Does mitral regurgitation reduce the risks of thrombosis in atrial fibrillation and flutter?

AIMS: Blood stasis is the main cause of left atrial thrombosis (LAT) in atrial tachyarrhythmias. The high-velocity flow inside the left atrium, due to mitral valve regurgitation, may prevent clot formation but the topic has never been investigated in large-scale studies. The aim of our study was to evaluate whether the presence and degree of mitral regurgitation have a protective role against LAT risk. METHODS: A total of 1302 consecutive adult patients with paroxysmal or persistent atrial fibrillation or flutter undergoing cardioversion, submitted to transesophageal echocardiography, were retrospectively enrolled in the study. The study population was divided into three groups according to the mitral regurgitation degree: absent, mild-to-moderate and severe. RESULTS: Among 1302 patients enrolled in the study, patients without mitral regurgitation were 248 (19%), those with mild-to-moderate 970 (75%), whereas 84 had severe mitral regurgitation (6%). LAT incidence was significantly lower in patients with severe mitral regurgitation compared with those with mild-to-moderate (mitral regurgitation) (2.4 vs. 8.9%, P < 0.05), and similar to subjects without mitral regurgitation (2.4%). CONCLUSION: Despite patients with severe regurgitation having clinical and echo characteristics predisposing to LAT (higher age, heart failure, higher atrial size, lower ventricular function) thrombosis prevalence was significantly lower than for those with mild-to-moderate mitral regurgitation. The percentage of LAT in severe mitral regurgitation cases was very low and similar to that of cases without regurgitation which were characterized by lower age, normal left ventricular function or other risk factors, reinforcing the hypothesis of a protecting role against atrial thrombosis of mitral regurgitation.

Real-time three-dimensional transoesophageal echocardiography: a new intraoperative feasible and useful technology in cardiac surgery.

A new generation of transoesophageal echocardiographic probes with a novel matrix array technique has been recently introduced, allowing three-dimensional (3D) presentation of cardiac structures in real-time. This new tool may potentially provide fast and complete 3D information about cardiac structures improving spatial orientation and overcoming limitations of offline 3D technologies. The aim of this study was to demonstrate the feasibility and usefulness of real-time 3D transoesophageal echocardiography (TOE) for the intraoperative evaluation of cardiac surgery procedures. One-hundred patients underwent transoesophageal echocardiographic examination during cardiac surgery as a part of their routine clinical practice. In the intraoperative pre- and post-cardiopulmonary bypass periods complete 2D and 3D transoesophageal examinations were performed. Feasibility and duration of examinations, and immediate additional anatomical value of 3D versus 2D-TOE were annotated intraoperatively. Image quality, additional clinical value of 3D- compared to standard 2D-TOE and the accuracy in the description of mitral valve pathology by a surgeon and an echocardiographer were evaluated off-line. No complications related to transoesophageal examination occurred and successful intubation was achieved in all 100 patients. Therefore, 200 examinations were performed and analysed considering the pre- and post-cardiopulmonary bypass periods. The mean number of acquisitions per patient was 16 +/- 14, including 3D real-time, zoom, full-volume and colour full volume modalities. The duration of the 3D examination was 16 +/- 10 min and the mean image quality score 2.8 +/- 0.7 (in a scale 1-4). In 36 out of 100 cases (36%) 3D-TOE provided additional anatomical information. The surgeon evaluated 3D images easier and more accurately than 2D images (88% vs. 76% in the evaluation of mitral valve scallop). Real-time 3D TOE may be used routinely for the intraoperative evaluation of cardiac surgery. Imaging with this new probe facilitates intraoperative evaluation of several surgical procedures with an additional clinical value in selected cases.

Incidence of spontaneous echocontrast, 'sludge' and thrombi before cardioversion in patients with atrial fibrillation: new insights into the role of transesophageal echocardiography.

OBJECTIVES: Transesophageal echocardiography (TEE)-guided cardioversion has been demonstrated to be well tolerated in patients with atrial fibrillation. Guidelines do not suggest whether patients with severe spontaneous echocontrast (SEC) and sludge can be safely submitted to cardioversion. In our observational study, we analyzed the prevalence of SEC in patients with atrial fibrillation taking different anticoagulant therapies, the incidence of embolic complications after cardioversion in patients with severe SEC or sludge and the usefulness of TEE in reducing embolic complications in these patients. METHODS: The study population consisted of 1104 patients with atrial fibrillation, candidates for cardioversion and submitted to TEE. They were divided into four groups: effective conventional oral anticoagulation, short-term anticoagulation, subtherapeutic anticoagulation and effective oral anticoagulation for less than 3 weeks for different clinical reasons. Cardioversion was postponed in patients with atrial thrombosis; in the presence of severe SEC, the decision to cardiovert was left to the treating physician. RESULTS: Atrial thrombosis was detected in 65 (5.9%) patients, and SEC was detected in the majority of patients independent of the anticoagulant scheme; in 131 patients, it was severe and, in this group, sludge was identified in 57 patients. Cardioversion was performed in 922 patients and was successful in 849 (including 22 patients with severe SEC and four with sludge) with one minor embolic event. CONCLUSION: SEC and sludge are frequently observed in patients with atrial fibrillation undergoing cardioversion. A TEE approach may prevent the risk of embolic events. In the presence of severe SEC and sludge, treating physicians frequently postpone cardioversion, even though in the patients submitted to cardioversion, no events were observed.

Image integration-guided catheter ablation of atrial fibrillation: a prospective randomized study.

BACKGROUND: Several studies have provided details of left atrial anatomy by means of the image integration techniques, particularly focusing on the atypical patterns of the pulmonary veins. OBJECTIVE: To compare, in a prospective, randomized fashion, the conventional method of pulmonary vein disconnection and the image integration-guided approach. METHODS: Two hundred and ninety consecutive patients (290 patients, mean age 55 +/- 11 years) with drug-refractory paroxysmal or persistent atrial fibrillation were enrolled in the study and were divided into two treatment groups: group 1 (145 patients) undergoing an imaging integration-guided (CartoMerge TM) ablation; group 2 (145 patients) treated by a conventional radiofrequency catheter ablation procedure. The arrhythmia was refractory to at least two antiarrhythmic drugs (IC, amiodarone). RESULTS: Electrical disconnection of all identified pulmonary veins was obtained in all patients of both groups. Bidirectional block of the cavotricuspid isthmus was achieved in 34 group 1 patients and in 40 group 2 patients. Left mitral isthmus ablation was attempted in 52 group 1 patients and in 56 group 2 patients. At a mean follow-up of 14 +/- 12 months, the atrial fibrillation-free survival rate was significantly higher in group 1 patients compared with group 2 patients (88% vs 69%, P = 0.017). The analysis for the subset of patients with previously ineffective ablation (98 patients: 52 group 1 patients and 46 group 2 patients) showed a significantly lower recurrence rate in group 1 versus group 2 (19% vs 48%, P < 0.01). CONCLUSIONS: Our data indicate a superior efficacy of the image-integration guided catheter ablation of atrial fibrillation over the long term.