Cognitive disorders in elderly patients with permanent atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a risk factor for development of thromboembolic events with an annual stroke rate of 4.5%. In subjects over 80 years AF is the single leading cause of major stroke. Moreover, about 25% of patients with AF in the absence of neurological deficits have tomographic signs of one or more silent cerebral infarcts.

AIM: To investigate whether cognitive function in patients with permanent AF is significantly worse than in patients with sinus rhythm.

METHODS: We included subjects aged > 65 years, without previous cerebrovascular events or dementia, with permanent arrhythmia lasting > 12 months. The AF group comprised 51 patients, aged 75.8 years. The control group consisted of 43 patients with sinus rhythm. The main points of the study protocol were: clinical history recording, physical examination, biochemical analyses, standard 12-lead ECG and transthoracic echocardiography. Cognitive status was assessed by Mini Mental State Examination (MMSE).

RESULTS: Patients had established AF with a median duration of 4.9 years (range 1-21 years). Of the 51 patients, 51% had hypertension, 37% coronary artery disease, 12% presented sick sinus syndrome or atrioventricular advanced block with a VVI pacemaker implanted. There were no significant differences between the two groups though AF patients presented left ventricular hypertrophy and history of myocardial infarction more frequently. Patients in the sinus group had a lower-risk profile and received antithrombotic therapy less frequently than the AF group. However, a significant proportion of patients, particularly in the AF group received less than optimal thromboembolic prophylactic treatment with anticoagulants. Cognitive status was found to be significantly lower in the AF group, compared with the sinus rhythm group: 24.8 +/- 3.1 vs. 27.1 +/- 2.6 (p < 0.05). There were 43% patients with cognitive impairment in the AF group and 14% in the sinus rhythm group.

CONCLUSIONS: Permanent AF in patients aged over 65 years seems to be associated with lower MMSE score compared with subjects with sinus rhythm. Cognitive impairment in older patients is a multifactorial disorder. One of the causes of low cognitive function in these patients appears to be permanent AF. Further prospective clinical trials should help determine the possible role of inadequate anticoagulant treatment, and its association with the deterioration of cognitive function in AF patients.