with reversible dysfunction constitute the CATCH case group, while screening-negative participants serve as controls. Additional assessments include ECG, chest X-ray, N-terminal pro-B-type natriuretic peptide blood analysis and COPD severity. Primary outcomes include the incidence of reversible RWMA or left ventricular dysfunction (proxy for Takotsubo stunning) and in-hospital clinical signs of AHF (Killip class >1). A sample size of 150 patients is required for detecting AHF differences (α=0.05, 80% power).Ethics and dissemination The study received ethical approval from the Swedish Ethical Review Authority. All participants provided written informed consent. Results will be disseminated through peer-reviewed journals and scientific meetings.Registration details The CATCH study is registered at ClinicalTrials.gov (NCT06597331). The reference number for ethical approval is 2024-02071-01 (with addenda 2024-05448-02 and 2025-05861-02).