Plasma catecholamine levels in the acute and subacute stages of takotsubo syndrome: Results from the Stockholm myocardial infarction with normal coronaries 2 study.

AIMS: It is well-accepted that takotsubo syndrome (TS) is characterized by a massive surge of plasma catecholamines despite lack of solid evidence. The objective of this study was to examine the hypothesis of a massive catecholamine elevation in TS by studying plasma-free catecholamine metabolites in patients participating in the Stockholm myocardial infarction (MI) with normal coronaries 2 (SMINC-2) study where TS constituted more than one third of the patients. METHODS AND RESULTS: The patients included in the SMINC-2 study were classified, according to cardiac magnetic resonance (CMR) imaging findings (148 patients), which was performed at a median of 3 days after hospital admission. Plasma-free catecholamine metabolites; metanephrine, normetanephrine, and methoxy-tyramine were measured on day 2-4 after admission. Catecholamine metabolite levels were available in 125 patients. One hundred and ten (88%) of the 125 patients included in SMINC-2 study, and 38 (86.4%) of the 44 patients with TS had completely normal plasma metanephrine and normetanephrine levels. All patients had normal plasma methoxy-tyramine levels. Fourteen (11.2%) of the 125 patients included in SMINC-2 study, and 5 (11.6%) of the 43 patients with TS had mild elevations (approximately 1.2 times the upper normal limits) of either plasma metanephrine or normetanephrine. One patient with pheochromocytoma-triggered TS had marked elevation of plasma metanephrine and mild elevation of plasma normetanephrine. There were no significant differences between the number or degree of catecholamine metabolite elevations between the different groups of patients with CMR imaging diagnosis included in SMINC-2 study. CONCLUSION: There was no evidence of massive catecholamine elevations in the acute and subacute stages of TS apart from one patient with pheochromocytoma-induced TS. Most of the TS patients had normal catecholamine metabolites indicating that blood-borne catecholamines do not play a direct role in the pathogenesis of TS.

ST-segment elevation and cardiac magnetic resonance imaging findings in myocardial infarction with non-obstructive coronary arteries.

PURPOSE: Patients with myocardial infarction and non-obstructive coronary arteries (MINOCA) may present with or without ST-elevation (STE) on the electrocardiogram (ECG). Previous studies have shown that STE was associated with higher risk of early mortality and long-term major adverse coronary events, and that cardiac magnetic resonance imaging (CMR) can help to determine whether the cause of a MINOCA presentation is ischemic or non-ischemic. We set out to determine the relationship between STE and CMR findings in patients presenting with MINOCA. DESIGN: Patients who underwent CMR based on a provisional diagnosis of MINOCA were pooled from three prospective cohort studies: the multicenter Stockholm Myocardial Infarction with Normal Coronaries, a prospective University of Adelaide study, and a prospective NYU School of Medicine diagnostic imaging study. STE was defined as ≥1 mm in ≥2 contiguous leads. RESULTS: Among 292 patients, average age was 57.0 years (±11.9), and 68% were female. Fifty-seven had STE, 231 had no STE and four had left bundle branch block. There was no difference between patients with vs. without STE in the likelihood of the CMR findings of infarction (21% vs. 18%), myocarditis (10% vs. 14%), left ventricular wall motion pattern consistent with takotsubo syndrome on CMR (16% vs. 14%). CONCLUSION: STE on the presenting ECG was not associated with CMR findings in patients with a provisional diagnosis of MINOCA. Based on these findings, increased risk among MINOCA patients with STE does not appear to be related to variation in these CMR findings.