['Takotsubo cardiomyopathy is a syndrome of transient left ventricular dysfunction following acute emotional or physical stress without obstructive coronary artery disease. The leading hypothesis for the etiology is stress-induced catecholamine surge.', 'People taking outpatient β-adrenergic receptor antagonist therapy have less-severe presentation and clinical course of Takotsubo cardiomyopathy.', 'We identified patients diagnosed with Takotsubo cardiomyopathy from October 2005 to January 2011 by analyzing our cardiac-catheterization database. Clinical records and angiograms were reviewed by 2 experienced observers independently to confirm the diagnosis. We collected clinical, demographic, laboratory, and angiographic data for the identified patients. We then compared the severity of myocardial dysfunction or damage (cardiac enzymes, left ventricular end diastolic pressure, and left ventricular ejection fraction) between patients taking outpatient β-adrenergic antagonist therapy upon admission vs those who were not. Arrival and peak values for cardiac enzymes were analyzed when available. Analysis of parameters related to the severity of myocardial dysfunction or damage was conducted using the Mann-Whitney U test. Means for age were compared using the Student t test. Statistical significance was set at P < 0.05 (2-tailed).', 'Out of 64 patients identified, 16 (25%) were on one of 3 β-adrenergic antagonists on presentation: metoprolol succinate, metoprolol tartrate, or atenolol, with mean doses of 75 mg daily, 52.5 mg twice daily, and 37.5 mg daily, respectively. Patients on β-blockers were older (mean age 73.1 years vs 66 years; P < 0.05). There was no statistically significant difference in levels of cardiac enzymes, left ventricular end diastolic pressure, or left ventricular ejection fraction between the 2 groups.'] Does pretreatment with low-dose β-adrenergic antagonist therapy affect severity of Takotsubo cardiomyopathy?