1. A. Epidemiology update:
2. Stroke and AF
Embolic stroke
Content Points:
Stroke accounts for much of the morbidity and mortality associated with AF.

2. Stroke risk is increased in AF Content Points:
Framingham Heart Study investigators examined the impact of AF on stroke risk in 5184 male and female participants.1
Age-specific prevalence rates increased steadily from 1.8% for ages years to 10.2% for ages years.
In each age group, stroke rates were approximately 5-fold higher in groups with AF compared with groups without AF.
The percent of total stroke events attributed to AF (population attributable risk) increased from 7.3% in years age group to 30.8% in the years age group.
1Wolf PA, Abbott RD, Kannel WB. Atrial fibrillation: A major contributor to stroke in the elderly. Arch Intern Med. 1987;147:

3. Severity of stroke with AF Content Points:
Dulli et al reviewed the clinical presentations of patients with acute ischemic stroke admitted between 1990 and
Of 1061 patients with acute ischemic stroke, 216 (20.3%) had AF. The frequency of bedridden state was 41.2% in patients with AF compared with 23.7% in patients without AF (P < ).
The odds ratio for bedridden state following ischemic stroke due to AF was 2.23 (95% confidence interval [CI], ; P < ) by multivariate logistic regression.
The investigators concluded that ischemic stroke associated with AF is typically more severe than ischemic stroke due to other etiologies, and this increased severity is independent of advanced age and other stroke risk factors.
1Dulli DA, Stanko H, Levine RL. Atrial fibrillation is associated with severe acute ischemic stroke. Neuroepidemiology. 2003;22:

4. Framingham risk score: Relation to 5-year stroke risk Content Points:
Using Framingham Heart Study data, Wang et al developed a model for calculating the risk of stroke in patients with a first-detected episode of AF.1
The risk score for stroke is based on age, gender, systolic blood pressure, diabetes, and prior stroke or transient ischemic attack (TIA). Points are assigned according to the presence/absence (ie, diabetes) or level (ie, age in year, or blood pressure in mm Hg). These points are added up and the total score is correlated with 5-year risk of stroke in a table provided by the investigators.
The slide shows the relation of risk score to stroke risk.
1Wang TJ, Massaro JM, Levy D, Vasan RS, Wolf PA, D'Agostino RB, et al. A risk score for predicting stroke or death in individuals with new-onset atrial fibrillation in the community: The Framingham Heart Study. JAMA. 2003;290:

5. Framingham risk score: Relation to 5-year risk of stroke/death
Content Points:
In the Framingham model, risk of stroke or death is based on a somewhat different set of factors than for stroke alone. This score is based on age, systolic blood pressure, diabetes, smoking, prior myocardial infarction (MI) or heart failure, heart murmur, and electrocardiographic left ventricular hypertrophy (ECG LVH).1
The 5-year risk of stroke or death is calculated by adding the scores for each of these factors.
1Wang TJ, Massaro JM, Levy D, Vasan RS, Wolf PA, D’Agostino RB, et al. A risk score for predicting stroke or death in individuals with new-onset atrial fibrillation in the community: The Framingham Heart Study. JAMA. 2003;290:

6. Impact of selected AF risk factors on predicted 5-year risk of stroke/death
Content Points:
The slide demonstrates that 5-year risk calculated from the Framingham model rises sharply in the presence of >2 risk factors.1
1Wang TJ, Massaro JM, Levy D, Vasan RS, Wolf PA, D’Agostino RB, et al. A risk score for predicting stroke or death in individuals with new-onset atrial fibrillation in the community: The Framingham Heart Study. JAMA. 2003;290:

7. LV systolic dysfunction on echocardiography predicts stroke in AF patients
Content Points:
In addition to clinical predictors of risk, echocardiography can contribute to risk stratification. The Atrial Fibrillation Investigators analyzed transthoracic echocardiographic data from three randomized clinical trials (Boston Area Anticoagulation Trial for Atrial Fibrillation, Stroke Prevention in Atrial Fibrillation 1 Study, and Veterans Affairs Prevention in Atrial Fibrillation Study) and correlated these data to subsequent ischemic stroke.1
As shown, the stroke rate increased with increasing degree of left ventricular (LV) dysfunction.
The investigators showed that moderate to severe LV dysfunction predicted stroke risk independent of hypertension, age, previous stroke/TIA, diabetes, and heart failure (relative risk 2.5; 95% CI, ; P < 0.001).
1Atrial Fibrillation Investigators, Atrial Fibrillation, Aspirin, Anticoagulation Study, European Atrial Fibrillation Study, Stroke Prevention in Atrial Fibrillation Study, Boston Area Anticoagulation Trial for Atrial Fibrillation Study, Canadian Atrial Fibrillation Study, Veterans Affairs Prevention in Atrial Fibrillation Study. Echocardiographic predictors of stroke in patients with atrial fibrillation: A prospective study of 1066 patients from 3 clinical trials. Arch Intern Med. 1998;158:

8. SPAF III: Stroke/systemic embolism event rates according to TEE findings
Content Points:
Transesophageal echocardiography (TEE) offers several advantages over transthoracic echocardiography (TTE) for clot visualization. It provides a clearer view of the left atrial appendage, permits measurement of left atrial appendicular flow and outflow blood velocity, enhances clot identification, and possibly improves stroke risk estimate.1
Investigators from the SPAF III trial analyzed TEE data from 42 patients to determine the correlation between specific TEE findings and embolic risk.2
As illustrated on the slide, TEE findings suggestive of left atrial abnormality or complex aortic plaque identified high-risk patients.
There was a 7.8% rate of stroke or systemic emboli in patients with left atrial abnormality (thrombus, dense spontaneous echocardiographic contrast, or peak antegrade velocity of blood flow <20 cm/s).
There was a 12% event rate in patients with complex aortic plaque.
There was a 20.5% event rate in patients with both left atrial abnormality and complex plaque.
Conversely, there was a much lower event rate (1.3%) in patients with neither left atrial abnormality or complex plaque.
1Manning WJ, Weintraub RM, Waksmonski CA, Haering JM, Rooney PS, Maslow AD, et al. Accuracy of transesophageal echocardiography for identifying left atrial thrombi: A prospective, intraoperative study. Ann Intern Med. 1995;123: SPAF Investigators Committee on Echocardiography. Transesophageal echocardiographic correlates of thrombo embolism in high-risk patients with nonvalvular atrial fibrillation. Ann Intern Med. 1998;128: