Is left atrial fibrosis an independent determinant of atrial fibrillation in mitral stenosis?

We prospectively studied whether left atrial (LA) fibrosis is a determinant of atrial fibrillation (AF) in mitral stenosis in patients who underwent balloon mitral valvotomy. There were 2 groups: Group A (n = 16), with AF and Group B (n = 27), without AF. Fibrosis was assessed by MRI. Patients underwent cardioversion before MRI. There were 27 females and 16 males, aged 29 ± 6 years. The LA areas in Groups A and B were 54.3 ± 4.4 mm² and 39.4 ± 2.3 mm² (p < 0.05) and the LA volume index was 46.2 ± 2.9 ml/m² vs 33 ± 3 ml/m² respectively (p < 0.0001). The presence of LA scarring was not statistically different in the two groups.     

Is left atrial appendage occlusion useful for prevention of stroke or embolism in atrial fibrillation?

Since in atrial fibrillation more than 90% of the thrombi are located in the left atrial appendage, an "elimination" of the left atrial appendage, either by resection or occlusion, seems an attractive alternative to oral anticoagulation. Although frequently regarded as an useless appendage, data from animal and human investigations show that the left atrial appendage may play an important role in the maintenance and regulation of the cardiac function, especially in arterial hypertension, atrial fibrillation, coronary heart disease, valvular heart disease and heart failure. Elimination of the left atrial appendage may impede thirst in hypovolemia, deteriorate hemodynamic responses to volume or pressure overload, decrease cardiac output and promote heart failure. Instead of preventing stroke, the consequences of left atrial appendage elimination may create new risk factors for stroke and thus might induce more harm than benefit to patients with atrial fibrillation. As long as the physiologic and pathophysiologic role of the left atrial appendage is not fully understood, left atrial appendage elimination should not be an alternative to oral anticoagulation.     

Surgical closure of the left atrial appendage - a beneficial procedure?

BACKGROUND: Closure of the fibrillating left atrial appendage (LAA) has been recommended during valve surgery to decrease the risk of arterial embolism. However, patients undergoing surgical LAA closure have not systematically been reevaluated for complete LAA obliteration. METHODS AND RESULTS: During a 12-month period, we studied 6 consecutive patients with paroxysmal (n = 3) or permanent (n = 3) atrial fibrillation who underwent surgical LAA closure at the time of valve surgery. Transesophageal echocardiography (TEE) performed 23-159 days (mean 51) postoperatively demonstrated complete LAA closure in only 1 patient. In 5 patients, incomplete LAA closure was found due to disruption of the closure line. The size of the residual LAA orifice ranged from 3 to 20 mm. There was a high flow velocity at the LAA orifice (0.33-2.2 m/s), whereas flow in the LAA body was low (<0.2 m/s). Spontaneous echocardiographic contrast (SEC) in the LAA had newly developed (n = 3) or was much more intense than preoperatively (n = 2). Despite therapeutic anticoagulation 2 patients showed a LAA thrombus which had not been present on the preoperative TEE, and 1 patient with SEC suffered a stroke 4 weeks after attempted LAA closure. CONCLUSION: Surgical LAA closure was incomplete in most patients, resulting in blood stagnation and an increased likelihood of clot formation. Incomplete surgical LAA closure, therefore, may promote rather than reduce the risk of stroke. Intraoperative TEE is mandatory to verify complete LAA obliteration.     

An unusual combination of left atrial myxoma and left ventricular non-compaction cardiomyopathy in a male patient: A Casereport

Left atrialmyxoma is a common primary cardiac tumor that is accompanied by organic heart diseases.But left atrial myxoma coexistent with left ventricular non-compaction(LVNC) is extremely rare. A young male patient with left atrial myxoma and LVNC was reported in this study. A 25-year-old manpresented to the emergency department with sudden shortness of breath and syncope, accompanied by fever and cough. He had a history ofacute ischemic strokeone year before hospitalization. Echocardiography re...     

Clinical follow-up of left atrial appendage occlusion in patients with atrial fibrillation ineligible of oral anticoagulation treatment—a systematic review and meta-analysis

Journal of Interventional Cardiac Electrophysiology - The recommended stroke prevention for patients with atrial fibrillation (AF) and increased risk of ischemic stroke is oral anticoagulation...     

Pulmonary vein dilatation: another possible crosslink between left atrial enlargement and atrial fibrillation?

The interplay between left atrial (LA) dilatation and atrial fibrillation (AF) has been well established, but the underlying mechanisms of this vicious circle are not fully understood. Recent studies indicated that pulmonary vein (PV) dilatation is implicated in the development of AF. On the other hand, PV dilatation has been associated with LA dilatation. It is therefore reasonable to assume that PV dilatation represents a common pathophysiologic pathway between LA enlargement and AF.     

How should left atrial size be reported? Comparative assessment with use of multiple echocardiographic methods

Background

Determination of left atrial (LA) size is important in clinical decision-making. The LA anteroposterior dimension (APD) has been routinely reported as LA size assessment. Early studies indicated that the APD may have limited accuracy in quantification. Conventional 3-dimensional reconstruction (C3DR) of the LA has been validated. However, its process is time-consuming and not applicable for daily practice. To explore an accurate and practical approach, we compared different echocardiographic measurements with C3DR in 141 patients with different LA sizes.

Methods and results

LA size was measured with (1) the cubic equation with APD (Cub); (2) the ellipsoidal formula (Ellp); (3) biplane modified Simpson rule (biplane); and (4) simplified 3-dimensional reconstruction from 3 standard apical views with B spline interpolation (S3VR). All four methods were compared with C3DR. S3VR and biplane methods provided a close agreement to C3DR (y = 0.94x + 3.6, r = 0.95, SEE = 7.6 mL, mean difference = −1.3% for S3VR; y = 0.87x + 2.9, r = 0.91, SEE = 9.0 mL, mean difference = −9.4% for biplane). The Cub and Ellp calculations were less accurate, with significant volume underestimation (P < .001).

Conclusions

LA single dimension is not accurate for LA size measurement. Among four different methods of LA size measurement, biplane and S3VR provide the closest agreement to C3DR. The biplane, which is readily applicable with current echocardiographic equipment, should be routinely applied in clinical practice.     

Is the left atrial appendage more than a simple appendage?

The left atrial appendage (LAA) is a cardiac structure with unique anatomic and functional features. It is significantly more than a simple chamber appended to the left atrium (LA), differing from the LA in structure, function, and hormonal activity. Unfortunately, it is the source of more than 90% of cardiac‐based emboli, particularly in atrial fibrillation, mandating lifelong anticoagulation. Percutaneous LAA exclusion was developed to limit or eliminate cardioembolic events in patients with atrial fibrillation. Benign healing of the appendage occurs without adverse hemodynamic effects, and with no residual surface thrombus or tissue damage. The feasibility of this treatment is now established, suggesting that percutaneous therapy is safe, practical and possibly effective to eliminate the need for anticoagulation and significantly reduce cardioembolic events. © 2009 Wiley‐Liss, Inc.     

Is the site of thrombus formation in the left atrial appendage associated with the risk of cerebral embolism?

Atrial fibrillation (AF) is a risk factor for cerebral embolism, with the left atrial appendage (LAA) being considered as the source of emboli. However, the relationship between the histologic properties of LAA thrombi and the occurrence of cerebral embolism is not known. Seventy-six hearts from patients who died within 1 month after cerebral embolism were studied at autopsy. Patients were grouped according to the presence of AF and the presence of valvular disease (VD). We determined whether the LAA thrombi adhered to the trabecular region or the remainder of the LAA. LAA thrombi were grouped into three stages: a fresh stage in which thrombi consisted of fibrin and platelets, an organizing stage in which angiogenesis was observed in the thrombi, and an organized stage in which endothelial cells covered the surface of the thrombi. The AF+/VD- group included 19 patients (25.0%), the AF+/VD+ group 8 (10.5%), the AF-/ VD- group 37 (48.7%), and the AF-/VD+ group included 12 patients (15.8%). LAA thrombi were observed in 15 patients (78.9%) in the AF+/VD- group, and all of the thrombi adhered to the trabecular region. Thrombi in the fresh and the organizing stages were observed in 10 patients (66.7%). Patients in the AF+/VD- group accounted for about 25% of the cases of cerebral embolism. All of these thrombi were attached to the trabecular region, and about 70% of them could represent an embolic source.