Aims: Stress-induced cardiomyopathy (SIC) is an important differential diagnosis to acute myocardial infarction (AMI) that is associated with significant morbidity and mortality. The typical hallmark of SIC is left-ventricular apical akinesia but preserved function in basal segments. Catecholamines are postulated to play an important role in SIC but the precise pathophysiology is incompletely understood. Whether myocardial perfusion of the affected segments is impaired in SIC has been debated and remains unknown.
Methods and results: Myocardial contrast echocardiography (MCE) was used to study regional myocardial perfusion in a rat model of SIC. Twelve rats received 50 mg/kg isoproterenol (ISO) i.p. and were continuously monitored by MCE. Apical and basal perfusion were estimated and expressed as a ratio at baseline, 5, 10, 20, 30, 40, 50, 60, 70, 80, and 90 min post-ISO. The rats developed typical apical ballooning after 43 ± 9 min post-ISO injection. The ratio of apical:basal perfusion was close to 1.00 at all time-points and never dropped below 0.89 (95% CI never extended below 0.73). Light and electron microcoscopical investigation revealed no structural damage of myocardial vessels.
Conclusion: Apical perfusion is not impaired in the early phase of SIC in this rat model.
Keywords: Animal models of cardiovascular disease; Catecholamines; Echocardiography; Tako-tsubo syndrome.