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Relations between left atrial appendage blood flow velocity, spontaneous echocardiographic contrast and thromboembolic risk in vivo.

OBJECTIVES: The aim of this study was to determine the relations between spontaneous echo contrast, left atrial appendage blood flow velocity and thromboembolism. BACKGROUND: Left atrial thrombus and spontaneous echo contrast, a putative marker of thromboembolic risk, are frequently located in the left atrial appendage. Measurement of left atrial appendage outflow Doppler velocity by transesophageal echocardiography is a recent technique for assessment of left atrial appendage function, which may be important in thrombus formation. METHODS: Transthoracic and transesophageal echocardiographic studies were performed in 140 patients with atrial fibrillation (chronic in 80 patients, paroxysmal in 50 patients, first episode < 2 weeks in 10 patients). The left atrium and appendage were inspected for thrombus and spontaneous echo contrast, which was graded from 0 (none) to 4+ (severe). Outflow velocity profiles were obtained by pulsed wave Doppler at the orifice of the left atrial appendage. RESULTS: Left atrial spontaneous echo contrast was present in 78 patients (56%). In multivariate logistic regression analysis, spontaneous echo contrast was the only significant correlate of left atrial thrombus and was present in 14 (93%) of 15 patients. Spontaneous echo contrast and age were associated positively, and anticoagulant therapy was associated negatively, with previous thromboembolic events. Increasing grades of spontaneous echo contrast were associated with decreasing left atrial appendage blood velocity. The velocity in patients with thrombus was not significantly different from that in patients with 4+ spontaneous echo contrast. In multivariate linear regression analysis, the grade of spontaneous echo contrast was significantly and negatively associated with left atrial appendage velocity (p = -0.0001) and mitral regurgitation (p = -0.0002) and significantly and positively associated with left atrial area (p = 0.0005). The odds ratio for spontaneous echo contrast was 28:1 for low left atrial appendage blood flow velocity (< 35 cm/s) and 96:1 for low velocity and the absence of mitral regurgitation. CONCLUSIONS: Spontaneous echo contrast is the cardiac factor most strongly associated with left atrial appendage thrombus and embolic events. Spontaneous echo contrast formation is promoted by reduced blood flow velocity and increased left atrial size but is diminished by mitral regurgitation.

Adult↗

Influence of aging on left atrial appendage flow velocity patterns in normal subjects.

Transesophageal pulsed Doppler echocardiography was performed to examine changes with age in the left atrial appendage flow velocity patterns in 50 normal subjects (15 to 80 years) in sinus rhythm. There was a significant negative correlation between the peak early diastolic forward and backward left atrial appendage flow velocities and age, as well as a significant positive correlation between the peak early diastolic forward left atrial appendage flow velocity and the peak early diastolic transmitral and pulmonary venous flow velocities. Although there was a significant positive correlation between the peak atrial systolic transmitral flow velocity and age, there was a negative correlation between the peak atrial systolic forward and backward left atrial appendage flow velocities and age. There was a positive correlation between both the maximum left atrial diameter and the amplitude of the interatrial septal motion during atrial systole and age. There was a significant negative correlation between the left atrial appendage ejection fraction during atrial systole and age. Left atrial appendage thrombi and spontaneous echo contrast were detected in two subjects with low peak early diastolic and atrial systolic left atrial appendage flow velocities. In conclusion, both peak early diastolic and atrial systolic left atrial appendage flow velocities decreased with age. A decrease in the peak atrial systolic flow velocity appeared to be an important sign of left atrial appendage thrombus formation even in normal elderly subjects in sinus rhythm.

Adolescent↗

Influence of left atrial pressure on left atrial appendage flow velocity patterns in patients in sinus rhythm.

To examine changes in left atrial appendage flow velocity patterns in relation to left atrial pressures during sinus rhythm, transesophageal echocardiography and cardiac catheterization were performed in 31 patients with myocardial diseases in sinus rhythm and 20 control subjects without cardiovascular disease. The 31 patients were divided into two groups according to mean pulmonary capillary wedge pressure: the group with high wedge pressure (19.9 +/- 5.8 mmHg) and the group with low wedge pressure (8.6 +/- 2.9 mmHg). The left atrial appendage peak early emptying velocity was decreased significantly in the groups with both high and low wedge pressure compared with the control group. The left atrial appendage peak late emptying velocity was significantly greater in the group with low wedge pressure compared with the control group, whereas it was decreased significantly in the group, with high wedge pressure compared with the control group. The left atrial appendage peak late emptying velocity had a significant negative correlation with wedge pressure. The maximum left atrial appendage area at end systole in the group with high wedge pressure was significantly greater than that in both the group with low wedge pressure and the control group. There was a significant positive correlation between the maximum left atrial appendage area and the wedge pressure, as well as a significant negative correlation between the left atrial appendage ejection fraction during atrial contraction and the wedge pressure. In the group with high wedge pressure, one patient had evidence of left atrial appendage thrombi and two had spontaneous echo contrast. These results suggest that even in patients in sinus rhythm, a marked elevation in the left atrial pressure is likely to reduce the left atrial appendage peak early and late emptying velocities. These changes may be accompanied by an increased incidence of thrombus formation in the left atrial appendage compared with individuals with normal or only slightly elevated left atrial pressures.

Atrial Function↗

Hemodynamic abnormalities in the left atrial appendage in patients with paroxysmal atrial fibrillation, with special reference to albumin-contrast echocardiographic aspects.

AIM: We assessed the prolonged dysfunction of the left atrial appendage caused by paroxysmal atrial fibrillation. METHODS AND RESULTS: Transesophageal echocardiography with intravenous albumin-microspheres (Albunex, 0.2 ml/kg) was performed in 100 consecutive patients (44 patients in sinus rhythm without previous paroxysmal atrial fibrillation: 13 patients in sinus rhythm who had had previous episodes of paroxysmal atrial fibrillation; and 43 patients with sustained atrial fibrillation). We compared the left atrial appendage ejection fraction and degree of opacification in the left atrial appendage with Albunex in the groups. Patients with previous paroxysmal atrial fibrillation had lower left atrial appendage ejection fractions than patients in sinus rhythm without paroxysmal atrial fibrillation (33 +/- 14 vs. 47 +/- 14%, p < 0.001). More than half of the patients (7/13 [54%]) with previous paroxysmal atrial fibrillation showed delayed and incomplete opacification of the left atrial appendage with Albunex. CONCLUSION: We conclude that paroxysmal atrial fibrillation causes left atrial appendage stunning, at least in some patients.

Aged↗

Inversion of the left atrial appendage following cardiac surgery.

Inversion of the left atrial appendage is a rare complication after open-heart surgery. To our knowledge only 16 cases, besides that reported herein, have been described so far. Echocardiographically, the inverted left atrial appendage appears as a mass mimicking a thrombus, a vegetation or a tumor of the left atrium. Lack of awareness of this entity can result in a misdiagnosis and unnecessary procedures. The case here reported deals with an inverted left atrial appendage occurring in an infant after repair of an atrial septal defect.

Atrial Appendage↗

A case of inverted left atrial appendage mimicking a tumor.

We report a rare case of an inverted left atrial appendage without prior cardiac surgery. A left atrial mass was incidentally found during routine echocardiography in a 19-year-old man with mitral valve prolapse. Echocardiography revealed a hyperechoic mass in the left atrium, and a neoplastic lesion could not be excluded. On magnetic resonance imaging (MRI), this mass consisted of fat tissue that showed continuation to epicardial fat, indicating an inverted left atrial appendage mimicking a tumor in the left atrium. When a mass in the left atrium is observed on echocardiography, there are several differential diagnoses, including thrombus, vegetation, and intra-atrial neoplasms such as myxomas. Recently, several studies reported cases with inverted left atrial appendages mimicking tumors in patients after cardiac operations. We present a case of inverted left atrial appendage without any prior cardiac surgery. Cardiac MRI was highly useful to obtain the final diagnosis of inverted left atrial appendage.

Adipose Tissue↗

Transesophageal two-dimensional echocardiography for the detection of left atrial appendage thrombus.

Thrombi located in the left atrial appendage are frequently not detected with conventional two-dimensional echocardiography. The transesophageal echocardiographic approach readily visualizes left atrial morphology and may be used as an alternative. In 6 of 21 patients with mitral valve stenosis, a left atrial appendage thrombus was diagnosed by transesophageal two-dimensional echocardiography when transthoracic echocardiography had failed. The transesophageal echocardiographic findings were confirmed at surgery for mitral valve replacement in all cases.

Adult↗

Transcatheter occlusion of the left atrial appendage for stroke prevention.

Patients with atrial fibrillation are at an increased risk of having a cardioembolic stroke. Most of the thrombi responsible for these ischemic events originate in the left atrial appendage. Percutaneous occlusion of the left atrial appendage is a new approach to stroke prevention in patients with atrial fibrillation and contraindication for long-term warfarin treatment. Three different devices have been used so far: the PLAATO system, the WATCHMAN filter system and the Amplatzer septal occluder. Left atrial appendage occlusion using these devices is feasible and safe and has shown promising results. The risk of stroke in atrial fibrillation patients appears to be reduced.

Atrial Appendage↗

Massive left atrial appendage aneurysm presenting as supraventricular tachycardia.

Left atrial appendage aneurysm is a rarely reported condition. Symptoms are absent in childhood and diagnosis is usually incidental. Systemic embolization or arrhythmia can bring these cases to medical attention. We report the case of a 12-year-old male with massive left atrial appendage aneurysm who presented with effort intolerance and supraventricular arrhythmia. The diagnosis was made by transthoracic echocardiography. Magnetic resonance imaging and left atriogram were also done before surgical resection.

Aneurysm↗

Congenital intrapericardial aneurysm of the left atrial appendage.

Congenital aneurysmal dilatation of the left atrial appendage is a rare but correctable lesion. It represents a diagnostic dilemma in patients with cardiomegaly and is commonly associated with supraventricular arrhythmias and life-threatening systemic embolization. We describe the diagnostic evaluation and surgical treatment during 1997 of a patient with congenital aneurysmal dilatation of the left atrial appendage. The patient was discharged previously from our hospital in 1967 with the diagnosis of congenital dilatation of the pulmonary artery.

Child↗

[Functional assessment of the left atrial appendage with transesophageal echocardiography before and after percutaneous valvotomy in the mitral stenosis].

OBJECTIVE: To assess the effects of the relief of the mitral stenosis by percutaneous ballon valvotomy in the function of the left atrial appendage. METHODS: Twelve patients with symptomatic mitral stenosis, in sinus rhythm, were studied. They were submitted to the transesophageal echocardiogram before and after effective percutaneous ballon valvotomy. Concerning the left atrial appendage, the peak flow velocities and the respective integral of the anterograde and retrograde flow, in addition to the ejection fraction calculated through the planimetry of the area of that structure, were analyzed at the pulsatile Doppler. RESULTS: There was a significant increase of the anterograde flow velocity of the left atrial appendage after percutaneous ballon valvotomy (pre: mean of 0.30 m/s; post: mean of 0.47 m/s; p<0.05) and their respective integrals. The same happened with the retrograde flow velocity (pre: mean of 0.35 m/s, post: mean of 0.53 m/s; p<0.05). There was a tendency of increase of the ejection fraction of the left atrial appendage after the procedure (pre: mean of 20%, post: mean of 31%; p=0.08). CONCLUSION: The effective opening of the stenosed mitral orifice resulting from the percutaneous ballon valvotomy determined an improvement of the flow pattern of the left atrial appendage, which can potentially contribute for the reduction of the embolic risk.

Adolescent↗

Assessment of left atrial appendage function by biplane transesophageal echocardiography in patients with nonrheumatic atrial fibrillation: identification of a subgroup of patients at increased embolic risk.

OBJECTIVES: This study was conducted to identify a subgroup of patients with nonrheumatic atrial fibrillation with an increased risk for cardiogenic embolism by assessing left atrial appendage function. BACKGROUND: Patients with nonrheumatic atrial fibrillation have an increased risk for thromboembolic complications. The left atrial appendage is the most likely source for thrombus formation. It is likely that the appendage function (contraction, filling dynamics) is related to the pathogenesis of thrombus formation. METHODS: Twenty-nine patients with nonrheumatic atrial fibrillation (group I) underwent biplane transesophageal echocardiography. The maximal and minimal areas during a cardiac cycle and the peak emptying and filling velocities of the appendage were measured in both scan planes. For comparison, two additional groups were also analyzed. Group II consisted of 12 patients with chronic atrial fibrillation due to significant mitral stenosis, and group III consisted of 30 patients who were in sinus rhythm. RESULTS: Patients with nonrheumatic atrial fibrillation showed two distinct appendage flow patterns: either well defined peak filling and emptying waves (> or = 25 cm/s) with visible fibrillatory contractions of the appendage wall ("high flow profile") or irregular, very low, peak filling and emptying waves (< 25 cm/s) associated with almost no visible appendage contractions ("low flow profile"). The left atrial appendage function in the first subgroup resembles that seen in patients with sinus rhythm, whereas the appendage function in the latter subgroup resembles more the "static pouch" seen in patients with rheumatic atrial fibrillation. Events suggestive of cardiogenic embolism occurred in six patients from group I, five of whom were in the low flow profile subgroup (p < 0.05). The spontaneous echo contrast phenomenon was observed in 80% of the low flow profile subgroup but in only 5% in the high flow profile subgroup (p < 0.05). Three thrombi confined to the left atrial appendage were detected by transesophageal echocardiography in group I; all three of the patients were in the low flow profile subgroup. CONCLUSIONS: The assessment of left atrial appendage function by transesophageal echocardiography may be helpful to identify subgroups of patients with nonrheumatic atrial fibrillation with an increased risk of thrombus formation.

Atrial Fibrillation↗

Spontaneous inversion of the left atrial appendage.

An interesting case of spontaneous inversion of the left atrial appendage was caused by an acute decrease in ventricular volume and the shortening of diastole during supraventricular tachycardia, creating a negative pressure invaginating the left atrial appendage. The return of normal in sinus rhythm and left-sided diastolic pressures reversed the left atrial appendage to a normal position, sparing the patient unnecessary surgery.

Echocardiography↗

Assessment of left atrial appendage function and its relationship to pulmonary venous flow pattern by transesophageal echocardiography.

We evaluated left atrial appendage function and its relationship to pulmonary venous flow in 53 patients divided into four groups. Group 1 consisted of 10 normal subjects. Group 2 included 15 patients with significant pure mitral stenosis in sinus rhythm. In group 3, there were 13 patients with pure significant mitral stenosis and atrial fibrillation. Group 4 consisted of 15 patients with normal mitral valve and atrial fibrilltion. We found significant decrease in left atrial appendage ejection fraction and maximum emptying flow velocity, velocity time integral of systolic pulmonary venous flow in Groups 2, 3 and 4 in comparison with normal subjects. Systolic pulmonary venous flow velocity was significantly decreased in Groups 3 and 4. There was significant correlation between left atrial appendage ejection fraction and peak emptying flow velocity (r = 0.62, P < 0,001). Systolic peak pulmonary venous flow velocity was significantly correlated with left atrial appendage ejection fraction and maximum emptying flow velocity (r = 0.67, P = 0,01; r = 0.58, P < 0,001, respectively). There was also significant correlation between systolic pulmonary venous flow velocity time integral and left atrial appendage ejection fraction (r = 0.66, P = 0.001). When normals were excluded from analysis, all the correlations were still significant. We concluded that left atrial appendage is a contractile structure, and that systolic pulmonary venous flow velocity is influenced by left atrial appendage dysfunction. Therefore left atrial appendage function needs to be considered when interpreting Doppler transmitral and systolic pulmonary venous flow patterns.

Adult↗

Is left atrial appendage flow a predictor for outcome of cardioversion of nonvalvular atrial fibrillation? A transthroacic and transesophageal echocardiographic study.

Accurate echocardiographic parameters for predicting the success of cardioversion or maintenance of sinus rhythm are poorly defined. This prospective transthoracic and transesophageal echocardiographic study was conducted to test the hypothesis that the left atrial appendage flow pattern could be a predictive parameter of the success of cardioversion and maintenance of sinus rhythm in patients with nonvalvular atrial fibrillation. Eighty-two consecutive patients with nonvalvular atrial fibrillation of <6 months' duration underwent transesophageal examination after transthoracic echocardiography. After exclusion of left atrial thrombus, pharmacologic (n = 18) or electrical (n = 64) cardioversion was successful in 75 of 82 patients. In the group that underwent successful cardioversion, maintenance of sinus rhythm (n = 35) or recurrence of arrhythmia (n = 40) was assessed during a 1-year follow-up. During transesophageal examination, five left atrial appendage thrombi were found, spontaneous echo contrast was present in 26 (32%) patients, and mean peak left atrial appendage emptying velocity was 35 +/- 18 cm/sec. Peak left atrial appendage emptying velocity was found to be statistically related to parameters of left ventricular and left atrial function but not to long-term maintenance of sinus rhythm. No other echocardiographic parameter was identified as a predictor for either the success of cardioversion or the maintenance of sinus rhythm at follow-up. In patients with nonvalvular atrial fibrillation of recent onset, peak left atrial appendage emptying velocity appears to be a complex parameter depending on left atrial and left ventricular function but that does not predict either the success rate of cardioversion or long-term maintenance of sinus rhythm after successful cardioversion.

Aged↗

Thoracoscopic obliteration of the left atrial appendage: potential for stroke reduction?

BACKGROUND: In a review of all relevant articles describing the site of left atrial thrombus in patients with atrial fibrillation, the thrombus was localized to the left atrial appendage in 43% of patients with rheumatic heart disease and in 91% of patients with nonrheumatic atrial fibrillation. This study was designed to test the feasibility of thoracoscopic obliteration of the left atrial appendage as a means of reducing thromboembolic stroke. METHODS: Thoracoscopic obliteration of the left atrial appendage was undertaken in 10 dogs, 5 with staples and 5 with an endoloop. Obliteration also was attempted in 8 fresh human cadavers. RESULTS: In all dogs, the appendage was rapidly obliterated (21.3 +/- 7.6 minutes) and confirmed at euthanasia at 11 weeks. In 3 cadavers, anatomic and disease factors prevented visualization of the left atrial appendage; in 1 the appendage tore, and in the remainder the appendage was obliterated. CONCLUSIONS: Obliteration of the left atrial appendage is feasible and may be considered as an additional surgical procedure to reduce stroke. The group of patients in whom it offers the greatest potential are those with atrial fibrillation deemed ineligible for warfarin, those without atrial thrombus and with a free pericardial and pleural space.

Animals↗

Diagnostic value of technetium-99m radionuclide angiography for detecting thrombosis in left atrial appendage.

In mitral valve disease, it is important to know whether thrombi are present in the left atrium when deciding upon a course of treatment. The left atrial thrombus usually locates in the left atrial appendage. In most cases of mitral valve disease, the left atrial appendage is clearly demonstrated by radionuclide angiography using 99mTc-labeled red blood cells and it can be speculated that the cases in which left atrial appendage are not demonstrated by RNA have left atrial thrombi. On the basis of this hypothesis, the diagnostic accuracy of radionuclide angiography to detect left atrial thrombi was evaluated retrospectively in 60 patients with mitral valve disease who had undergone surgery. The sensitivity of first-pass and equilibrium radionuclide angiography to detect left atrial thrombi was 83% and 67%, the specificity 79% and 54%, and the accuracy 80% and 57%, respectively. Although there were two false-negative cases in which the left atrial thrombi did not locate in the appendage and 10 false-positive cases in which left atrial appendages were not dilated, the negative predictive value was so high that a clearly demonstrated left atrial appendage can be translated into the absence of left atrial thrombi.

Adult↗