ABSTRACT
BACKGROUND: The incidence of systemic thromboembolism is high in patients with hypertrophic cardiomyopathy (HCM). The authors hypothesized that vulnerability to such vascular events could be caused by depressed left atrial appendage (LAA) function during normal sinus rhythm (SR). The aim of this cross-sectional study was to investigate LAA contractile function during SR in patients with HCM. METHODS: LAA function was assessed in 62 patients with HCM in SR and compared with that in 53 age-matched and sex-matched controls. Patients with histories of atrial fibrillation and documented episodes of paroxysmal atrial fibrillation on 24-hour Holter monitoring and depressed left ventricular ejection fractions (<50%) were excluded. Multiplane transesophageal echocardiography was performed for determination of the morphology and function of the LAA. RESULTS: LAA thrombi were present in five patients (8%) with HCM. LAA emptying and filling Doppler velocities were significantly depressed in the HCM group. LAA emptying and filling velocities were negatively correlated with age in controls (r = -0.4, P = .005), but these velocities were not associated with age in the HCM group. Moreover, LAA velocities were not associated with left ventricular mass index, left ventricular outflow tract gradient, or the degree of diastolic dysfunction in the HCM group. All Doppler tissue imaging velocities obtained from LAA walls were also significantly depressed in the HCM group. CONCLUSIONS: LAA thrombus formation was not rare in this patient population. The significantly depressed LAA filling and emptying velocities in SR may predispose patients with HCM to thromboembolic events. The depressed Doppler tissue imaging LAA parameters in patients with HCM may indicate the presence of a possible intrinsic atrial myopathy. Thromboembolic risk should be taken into account, and the evaluation of LAA morphology and function by transesophageal echocardiography might become a component of routine workup in patients with HCM in the future.
