Regadenoson Cardiac Stress Test-Induced Takotsubo Cardiomyopathy: A Case Report

A 79-year-old female presented with acute left-sided chest pain with shortness of breath; she was afebrile and vitally stable. She had a mildly elevated troponin (0.11 ng/mL). Her N terminal pro B-type natriuretic peptide (NT-proBNP) was 7053 pg/mL and electrocardiography (ECG) showed nonspecific ST, T wave changes. Transthoracic echocardiogram (TTE) revealed an ejection fraction (EF) of 65-70%. She was diagnosed with a non-ST elevation myocardial infarction (NSTEMI) and underwent a nuclear stress test, which was negative for ischemia with no left ventricular motion abnormality and an EF of 73%. The patient developed acute respiratory failure following the Lexiscan (Astellas Pharma US, Northbrook, IL) and had to be intubated. A chest X-ray showed pulmonary edema, and transesophageal echocardiography (TEE) revealed a severely reduced EF of 25% with a new anterior wall motion abnormality. Left heart catheterization showed no significant coronary artery disease. Ventriculogram revealed a significantly reduced EF of 30% with apical akinesia. These findings were compatible with myocardial infarction with non-obstructive coronary arteries (MINOCA), likely secondary to regadenoson, which presented like takotsubo cardiomyopathy (TCM). Her condition gradually improved and the follow-up echo revealed baseline EF without symptoms of heart failure. In conclusion, takotsubo cardiomyopathy can be a potential complication from Lexiscan and can present as new-onset heart failure after the stress test.