Embolism and atrial fibrillation. A longitudinal follow-up
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T Yipintsoi1, W Jirathamopas, C Suntiparpluacha
1Department of Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand.
Insights
Patients with chronic atrial fibrillation (AF) and specific underlying conditions have varying risks of systemic embolism. Identifying low-risk AF patients may help avoid unnecessary anticoagulation therapy.
Area of Science:
- Cardiology
- Vascular Medicine
- Clinical Epidemiology
Background:
- Chronic atrial fibrillation (AF) is a significant risk factor for systemic embolism.
- Anticoagulation is a standard treatment to prevent embolic events in AF patients.
- The risk of embolism in AF varies based on underlying etiological factors.
Purpose of the Study:
- To assess the incidence of systemic embolism in patients with chronic atrial fibrillation across different etiological disease groups.
- To determine if specific disease groups have a significantly higher or lower risk of embolic events.
- To inform clinical decision-making regarding the necessity of anticoagulation in various AF patient subgroups.
Main Methods:
- A cohort of 649 patients with proven chronic atrial fibrillation was followed for 1,436 patient-years.
- Patients were stratified into 7 distinct disease groups based on their primary cardiac condition.
- Systemic embolism events were recorded and analyzed within each disease group.
Main Results:
- The highest rates of systemic embolism (3.9-5.1 per 100 patient-years) were observed in patients with rheumatic valvular disease (primarily mitral stenosis) and ischemic heart disease.
- Lower embolic rates (0-0.9 per 100 patient-years) were found in patients with heart failure, non-rheumatic mitral regurgitation, atrial septal defect, and thyrotoxicosis.
- Pre-existing embolic events correlated with higher embolic rates during the follow-up period.
Conclusions:
- The incidence of systemic embolism in chronic atrial fibrillation is disease-specific.
- Patients in low-risk etiological groups may not derive substantial benefit from anticoagulation therapy.
- Further research is needed to accurately define the true low-risk patient populations for atrial fibrillation.
Abstract:
Six hundred and forty-nine patients with proven chronic atrial fibrillation were followed for a total of 1,436 patient-years without anticoagulation. The patient were divided into 7 disease groups with each having an average age ranging from 39 to 69 years. Eleven per cent of the patients had systemic embolism prior to being registered for the follow-up. The diseases which had the highest incidence of embolism prior to being followed were the same as those producing the highest rate of systemic embolism while under observation. The disease groups were rheumatic valvular (predominantly mitral stenosis) and ischemic heart diseases. Their embolic rate were 3.9 to 5.1 emboli per 100 pt-yr. Other disease groups with lower embolic rates of 0 to 0.9 per 100 pt-yr were heart failure, non-rheumatic mitral regurgitation, atrial septal defect and thyrotoxicosis. Since the incidence of systemic embolism varied according to the primary disease, and since the hemorrhagic complication of anticoagulant therapy is finite, it is advised that low risk group may not benefit greatly from anticoagulation. However, the true low risk group has still to be properly determined.