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Increased intracardiovascular clotting in patients with chronic atrial fibrillation
K Kumagai1, M Fukunami, M Ohmori
1Division of Cardiology, Osaka Prefectural Hospital, Japan.
Insights
Atrial fibrillation itself, not predisposing factors like mitral stenosis, significantly increases plasma D-dimer levels, indicating a higher risk of thrombus formation. This suggests atrial fibrillation plays a key role in developing intracardiovascular clotting.
Area of Science:
- Cardiology
- Hematology
- Thrombosis Research
Background:
- Atrial fibrillation is associated with an increased risk of thromboembolism.
- Predisposing factors like mitral stenosis may also contribute to thrombus formation.
Purpose of the Study:
- To investigate whether atrial fibrillation itself or predisposing conditions are primary drivers of thrombus formation.
- To differentiate the contribution of atrial fibrillation versus underlying heart disease to clotting.
- To assess plasma D-dimer levels as a marker for intracardiovascular clotting in these patient groups.
Main Methods:
- Plasma D-dimer levels were measured in patients with (Group 1) and without (Group 2) atrial fibrillation.
- Group 1 included patients with lone atrial fibrillation and those with predisposing factors (e.g., valvular heart disease).
- Group 2 included patients without atrial fibrillation but with organic heart disease or chest pain syndrome.
Main Results:
- Significantly higher plasma D-dimer levels were observed in patients with atrial fibrillation (Group 1) compared to those without (Group 2) (150 +/- 19 ng/ml vs. 61 +/- 3 ng/ml, p < 0.01).
- No significant difference in D-dimer levels was found between patients with and without organic heart disease within either group.
- These results highlight the elevated clotting activity directly associated with atrial fibrillation.
Conclusions:
- Atrial fibrillation itself appears to be a more significant factor in the development of intracardiovascular clotting than predisposing conditions.
- Elevated D-dimer levels in atrial fibrillation patients suggest an increased propensity for thrombus formation.
- Findings support the direct pro-thrombotic effect of atrial fibrillation, independent of underlying valvular disease.
Abstract:
To clarify whether the formation of thrombi could be induced by atrial fibrillation itself or by factors predisposing to atrial fibrillation such as mitral stenosis, plasma D-dimer levels (cross-linked fibrin degradation products) were measured in 73 patients without atrial fibrillation (Group 2). In Group 1, 49 of the 73 patients had factors predisposing to atrial fibrillation such as valvular heart disease, and the remaining 24 had lone atrial fibrillation. In Group 2, 16 patients had organic heart disease and the remaining 5 had a chest pain syndrome. The plasma D-dimer level was significantly higher in Group 1 (150 +/- 19 ng/ml) than in Group 2 (61 +/- 3 ng/ml) (p less than 0.01, mean +/- standard error of the mean). In both groups, there were no significant differences in plasma D-dimer level between patients with and without organic heart disease (146 +/- 18 versus 156 +/- 46 ng/ml in Group 1; 61 +/- 4 versus 59 +/- 10 ng/ml in Group 2). These findings indicate that atrial fibrillation itself may be more important than factors predisposing to atrial fibrillation in the development of intracardiovascular clotting.