trial fibrillation (AF) is a sustained arrhythmia that is most commonly found among persons in their 60 s, and its incidence is reported to be 2-4% of this generation. In people >75 years old, the incidence of AF has been reported to increase to 11.6%. [1][2][3] Thromboembolism is an important complication of AF that causes deterioration in the quality of life, 4,5 but the most appropriate candidates for anticoagulant therapy among patients with AF remain a matter of debate.Transesophageal echocardiography (TEE) is a useful clinical tool for identifying actual thrombi and for visualizing spontaneous echo contrast (SEC), a change which might predispose patients to develop atrial thrombosis. [6][7][8][9][10][11][12] The left atrial appendage (LAA) flow velocity measured by TEE has been used as a parameter of LAA function. 6,7,12,13 Several investigators have reported that AF patients with a low LAA blood flow velocity (reflecting impaired left atrial (LA) function) have a higher risk of thromboembolism than patients with an appendage flow >20 cm/s. 8,[12][13][14][15][16] In addition, the thrombin level is increased and platelet activation occurs in patients with either valvular or non-valvular AF. 17,18 Abnormal values of these markers might not appear however, until thrombin activation has commenced, and more importantly, such abnormal values might not necessarily reflect changes of cardiac origin.The level of brain natriuretic polypeptide (BNP) is increased in patients with various heart diseases, such as congestive heart failure, 19,20 dilated cardiomyopathy, 21 hypertrophic cardiomyopathy, hypertensive heart disease, 22 and lone AF. 23,24 Contrary to earlier theories that BNP is mainly secreted by the ventricular myocardium, 21,25,26 it was reported recently that the left atrium (not the left ventricle) is the main source of BNP in patients with AF. 23 The major findings of that study were : (1) patients with AF have significantly higher plasma BNP levels than control subjects; (2) a significant increase of BNP occurs between the coronary sinus (reflecting ventricular secretion) and the anterior interventricular vein (reflecting atrial secretion); and (3) there is a significant decrease of both plasma BNP and atrial BNP production after cardioversion of AF to sinus rhythm. 23,24 In the present study, we examined whether plasma BNP levels are higher in very elderly patients with clinical evidence of thromboembolism than in very elderly patients without this complication, and whether plasma BNP levels are correlated with LA function as represented by LAA flow.
Methods
PatientsWe studied 74 patients (38 men and 36 women aged, 75-96 years; mean, 82 years) with ECG-documented AF who were referred to our department for examination of cerebral vascular diseases. All patients underwent transthoracic and TEE, and then were classified into 2 groups.Circ J 2007; 71: 1446 -1451 (Received February 6, 2007 revised manuscript received May 22, 2007; accepted May 23, 2007 Background Assessment of left atrial (LA) function b...