Sustained hemoconcentration in patients with chronic atrial fibrillation, a potential risk for stroke and thromboembolic complications. A retrospective study.

Hemoconcentration has been observed during paroxysms of atrial fibrillation and at the early stage of chronic atrial fibrillation. The present study was designed to determine how long the hemoconcentration continues after complete transition to atrial fibrillation from sinus rhythm by retrospective long-term observation of 9 patients with chronic atrial fibrillation and 18 age-gender matched control patients. Hematocrit levels significantly increased with transition to chronic atrial fibrillation from sinus rhythm (from 44.88 +/- 0.87% to 46.87 +/- 1.12%, p < 0.01) and remained high for at least another 4 years. They remained unchanged throughout the observation period in the control patients. There is a significant difference in the hematocrit level between patients with chronic atrial fibrillation and control patients (p < 0.001). The hemoconcentration may present a potential risk for stroke and thromboembolic complications.