Distinctive Hypertrophic Cardiomyopathy Anatomy and Obstructive Physiology in Patients Admitted with Takotsubo Syndrome

Abstract Clinical spectrum of hypertrophic cardiomyopathy (HC) has been expanded to include patients with mild or no thickening of the left ventricle (LV), who nevertheless have outflow tract obstruction at rest or after exercise, due to systolic anterior motion (SAM) and ventricular septal contact, with mitral valve elongation and papillary muscles anomalies. Apical ballooning mimicking a takotsubo syndrome (TS) wall motion pattern can occur in HC with mild septal thickening when latent obstruction becomes unrelenting. To define the prevalence of anatomic abnormalities characteristic of HC in patients diagnosed with TS we analyzed echocardiograms of 44 unselected TS patients, age 67±12 years, 95% women including studies performed before the event (n=11, median 515 days) and after recovery of left ventricular function (n=33, median 92 days, IQR=29-327) and compared the findings to 60 age and sexed matched controls. Analysis of echocardiograms was blinded to event timing, and patient vs. control status. During the ballooning event, 13 patients (30%) had SAM including 9 with LV outflow obstruction, peak gradients 71±40 mmHg, as well as: ventricular septal thickening (16±4mm), elongated anterior leaflets (AML) (30±3mm), and increased mitral coaptation to posterior wall distance (17±5 mm), consistent with diagnosis of the HC phenotype. Compared to 31 TS patients without SAM, study patients with SAM had longer AML (30±3 vs. 26±4 mm, p=0.006), thicker septum (16±4 vs. 12±3 mm), increased coaptation to posterior wall distance (17±5 vs.14±4 mm, p