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Regional left atrial stasis during atrial fibrillation and flutter: Determinants and relation to stroke
RISK
STRATIFICATION
stroke and to clinical and transthoracic echocardiographic variables. Results: The lowest velocity region was either the posterior left atrium or the appendage. Stroke frequency increased progressively and steeply with velocity < 15 cm/s in either region; this cutoff value had an 87% sensitivity and 40% specificity for stroke. Factors related to stasis were low left atrial ejection fraction, mitral regurgitation < 3 +, fibrillation (vs. type I flutter), left ventricular dilation and mitral valve area <2.0 cm 2. Conclusions: Posterior left atrial stasis appears to be as important as appendage stasis for the risk of stroke, which increases steeply with lower blood flow velocity in either region. Patients likely to have severe stasis during atrial arrhythmia are those with left ventricular dilation and low atrial ejection fraction accompanying left atrial dilation. Direct measurement of atrial velocity by transesophageal echocardiography appears to be useful for the identification of patients at risk for stroke during atrial arrhythmia.
collected data on 2231 patients who had left ventricular dysfunction after acute myocardial infarction who were enrolled in the Survival and Ventricular Enlargement trial. The mean follow-up was 42 months. Risk factors for stroke were assessed by both univariate and multivariate Cox proportional-hazards analysis. Results: Among these patients, 103 (4.6 percent) had fatal or nonfatal strokes during the study (rate of stroke per year of follow-up, 1.5 percent). The estimated five-year rate of stroke in all the patients was 8.1 percent. As compared with patients without stroke, patients with stroke were older (mean [-+SD] age, 63 -+ 9 years vs. 59 + 11 years; P < 0.001) and had lower ejection fractions (29 -+ 7 percent vs. 31 + 7 percent, P = 0.01). Independent risk factors for stroke included a lower ejection fraction (for every decrease of 5 percentage points in the ejection fraction there was an 18 percent increase in the risk of stroke), older age, and the absence of aspirin or anticoagulant therapy. Patients with ejection fractions of -<28 percent after myocardial infarction had a relative risk of stroke of 1.86, as compared with patients with ejection fractions of >35 percent (P = 0.01). The use of thrombolytic agents and captopril had no significant effect on the risk of stroke. Conclusions: During the five years after myocardial infarction, patients have a substantial risk of stroke. A decreased ejection fraction and older age are both independent predictors of an increased risk of stroke. Anticoagulant therapy appears to have a protective effect against stroke
Patent Foramen Ovale: Association Between the Degree of Shunt by Contrast Transesophageal Echocardiography and the Risk of Future Ischemic Neurologic Events D~ Stone,J. Godard,H.C.Con~tti,S.J.Kittner,C Sample,T.IL Price,G.D.Plotnick. Univenityof Ha~llandHospital,Baltimo~,HD. Am HeartJ 1996;131:158-61. This study investigated whether there is an association between the degree of interatrial shunting across a patent foramen ovale, as determined by saline contrast transesophageal echocardiography, and the risk of subsequent systemic embolic events, including stroke. Thirty-four patients found to have patent foramen ovale during transesophageal echocardiography were divided into two groups on the basis of the maximum number of microbubbles in the left heart in any single frame after intravenous saline contrast injection: group 1 (n = 16) with a "large" degree of shunt (->20 microbubbles) and group 2 (n = 18) with a "small" degree of shunt (->3 but <20 microbubbles). Patients were followed up over a mean period of 21 months for subsequent systemic embolic events, including transient ischemic attack and stroke. Five (31%) of the patients with large shunts had subsequent ischemic neurologic events, whereas none of the patients with small shunts had embolic events (p = 0.03). These events occurred in spite of antiplatelet or anticoagulant therapy. We conclude that patients with a large degree of shunt across a patent foramen ovale, as determined by contrast transesophageal echocardiography, are at a significantly higher risk for subsequent adverse neurologic events compared with patients with a small degree of shunt.
after myocardial infarction.
Regional Left Atrial Stasis During Atrial Fibrillation and Flutter: Determinants and Relation to Stroke B.ICShively,E~ Getgand,M.H.Crawford.CardiologySection501-1lIB, Albuque~lue VAMedicalCenter,Albuque~lue,NH. J Am CoilCa~liol1996;27:1722-9. Objectives: This study sought to 1) determine the location of left atrial stasis during atrial arrhythmia; 2) define the degree of stasis associated with significant risk of stroke; and 3) identify clinical or transthoracic echocardiographic data useful for predicting left atrial stasis. Background: Prior studies suggest that stroke during atrial arrhythmia is related to stasis in either the body of the left atrium or the appendage. Recent data indicate that appendage stasis is associated with appendage thrombus formation, but stroke during atrial arrhythmia occurs frequently in the absence of appendage stasis. Methods: Blood flow velocity was measured in multiple sites in the body of the left atrium and in the appendage by transesophageal pulsed wave Doppler echocardiography in 89 patients with atrial fibrillation or flutter. Regional velocities were related to the frequency of probable embolic
ACC CURRENTJOURNAL REVIEW May/June 1997
26
STRATIFICATION
stroke and to clinical and transthoracic echocardiographic variables. Results: The lowest velocity region was either the posterior left atrium or the appendage. Stroke frequency increased progressively and steeply with velocity < 15 cm/s in either region; this cutoff value had an 87% sensitivity and 40% specificity for stroke. Factors related to stasis were low left atrial ejection fraction, mitral regurgitation < 3 +, fibrillation (vs. type I flutter), left ventricular dilation and mitral valve area <2.0 cm 2. Conclusions: Posterior left atrial stasis appears to be as important as appendage stasis for the risk of stroke, which increases steeply with lower blood flow velocity in either region. Patients likely to have severe stasis during atrial arrhythmia are those with left ventricular dilation and low atrial ejection fraction accompanying left atrial dilation. Direct measurement of atrial velocity by transesophageal echocardiography appears to be useful for the identification of patients at risk for stroke during atrial arrhythmia.
collected data on 2231 patients who had left ventricular dysfunction after acute myocardial infarction who were enrolled in the Survival and Ventricular Enlargement trial. The mean follow-up was 42 months. Risk factors for stroke were assessed by both univariate and multivariate Cox proportional-hazards analysis. Results: Among these patients, 103 (4.6 percent) had fatal or nonfatal strokes during the study (rate of stroke per year of follow-up, 1.5 percent). The estimated five-year rate of stroke in all the patients was 8.1 percent. As compared with patients without stroke, patients with stroke were older (mean [-+SD] age, 63 -+ 9 years vs. 59 + 11 years; P < 0.001) and had lower ejection fractions (29 -+ 7 percent vs. 31 + 7 percent, P = 0.01). Independent risk factors for stroke included a lower ejection fraction (for every decrease of 5 percentage points in the ejection fraction there was an 18 percent increase in the risk of stroke), older age, and the absence of aspirin or anticoagulant therapy. Patients with ejection fractions of -<28 percent after myocardial infarction had a relative risk of stroke of 1.86, as compared with patients with ejection fractions of >35 percent (P = 0.01). The use of thrombolytic agents and captopril had no significant effect on the risk of stroke. Conclusions: During the five years after myocardial infarction, patients have a substantial risk of stroke. A decreased ejection fraction and older age are both independent predictors of an increased risk of stroke. Anticoagulant therapy appears to have a protective effect against stroke
Patent Foramen Ovale: Association Between the Degree of Shunt by Contrast Transesophageal Echocardiography and the Risk of Future Ischemic Neurologic Events D~ Stone,J. Godard,H.C.Con~tti,S.J.Kittner,C Sample,T.IL Price,G.D.Plotnick. Univenityof Ha~llandHospital,Baltimo~,HD. Am HeartJ 1996;131:158-61. This study investigated whether there is an association between the degree of interatrial shunting across a patent foramen ovale, as determined by saline contrast transesophageal echocardiography, and the risk of subsequent systemic embolic events, including stroke. Thirty-four patients found to have patent foramen ovale during transesophageal echocardiography were divided into two groups on the basis of the maximum number of microbubbles in the left heart in any single frame after intravenous saline contrast injection: group 1 (n = 16) with a "large" degree of shunt (->20 microbubbles) and group 2 (n = 18) with a "small" degree of shunt (->3 but <20 microbubbles). Patients were followed up over a mean period of 21 months for subsequent systemic embolic events, including transient ischemic attack and stroke. Five (31%) of the patients with large shunts had subsequent ischemic neurologic events, whereas none of the patients with small shunts had embolic events (p = 0.03). These events occurred in spite of antiplatelet or anticoagulant therapy. We conclude that patients with a large degree of shunt across a patent foramen ovale, as determined by contrast transesophageal echocardiography, are at a significantly higher risk for subsequent adverse neurologic events compared with patients with a small degree of shunt.
after myocardial infarction.
Regional Left Atrial Stasis During Atrial Fibrillation and Flutter: Determinants and Relation to Stroke B.ICShively,E~ Getgand,M.H.Crawford.CardiologySection501-1lIB, Albuque~lue VAMedicalCenter,Albuque~lue,NH. J Am CoilCa~liol1996;27:1722-9. Objectives: This study sought to 1) determine the location of left atrial stasis during atrial arrhythmia; 2) define the degree of stasis associated with significant risk of stroke; and 3) identify clinical or transthoracic echocardiographic data useful for predicting left atrial stasis. Background: Prior studies suggest that stroke during atrial arrhythmia is related to stasis in either the body of the left atrium or the appendage. Recent data indicate that appendage stasis is associated with appendage thrombus formation, but stroke during atrial arrhythmia occurs frequently in the absence of appendage stasis. Methods: Blood flow velocity was measured in multiple sites in the body of the left atrium and in the appendage by transesophageal pulsed wave Doppler echocardiography in 89 patients with atrial fibrillation or flutter. Regional velocities were related to the frequency of probable embolic
ACC CURRENTJOURNAL REVIEW May/June 1997
26