Transoesophageal echocardiography-guided cardioversion of atrial fibrillation or flutter. Selection of a low-risk group for immediate cardioversion.

AIMS: Despite exclusion of left atrial thrombi by transoesophageal echocardiography, cardioversion-related thromboembolism has been reported in atrial fibrillation or flutter. To define a low-risk group for cardioversion without previous anticoagulation, patients were selected for immediate cardioversion if there were no thrombi, no echo spontaneous contrast and the outflow velocity of the left atrial appendage was greater than 0.25 m. s(-1)on transoesophageal echocardiography. METHODS AND RESULTS: Two hundred and forty-two consecutive patients referred for cardioversion of atrial fibrillation or flutter with a duration of more than 2 days and no anticoagulation therapy were examined with transoesophageal echocardiography. After the transoesophageal echocardiography examination, patients who were eligible for immediate cardioversion were anticoagulated with low molecular weight heparin (dalteparin) subcutaneously, together with warfarin prior to cardioversion. Dalteparin treatment was continued until the patient had reached therapeutic prothrombin values. Based on the transoesophageal echocardiographic findings the patients were divided into two groups: immediate cardioversion, group A, with a mean age of 62+/-13 years (n=162); or conventional warfarin treatment before cardioversion, group B, with a mean age of 67+/-10 years (P<0.05) (n=80). In group A, lone atrial fibrillation or flutter was more common (53%; 95% CI: 45-61) compared to group B (34%; 95% CI: 23-44, P<0.05), while heart disease was more common in group B (45%; 95% CI: 34-56) compared to group A (31%; 95% CI: 24-39, P<0.05). Echocardiography revealed thrombi in 5% (95% CI: 2.6-8) of the patients, left atrial size was larger, fractional shortening lower, and a higher proportion had impaired left ventricular function in group B. No thromboembolic event occurred at or after cardioversion in any of the patients; however, before planned cardioversion one transitory ischaemic attack, one lethal stroke and one cardiac death occurred in three of the patients with thrombi despite warfarin therapy. One-month follow-up maintenance of sinus rhythm was 75% in group A compared to 45% in group B (P<0.01). CONCLUSION: After using our transoesophageal echocardiographic exclusion criteria (no thrombi, no spontaneous echo contrast and left atrial appendage outflow velocity > or = 25 m. s(-1)) cardioversion can safely be performed in 2/3 of patients with atrial fibrillation or flutter without previous anticoagulation therapy. These patients maintained sinus rhythm significantly better after 1 month compared to patients with prolonged warfarin therapy before cardioversion.     

Importance of left atrial appendage flow as a predictor of thromboembolic events in patients with atrial fibrillation.

AIM: The purpose of this study was to investigate the role of transoesophageal echocardiography in predicting subsequent thromboembolic events in patients with atrial fibrillation. METHODS AND PATIENTS: Transoesophageal echocardiography was performed in 88 patients with documented paroxysmal (n=53) or chronic atrial fibrillation (n=35) to assess morphological and functional predictors of thromboembolic events. Prospective selection was from patients with non-valvular atrial fibrillation who had undergone transoesophageal echocardiography because of previous thromboembolism (n=30); prior to electrical cardioversion (n=31); or for other reasons (n=27). All patients were followed up for 1 year. RESULTS: During the period of follow-up new thromboembolic events occurred in 18 of 88 patients (20%/year); 16 of these patients had a stroke and two a peripheral embolism. Univariate analysis revealed that previous thromboembolism (P<0.005; odds ratio 5.3 [CI 1.9, 12. 1]), history of hypertension (P<0.01; odds ratio 4.0 [CI 1.4, 10.4), presence of left atrial spontaneous echo contrast (P<0.025; odds ratio 3.5 [CI 1.2, 10.0]), and presence of left atrial appendage peak velocity 相似文献   

Visualization of left atrial appendage and assessment of its function by transthoracic second harmonic imaging and contrast-enhanced pulsed Doppler.

BACKGROUND: Low flow velocity within the left atrial appendage, as assessed by transoesophageal echocardiography, is a predictor of thromboembolism and of a low success rate of cardioversion of atrial fibrillation. However, the semi-invasive nature does limit its serial application as a screening technique. METHODS AND RESULTS: We investigated the value of transthoracic second harmonic echocardiography and pulsed Doppler at baseline and after intravenous contrast injection to visualize the left atrial appendage and assess blood flow velocities within its cavity. We studied 51 consecutive patients undergoing transoesophageal echocardiography. After transoesophageal echocardiography, transthoracic second harmonic imaging was performed and the left atrial appendage was visualized in 46 patients. Interpretable pulsed Doppler tracings of left atrial appendage flow were obtained at baseline in 39 patients and in 45 patients during Levovist administration. The correlations between peak emptying velocity of left atrial appendage as measured by transoesophageal echocardiography and by transthoracic standard and contrast-enhanced Doppler were 0.81 and 0.91, respectively. The agreement between transoesophageal echocardiography and transthoracic contrast-enhanced pulsed Doppler echocardiography in classifying left atrial appendage flow velocity patterns was 93%. Left atrial appendage thrombus was detected by transthoracic second harmonic imaging in only one of the eight patients shown by transoesophageal echocardiography to have a thrombus. However, all but one of the patients with left atrial appendage thrombus and/or spontaneous echocardiographic contrast at transoesophageal echocardiography had <30cm/s left atrial appendage flow velocity by transthoracic Doppler. CONCLUSIONS: This study shows that left atrial appendage can be visualized by transthoracic second harmonic imaging and that the flow velocity within its cavity is reliably measured by pulsed Doppler in a substantial fraction of patients. Contrast enhancement improves the feasibility and the accuracy of transthoracic evaluation of left atrial appendage flow velocity. The practical value of these results in predicting thromboembolic risk and success of cardioversion of atrial fibrillation needs to be proved by prospective studies.     

Left atrial appendage emptying velocity does not predict postoperative atrial fibrillation in patients undergoing cardiopulmonary bypass.

BACKGROUND: Atrial fibrillation is a common complication of cardio-pulmonary bypass and improved pre-operative risk assessment could help guide prophylactic therapy. This study examined whether reduced left atrial appendage flow velocities measured by transoesophageal echocardiography pre-operatively in patients in sinus rhythm predicted development of postoperative atrial fibrillation. METHODS AND RESULTS: All patients who underwent transoesophageal echocardiography for clinical indications with measurements of left atrial appendage velocities within twelve months prior to cardio-pulmonary bypass were retrospectively identified. Postoperative records were reviewed and the patients divided into two groups based on the presence or absence of clinically significant atrial fibrillation during hospitalization following cardio-pulmonary bypass. Thirty-six patients (mean age 61.1 +/- 14.8 years, 18M/18F) were included in the study. The overall incidence of atrial fibrillation in the cohort was 17/36 patients (47%). Mean left atrial appendage emptying velocity was 50.8 +/- 23.3 cm/s2 (range 26-119) in the patients with sinus rhythm only and 41.5 +/- 16.7 cm/s2 (range 16-76), in the patients with postoperative atrial fibrillation (P=ns). CONCLUSIONS: In our patient population there was no significant difference in left atrial appendage emptying velocity measured by transoesophageal echocardiography in patients with and without postoperative atrial fibrillation. Pre-operative measurement of left atrial appendage emptying velocity cannot be relied upon to risk stratify patients prior to cardio-pulmonary bypass.     

Transthoracic Doppler echocardiographic measurement of left atrial appendage blood flow velocity: comparison with transoesophageal measurement.

AIM: We validated transthoracic echocardiographic measurements of left atrial appendage flow velocity by comparing them with transoesophageal echocardiographic measurements. METHODS AND RESULTS: Eighty-four consecutive patients (mean age, 64.6 years) with various cardiac diseases, who underwent both transthoracic echocardiography and transoesophageal echocardiography were studied. Thirty-two patients were in sinus rhythm, and the remaining 52 patients were in atrial fibrillation. On transthoracic echocardiography, the transducer was placed somewhat superior and outside from the position viewing the conventional parasternal short-axis image of the aortic valve, so that the angle between left atrial appendage midline and Doppler beam could be narrowed. The left atrial appendage flow velocity pattern was recorded by pulsed Doppler mode with a sampling volume placed at the left atrial appendage orifice on both transthoracic echocardiography and transoesophageal echocardiography. In both approaches, the peak emptying velocity (LAA-E) and the peak filling velocity (LAA-F) of the left atrial appendage were measured. In sinus rhythm, the LAA-E was detectable in 25 of the 32 patients (78.1%) and the LAA-F in 20 of the 32 patients (62.5%). Both LAA-E and LAA-F were detectable in 46 of the 52 patients (88.5%) in atrial fibrillation. Good correlations of LAA-E and LAA-F were observed between transthoracic echocardiography and transoesophageal echocardiography measurements in sinus rhythm (r=0.94, r=0.95, respectively; both, P<0.0001) and in atrial fibrillation (r=0.89, r=0.95, respectively; both, P<0.0001). CONCLUSIONS: The left atrial appendage flow velocities could be sufficiently recorded and assessed by transthoracic echocardiography in 84 Japanese unselected consecutive patients with sinus rhythm or atrial fibrillation.     

Pulmonary vein flow analysis by transoesophageal echocardiogr phy in patients with chronic atrial fibrillation; 1 year follow-up after cardioversion.

AIMS: Left and right upper pulmonary vein flow can be adequately recorded by transoesophageal Doppler echocardiography. The aim of this study was to investigate whether analysis of the pulmonary venous flow velocity pattern can predict the long-term maintenance of sinus rhythm after successful cardioversion of chronic atrial fibrillation. METHODS AND RESULTS: Thirty-six consecutive patients, aged 53+/-9 years, with chronic atrial fibrillation of 5.33+/-2 months duration, were subjected to transoesophageal Doppler echocardiography to record left and right upper pulmonary venous flow, 24 h and 3 months following successful cardioversion. One year following cardioversion, 12 patients (33.3%) were in sinus rhythm (sinus rhythm group) while the remaining 24 patients were in atrial fibrillation (atrial fibrillation group). At 24 h following cardioversion, biphasic systolic forward flow in the left and/or right upper pulmonary venous flow velocity was detected in 10 patients of the sinus rhythm group and in four patients of the atrial fibrillation group (P<0001). The systolic fraction was significantly higher in the sinus rhythm group, 0.48+/-0.04 and 0.39+/-0.06, P<0.001 for the left upper pulmonary venous flow, and 0.52+/-0.05 and 0.41+/-0.04, P<0.001 for the right upper pulmonary venous flow, respectively. In patients who displayed a biphasic systolic forward flow and in whom the right upper pulmonary venous flow systolic fraction was higher than 0.50 at 24 h post-cardioversion, the probability of maintenance of sinus rhythm at 1 year exceeded 95%. CONCLUSION: The detection of a biphasic systolic forward flow in the pulmonary venous flow velocity, and of a right upper pulmonary vein systolic fraction higher than 0.50 as early as 24 h following cardioversion of chronic atrial fibrillation, identifies patients who will remain in sinus rhythm 1 year after cardioversion.     

Echocardiographic factors predictive of restoration and maintenance of sinus rhythm after reduction of atrial fibrillation

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia. While the arrhythmia was initially thought to be little more than a nuisance, it is now clear that AF has a significant negative impact on quality of life and a corresponding increase in both morbidity and mortality. OBJECTIVE: The aim of this study was to identify Doppler echographic patterns that allow prediction of atrial fibrillation reduction and maintenance of sinus rhythm within 12 months. PATIENTS AND METHODS: One hundred and thirty patients having permanent atrial fibrillation, recent (51) or chronic (79) are included in the study, excepting those with valvular heart disease or thyroid dysfunction. The mean age was 63.5 +/- 11.3 years. Both transthoracic and transoesophageal echocardiography was performed using a Philips SONOS 5500 Echograph, before cardioversion. Were studied: end diastolic and systolic left ventricular diameters, left ventricular ejectionnal fraction, left atrial area (LAA), left atrial diameter, left atrial appendage area and peak emptying velocities of the left atrial appendage (PeV). Sinus rhythm was re-established in 102 patients (44 having recent and 58 chronic atrial fibrillation). Sinus rhythm was maintained for 12 months in 79 patients. RESULTS: Within the echographic parameters studied, the left atrial area (LAA) and peak emptying velocities of left atrial appendage (PeV) before cardioversion were the best predictors of restoration of sinus rhythm. On monovariate analysis, SOG is significantly lower and PicV is significantly higher in patients whose sinus rhythm had been restored in comparison with those with permanent atrial fibrillation. (Mean SOG: 27.7 +/- 7.62 vs. 34 +/- 7,6 cm2, p<0.0001; Mean PicV: 44 +/- 15.8 vs. 31.4 +/- 13,7 cm/s, p<0.0001). This difference was maintained on multivariate analysis (p=0.002 for SOG and p=0.005 for PicV). In patients with recent atrial fibrillation, only left atrial area can predict on mono and multivariate analysis (p=0.05, OR=0.5, IC=0.36 à 3.56), re-establishing of sinus rhythm whereas in patients with chronic atrial fibrillation, peak emptying velocity of left atrial appendage predict better re-establishing of sinus rhythm (p=0.04, OR=1.29, IC=0.12 à 4.23). The threshold values of LAA and PeV for conversion of atrial fibrillation into sinus rhythm are respectively 25 cm2 and 20 cm/sec. In patients who converted into sinus rhythm; LAA predict maintenance of sinus rhythm at the end of 12 months of survey (p=0.04) with a threshold value of 25 cm2. In the subgroup of patients admitted with chronic atrial fibrillation, PeV predicts better the maintenance of sinus rhythm (p=0.05) with a threshold value of 60 cm/sec, p=0.06; whereas LAA remains better in patients with a recent atrial fibrillation. (p=0.02). CONCLUSION: In addition to the anatomic study of cardiac structure and the search of intracavitary thromboses before reduction of atrial fibrillation, echocardiography allows prediction of cardioversion success (LAA and PeV) and maintenance of sinus rhythm within 12 months.     

Prediction of left atrial appendage thrombi in non-valvular atrial fibrillation.

AIMS: There is little knowledge about the predictors of left atrial appendage (LAA) thrombi in non-valvular atrial fibrillation (NVAF). We investigated the ability of D-dimer to predict LAA thrombi. METHODS AND RESULTS: In this study, 925 patients with NVAF were enrolled. At the time of transoesophageal echocardiography (TEE), D-dimer levels were measured simultaneously. Significant independent predictors of LAA thrombi were the presence of congestive heart failure [odds ratio (OR) 3.10, 95% confidence interval (CI) 1.77-5.50, P < 0.0001), a history of recent embolic events (OR 3.39, 95% CI 1.90-6.04, P < 0.0001), and D-dimer levels (OR 97.6, 95% CI 17.3-595.8, P < 0.0001). Receiver operating characteristic analysis yielded an optimal cutoff value of 1.15 microg/mL for D-dimer to detect LAA thrombi. LAA thrombi were detected in 21.8% of patients with higher D-dimer values, whereas it was detected in only 3.1% of patients with lower D-dimer values. D-dimer cutoff level of 1.15 microg/mL had a negative predictive value of 97% for identifying LAA thrombi. CONCLUSION: In patients with NVAF, D-dimer may be helpful for predicting the absence of LAA thrombi. D-dimer level was clinically useful to guide the management of patients with NVAF, especially for those complicated with congestive heart failure and/or recent embolic events.     

Value and indications of transesophageal echocardiography before cardioversion of atrial fibrillation

Transoesophageal echocardiography is essential for the diagnosis of left atrial thrombosis and its precursors (dense spontaneous contrast--reduced auricular emptying velocities) and for the diagnosis of complex aortic atheroma. The sensitivity and specificity of transoesophageal echocardiography for the diagnosis of left atrial thrombus are about 100% and about 90% for that of aortic atheroma. The formal indications for transoesophageal echocardiography before cardioversion are: atrial fibrillation complicated by stroke or a recent systemic embolism: atrial fibrillation complicated by mitral valve disease as the thrombo-embolic risk is major in this context: atrial fibrillation with a high thromboembolic risk: a history of stroke, presence of cardiac failure, diabetes, permanent hypertension, a very dilated left atrium (> or = 50 mm): apparently isolated atrial fibrillation for which long term anticoagulant therapy is hoped to be avoided. On the other hand, in recent, uncomplicated, non-valvular atrial fibrillation, a common fallacy should be corrected: transoesophageal echocardiography does not improve the safety of electrical cardioversion. With similar durations of prior anticoagulant therapy. Over a 3 week period, the frequency of thromboembolic complications is the same whether or not transoesophageal echocardiography is performed before cardioversion (0.8% in both groups of the SEIDL study). With short periods of anticoagulant therapy before cardioversion, there is a higher thromboembolic complication and mortality rate (ACUTE study). The safety of cardioversion is not related to the practice of prior transoesophageal echocardiography but to strict and efficacious anticoagulation for a period of 3 weeks before cardioversion.     

Predictors of left atrial appendage clot: a transesophageal echocardiographic study of left atrial appendage function in patients with severe mitral stenosis

BACKGROUND: The purpose of this study was to prospectively evaluate a large group of consecutive, non-anticoagulated patients with severe rheumatic mitral stenosis and to analyze the left atrial appendage function in relation to left atrial appendage clot and spontaneous echo contrast formation. METHODS AND RESULTS: We prospectively studied left atrial appendage function in 200 consecutive patients with severe mitral stenosis who underwent transesophageal echocardiography and correlated it with spontaneous echo contrast and left atrial appendage clot. The mean age was 30.2 +/- 9.4 years. Fifty-five (27.5%) patients were in atrial fibrillation. Left atrial appendage clot was present in 50 (25%) patients and 113 (56.5%) had spontaneous echo contrast. The older age, increased duration of symptoms, atrial fibrillation, spontaneous echo contrast, larger left atrium, depressed left atrial appendage function and type II and III left atrial appendage flow patterns correlated significantly (p<0.05) with the left atrial appendage clot. Left atrial appendage ejection fraction was significantly less in patients with clot (21.8 +/- 12.8% v. 39.1 +/- 13.2%, p<0.0001) and in those with spontaneous echo contrast (30.3 +/- 16.2 % v. 40.3 +/- 11.8%, p<0.001). Left atrial appendage filling (18.0 +/- 11.7 v. 27.6 +/- 11.8 cm/s, p <0.0001) and emptying velocities (15.4 +/- 7.0 v. 21.5 +/- 9.6 cm/s, p<0.001) and filling (1.4 +/- 1.0 v. 2.5 +/- 1.4 cm, p<0.0001) and emptying (1.5 +/- 1.2 v. 2.1 +/- 1.2 cm, p <0.05) velocity time integrals were also significantly lower in patients with clot as compared to those without clot. On multivariate regression analysis, atrial fibrillation (odds ratio 6.68, 95% CI 1.85-24.19, p=0.003) and left atrial appendage ejection fraction (odds ratio 1.06, 95% CI 1.00 - 1.11, p=0.04) were the only two independent predictors of clot formation. Incidence of clot was 62.59% in patients with left atrial appendage ejection fraction < or = 25% as compared to 10.4% in those having left atrial appendage ejection fraction >25%. Similarly patients with spontaneous echo contrasthadlower filling (21.7 +/- 11.5 v. 29.4 +/- 12.7 cm/s, p<0.0001) and emptying (17.0 +/- 8.1 v. 23.9 +/- 10.9 cm/s, p<0.0001) velocities, as well as filling (1.9 +/- 1.3 v. 2.7 +/- 1.3 cm, p<0.01) and emptying (1.7 +/- 1.0 v. 2.3 +/- 1.4 cm, p<0.01) velocity time integrals as compared to patients without spontaneous echo contrast. In a subgroup of the patients with normal sinus rhythm, the left atrial appendage ejection fraction was significantly less in patients with clot compared to those without clot (31.2 +/- 13.2 v. 41.3 +/- 11.5 %, p<0.01). CONCLUSIONS: In the patients with severe mitral stenosis, besides atrial fibrillation, a subgroup of patients in normal sinus rhythm with depressed left atrial appendage function (left atrial appendage ejection fraction < or = 25%) had a higher risk of clot formation in left atrial appendage and these patients should be routinely anticoagulated for prevention of clot formation.     

Clinical value of left atrial appendage flow for prediction of long-term sinus rhythm maintenance in patients with nonvalvular atrial fibrillation

OBJECTIVES: This study evaluated the role of various clinical and echocardiographic parameters, including the left atrial appendage (LAA) anterograde flow velocity, for prediction of the long-term preservation of sinus rhythm (SR) in patients with successful cardioversion (CV) of nonvalvular atrial fibrillation (AF). BACKGROUND: Echocardiographic parameters for assessing long-term SR maintenance after successful CV of nonvalvular AF are not accurately defined. METHODS: Clinical, transthoracic echocardiographic and transesophageal echocardiographic (TEE) data--measured in AF lasting >48 h--of 186 consecutive patients (116 men, mean age: 65 +/- 9 years) with successful CV (electrical or pharmacologic) were analyzed for assessment of one-year maintenance of SR. RESULTS: At one-year follow-up, 91 of 186 (49%) patients who underwent successful CV continued to have SR. Mean LAA peak emptying flow velocity was higher in patients remaining in SR for one year than in those with AF relapse (41.7 +/- 20.2 cm/s vs. 27.7 +/- 17.0 cm/s; p < 0.001). On multivariate logistic regression analysis, only the mean LAA peak emptying velocity >40 cm/s (p = 0.0001; chi(2): 23.9, odds ratio [OR] = 5.2, confidence interval [CI] 95% = 2.7 to 10.1) and the use of preventive antiarrhythmic drug treatment (p = 0.0398; chi(2): 4.2; OR = 2.0, CI 95% = 1.0 to 3.8) predicted the continuous preservation of SR during one year, outperforming other univariate predictors such as absence of left atrial spontaneous echocardiographic contrast during TEE, the left atrial parasternal diameter <44 mm, left ventricular ejection fraction >46% and AF duration <1 week before CV. The negative and positive predictive values of the mean LAA peak emptying velocity >40 cm/s for assessing preservation of SR were 66% (CI 95% = 56.9 to 74.2) and 73% (CI 95% = 62.4 to 83.3), respectively. CONCLUSIONS: In TEE-guided management of nonvalvular AF, high LAA flow velocity identifies patients with greater likelihood to remain in SR for one year after successful CV. Low LAA velocity is of limited value in identifying patients who will relapse into AF.     

Stunning of the left atrium after pharmacological cardioversion of atrial fibrillation

INTRODUCTION: Stunning of the left atrium and atrial appendage is a well known but not fully clarified phenomenon observed during the cardioversion of atrial fibrillation regardless of the cardioversion method attempted. AIM: To assess the effects of propafenone and amiodarone on left atrium and left atrial appendage contractility. METHODS: Forty patients with paroxysmal atrial fibrillation (20 females, 20 males), aged 60-83 (mean 72.0+/-10.1) years, were enrolled into the study. Half of these patients had sinus rhythm restored by the administration of oral propafenone (150-300 mg) and the remaining 20 patients were treated with intravenous amiodarone (150-450 mg). The control group consisted of 20 patients (10 females, 10 males) aged 52-78 (mean 61.2+/-9.3) years with sinus rhythm and no history of atrial fibrillation. All the patients had a transthoracic (TTE) and transesophageal (TEE) echocardiography performed while still in the AF, before drug administration and 1 hour after sinus rhythm restoration. RESULTS: All haemodynamic parameters of the left atrium measured after the sinus rhythm restoration were significantly worse when compared with the control group. Left atrial fractional shortening and total atrial fraction were significantly lower after propafenone than amiodarone (8.6+/-3.6% vs 11.7+/-5.5%, p<0.05; and LA FC 16.2+/-5.3% vs 23.3 (+/-6.3)% respectively, p<0.05). Doppler echocardiographic parameters included in the analysis such as mitral flow and superior left pulmonary vein flow were significantly lower in the sinus rhythm restoration group than in the control group. Among them the end-diastolic mitral flow velocity amplitude and flow velocity integral as well as the maximum pulmonary retrograde velocity were significantly worse in the group treated with propafenone than in patients receiving amiodarone. All the atrial appendage Doppler velocity parameters were significantly reduced after the sinus rhythm restoration in both groups. In the patients treated with propafenone, values of these parameters were significantly decreased compared with the patients receiving amiodarone. CONCLUSIONS: Successful pharmacological cardioversion of atrial fibrillation causes the left atrium and left atrial appendage contractility impairment similar to that observed with other methods of the sinus rhythm restoration. Following the AF cardioversion the level of left atrial stunning is higher in the patients treated with propafenone than in subjects receiving amiodarone.     

Left atrial appendage function in patients with atrial flutter.

OBJECTIVE: To determine whether echocardiographic markers thromboembolic risk differ between patients with pure atrial flutter and patients with atrial flutter and intermittent atrial fibrillation. DESIGN: Patients with atrial flutter were followed up prospectively for 12 months to identify intermittent atrial fibrillation. After the follow up period, transthoracic and multiplane transoesophageal echocardiography were performed to assess left atrial chamber and appendage size, peak emptying velocities, and emptying fraction of the left atrial appendage. The presence of spontaneous echo contrast was also determined. SETTING: Tertiary cardiac care centre. PATIENTS: 20 consecutive patients with atrial flutter; 11 healthy subjects in sinus rhythm served as controls. RESULTS: Intermittent atrial fibrillation was documented in 11 patients by Holter monitoring or surface ECG; atrial fibrillation was not found in the other nine patients. Compared with the patients with pure atrial flutter, patients with atrial flutter and intermittent atrial fibrillation had larger left atrial chamber (mean (SD) 4.5 (0.6) v 3.8 (0.5) cm; 95% confidence interval 0.2 to 1.2; P = 0.01) and appendage areas (6.7 (2.2) v 4.8 (4.9) cm; 95% CI 0.4 to 3.5; P = 0.02), lower left atrial appendage emptying fractions (33 (11)% v 52 (11)%; 95% CI 8 to 29; P = 0.008), and also lower left atrial appendage emptying velocities (0.44 (0.21) v 0.79 (0.27) m/s; 95% CI 0.13 to 0.56; P = 0.005). In addition, a higher incidence of spontaneous echo contrast (11% v 36%) was observed in patients with atrial flutter and intermittent atrial fibrillation. CONCLUSIONS: Left atrial appendage function is depressed and spontaneous echo contrast more frequent in patients with atrial flutter and intermittent atrial fibrillation, as opposed to patients with pure atrial flutter. These data support the concept that patients with atrial flutter and intermittent atrial fibrillation have an increased risk of thromboembolic events and should therefore receive adequate anticoagulant treatment.     

Effect of low-dose isoproterenol infusion on left atrial appendage function soon after cardioversion of chronic atrial tachyarrhythmias

BACKGROUND: Cardioversion of chronic atrial fibrillation or atrial flutter to sinus rhythm is often associated with transient atrial mechanical dysfunction, i.e. 'atrial stunning', which may increase the risk of subsequent thromboembolic events. We hypothesized that, because of its positive inotropic action, a low-dose isoproterenol infusion might improve postcardioversion atrial mechanical function. METHOD: Eighteen patients (15 male, three female; 12 atrial fibrillation, six atrial flutter; mean age 65+/-10 years) exhibiting atrial postcardioversion stunning were included in the study. Isoproterenol was infused for 10 min at a dose sufficient to increase the heart rate by about 10%. Using transesophageal echocardiography, both the left atrial appendage emptying/filling flow velocity and function (fractional area change) were examined at baseline, before isoproterenol (immediately after cardioversion) and after isoproterenol. RESULTS: With infusion of 0.005-0.008 microg/kg/min isoproterenol, heart rate increased by 11.1+/-2.9%, and left atrial appendage emptying velocity, which was diminished following cardioversion, increased significantly (P<0.001) (baseline, before and after isoproterenol: 41.1+/-18.0, 20.3+/-8.5 and 27.3+/-9.6 cm/s, respectively). No major complications were associated with isoproterenol infusion. CONCLUSIONS: Short-term infusion of low-dose isoproterenol improved atrial function after cardioversion of chronic atrial fibrillation and atrial flutter.     

Early cardioversion of atrial fibrillation and atrial flutter guided by transoesophageal echocardiography: a single centre 8.5-year experience.

AIMS: To analyse the safety and impact on maintenance of sinus rhythm of transoesophageal echocardiographically guided early cardioversion associated with short-term anticoagulation in a large series of patients with atrial fibrillation and atrial flutter. METHODS AND RESULTS: Patients who were candidates for cardioversion were eligible for inclusion if they had atrial fibrillation or atrial flutter lasting longer than 2 days or of unknown duration. Patients received short-term anticoagulation with warfarin or heparin and underwent transthoracic echocardiography followed by transoesophageal echocardiography. Early cardioversion was performed if no thrombus was seen on the transoesophageal study. Warfarin was maintained for 1 month after cardioversion. In patients with atrial thrombi, cardioversion was deferred and prolonged anticoagulation was prescribed. The study population included 183 patients. One hundred and sixty nine patients without atrial thrombi underwent early cardioversion. Fourteen patients with atrial thrombi (7.6%) underwent a second transoesophageal echocardiogram after a median of 4 weeks of oral warfarin, and cardioversion was performed if clot regression was documented. No patient in our study population had a clinical thromboembolic event at 1 month follow-up (95% C.I. 0-0.016). The immediate success rate of cardioversion was better among patients with atrial fibrillation < 4 weeks duration compared with patients with atrial fibrillation of longer or of unknown duration: 96.6% vs 85%, respectively (P = 0.014). At 1 month follow-up, the percentage of arrhythmia relapses in patients with initially successful cardioversion was similar in the two groups (29% vs 26%, P = ns); thus the initial better outcome in patients with recent-onset arrhythmia was not lost. CONCLUSION: Transoesophageal echocardiography-guided early cardioversion in concert with short-term anticoagulation is safe. This approach permits abbreviation of the overall duration of atrial fibrillation and has a better impact on the maintenance of sinus rhythm for patients in whom the duration of atrial fibrillation is < 4 weeks.     

Lipoprotein(a), left atrial appendage function and thromboembolic risk in patients with chronic nonvalvular atrial fibrillation

Lipoprotein(a) (Lp(a)) has a prothrombotic effect by modulating the fibrinolytic system. The purpose of the present study was to determine whether serum Lp(a) levels are associated with an increased risk of thromboembolism in chronic nonvalvular atrial fibrillation (NVAF). Clinical, laboratory and transesophageal echocardiographic data were collected in 172 consecutive, non-anticoagulated patients with chronic NVAF. Thirty-four patients (thromboembolic group) had a recent (<1 month) embolic event and/or a left atrial thrombus on transesophageal echocardiography. The thromboembolic group had a higher frequency of spontaneous echo contrast (94 vs. 58%, p<0.0001), increased concentrations of Lp(a) (median: 31.5 vs. 15.5 mg/dl, p<0.0001) and fibrinogen (median: 352 vs. 314 mg/dl, p = 0.0015), larger left atrial dimensions (median: 5.1 vs. 4.8cm, p = 0.0078), and reduced left atrial appendage (LAA) flow velocities (median: 9.5 vs. 21.2 cm/s, p<0.0001) than the nonthromboembolic group. Multivariate analysis identified 3 independent predictors of thromboembolism: Lp(a) level > or =30 mg/dl (odds ratio (OR) 9.5, 95% confidence interval (CI) 4.4-20.4, p<0.0001), LAA flow velocity of <20 cm/s (OR 8.7, 95% CI 3.3-23.0, p = 0.0003) and a fibrinogen concentration of <377mg/dl (OR 3.2, 95% CI 1.5-6.9, p = 0.0201). The Lp(a) elevations and reduced LAA flow velocities are independently associated with thromboembolism in chronic NVAF.     

Assessment of the left atrial appendage mechanical function by three-dimensional echocardiography.

AIMS: We evaluated the feasibility of three-dimensional echocardiography, in the assessment of left atrial appendage (LAA) function. METHODS AND RESULTS: Forty-five patients underwent multiplane transoesophageal echocardiography. In addition to Doppler and two-dimensional echocardiography, data for three-dimensional echocardiography reconstruction were obtained during transoesophageal echocardiography. Left atrial appendage ejection fraction based on three-dimensional echocardiography volume measurements (EFv) and two-dimensional echocardiography area measurements (EFa), coupled with other echocardiographic data, were related to left atrial appendage late peak emptying velocity, a frequently used indicator of left atrial appendage function. Multiple regression analysis has revealed a significant association of peak emptying velocity with EFv (P<0.0001), spontaneous echocardiographic contrast (P=0.001), tricuspid regurgitation (P=0.03) and left ventricular hypertrophy (P=0.05). No significant relation was observed between peak emptying velocity and EFa, presence or absence of atrial fibrillation, left ventricular dysfunction, mitral stenosis and insufficiency, left atrial dilatation, pulmonary venous peak systolic, diastolic and peak reverse flow velocity at atrial contraction as well as left atrial appendage volumes derived from two-dimensional echocardiography and three-dimensional echocardiography. In a simple linear correlation, the degree of association between peak emptying velocity and EFv was higher as between peak emptying velocity and EFa (r=0.7 vs 0.4, both P<0.001). Observer variabilities for calculating EFv were considerably lower than for two-dimensional echocardiography derived EFa. Ejection fractions determined by two-dimensional echocardiography area measurements at 45 degrees, 90 degrees and 135 degrees cutplane angulations were related to EFv only at 135 degrees. CONCLUSIONS: Left atrial appendage ejection fraction calculation by three-dimensional echocardiography is feasible, more accurate than by two-dimensional echocardiography and has lower observer variability. Furthermore, an optimal cutplane angulation of the left atrial appendage view at 135 degrees has been demonstrated.     

Atrial myocardial deformation properties are temporarily reduced after cardioversion for atrial fibrillation and correlate well with left atrial appendage function.

AIM: This study was conducted to evaluate whether left atrial strain and strain rate correlate well with transesophageal parameters of stunning after atrial fibrillation. METHODS AND RESULTS: Twenty-two consecutive patients with chronic atrial fibrillation >/=3 months and <1 year were enrolled in the study. Transthoracic (TTE) and transesophageal (TEE) echocardiography with color Doppler myocardial imaging were performed before, 1 day after and 10 days after successful cardioversion. Left atrial transthoracic strain (S) and strain rate (SR) from lateral, inferior and anterior atrial walls, left atrial appendage tissue velocities, strain and strain rate values were measured with offline analysis. Left atrial appendage emptying (LAAEV) and filling (LAAFV) velocities were obtained from transesophageal echocardiography. Left atrial transthoracic, and left atrial appendage strain and strain rates were significantly lower following 1 day after cardioversion (TTE S/SR, 5.0 +/- 2.8%/2.3 +/- 1.0; TEE (septal) S/SR, 7.6 +/- 3.6%/1.6 +/- 0.7). There was a good correlation between these parameters and LAAEV (LA systolic strain and LAAEV, r = 0.73, P = 0.007). Left atrial and LAA strain and strain rate values improved over time, and correlated well with LAAEV, measured 10 days after cardioversion. CONCLUSIONS: Transthoracic atrial and TEE LAA strain and strain rate, which are quantitative measures of atrial function, are reduced after cardioversion, and recover subsequently. The good correlation between LAA function and TTE strain and strain rate suggests that TTE atrial parameters may help determine duration of anticoagulation.     

High-sensitivity C-reactive protein is predictive of successful cardioversion for atrial fibrillation and maintenance of sinus rhythm after conversion

BACKGROUNDS: Cardioversion for atrial fibrillation (AF) is the most effective treatment for the restoration of sinus rhythm (SR). Recently, an elevated level of hs-CRP has been shown to be associated with AF burden, suggesting that inflammation increases the propensity for persistence of AF. We examined whether the level of high-sensitivity C-reactive protein (hs-CRP) was predictive of the outcome of cardioversion for AF. METHODS AND RESULTS: One hundred and six patients with a history of symptomatic AF lasting > or =1 day (age 63+/-14 years, mean+/-S.D.) underwent cardioversion. Echocardiography and hs-CRP assay were performed immediately prior to cardioversion. SR was restored in 84 patients (79%). By using selected cutoff values, multiple discriminant analysis revealed significant associations between successful cardioversion and a shorter duration of AF (AF duration< or =36 days, odds ratio (OR), 0.98; 95% confidence interval (CI), 0.97-0.99), smaller left atrial diameter (left atrial diameter< or =40 mm, OR 0.82, 95% CI 0.71-0.94), better-preserved left ventricular ejection fraction (left ventricular ejection fraction> or =60%, OR 0.92, 95% CI 0.86-0.99), and lower hs-CRP level (hs-CRP< or =0.12 mg/dL, OR 0.33, 95% CI 0.21-0.51). During a follow-up period of 140+/-144 days, AF recurred in 64 patients (76%). By using a cutoff value of hs-CRP> or =0.06 mg/dL, Cox proportional-hazards regression model found that only hs-CRP level was an independent predictor of AF recurrence (OR 5.30, 95% CI 2.46-11.5) after adjustment for coexisting cardiovascular risks. When patients were divided by the hs-CRP level of 0.06 mg/dL, percentage of maintenance of SR below and above the cutoff was 53% and 4%, respectively (log-rank test, p<0.0001). CONCLUSIONS: hs-CRP level determined prior to cardioversion represents an independent predictor of both successful cardioversion for AF and the maintenance of SR after conversion.     

Right Atrial Thrombi and Depressed Right Atrial Appendage Function After Cardioversion of Atrial Fibrillation

BACKGROUND: It has been shown that cardioversion of atrial fibrillation may result in left atrial chamber and appendage dysfunction and cause new thrombi in the left atrium. The aim of this prospective study was to investigate right atrial appendage function and assess the incidence of new right atrial thrombi after electrical cardioversion. METHODS: Transthoracic echocardiography was performed in 25 patients 4 h before and at 24 h and 7 days after electrical cardioversion to determine right and left atrial mechanical function (internal atrial defibrillation, n = 16; external electrical cardioversion, n = 9), as assessed by peak A wave velocities derived from the transtricuspid and transmitral velocity profiles. In addition, transesophageal echocardiography was performed 4 h before and 24 h after cardioversion to evaluate postcardioversion thrombus formation in the right and left atrial chambers and to assess right and left atrial appendage function. The degree of spontaneous echo contrast was noted, and peak emptying velocities of the appendages were measured before and after cardioversion. RESULTS: Peak emptying velocities of both the right atrial appendage (mean +/- SD, 0.23 +/- 0.1 vs 0.32 +/- 0.11 m/sec; P = 0.02) and the left atrial appendage (0.3 +/- 0.15 vs 0.4 +/- 0.15 m/sec; P = 0.01) were significantly lower 24 h after cardioversion compared with 4 h before cardioversion, respectively. The degree of spontaneous echo contrast increased in the left atrium after cardioversion from 1.0 +/- 1.2 to 1.9 +/- 2.1 (P = 0.02), and in the right atrium, it increased from 0.8 +/- 1.1 to 1.2 +/- 1.1 (P = 0.1) after cardioversion. Peak A wave transtricuspid velocity increased from 0.26 +/- 0.05 m/sec at 24 h to 0.38 +/- 0.06 m/sec (P = 0.001) after 7 days; respective values for transmitral peak A wave velocity were 0.39 +/- 0.15 and 0.54 +/- 0.16 m/sec (P = 0.009). No thrombi were found in either the right or left atrium before cardioversion. In two patients, new thrombi in the right atrium were detected 24 h after internal atrial defibrillation. Thrombi were located at the superior rim of the fossa ovalis in both patients with patent foramen ovale. Another patient had developed a thrombus in the left atrial appendage. CONCLUSIONS: Electrical cardioversion may not only cause left atrial chamber and appendage dysfunction and left atrial thrombi but also lead to depressed right atrial appendage function and the generation of new thrombi in the body of the right atrium.