Clinical significance of perfusion imaging of the left atrial wall and structures in its cavity by contrast echocardiography.

This study examined whether myocardial contrast echocardiography (MCE) can visualize left atrial appendage myocardial perfusion using transesophageal echocardiography (TEE) with intracoronary injection of sonicated albumin. We also evaluated blood flow into normal structures (i.e. muscular trabeculae) and abnormal masses (i.e. fresh thrombi and myxomas) within the left atrium by MCE. TEE images were obtained with a biplane or multiplane 5 MHz transducer in 16 patients without significant coronary artery occlusive disease. Left atrial appendage myocardium was divided into 4 segments in both the transverse and longitudinal planes, and contrast opacification of each segment during MCE was visually evaluated by 2 independent observers. Visual assessment of contrast opacification of prominent muscular trabeculae within the left atrial appendage (6 patients), and of left atrial or left atrial appendage thrombi (4 patients), was also performed. The ratio of background-subtracted peak videointensity from muscular trabeculae or thrombi versus left atrial appendage myocardium was determined as corrected peak videointensity. In 3 patients with myxomas, contrast opacification of the tumor was visually assessed. Ninety-six segments of left atrial appendage myocardium were visually analyzed. Contrast opacification of the left atrial appendage myocardium was identified in 92 of 96 segments (96%, 95% confidence interval 0.90-0.98) by Observer 1 and in 91 of 96 segments (95%, 95% confidence interval 0.88-0.98) by Observer 2. MCE also enhanced the imaging of left atrial appendage muscular trabeculae, but not of left atrial or left atrial appendage thrombi. Corrected peak videointensity from thrombi was significantly lower than that from muscular trabeculae (0.15 +/- 0.11 vs 0.95 +/- 0.18, p < 0.05). All myxomas were distinctly opacified by MCE. Transesophageal MCE with intracoronary injection of sonicated albumin can image left atrial appendage myocardial perfusion. MCE allows the evaluation of blood flow into normal structures and abnormal masses within the left atrium.     

Observer Variation in the Echocardiographic Measurement of Maximum Atrial Septal Excursion: A Comparison of M‐Mode with Two‐Dimensional or Transesophageal Echocardiography

Background: Atrial septal aneurysm is typically diagnosed by transthoracic two‐dimensional or transesophageal echocardiography (2DE or TEE). Such techniques are highly dependent on visual inspection which predisposes to observer variation. This study compares inter‐ and intraobserver variations in the measurement of maximum atrial septal excursion (MASE) obtained using transthoracic M‐mode echocardiography (MME) with that obtained using 2DE or TEE. Methods: Consecutive patients with highly mobile atrial septal motion by visual inspection during 2DE or TEE were studied. MASE was estimated visually on 2DE or TEE. MME tracings were obtained with the cursor bisecting the parabola formed by the atrial septum at its maximum deviation from the midline. Electronic calipers were used to measure MASE for all echocardiographic techniques. Two observers provided two measurements each. Observer variation was determined by assessing standard deviation and confidence intervals of inter‐ and intraobserver differences. Results: Interobserver analysis showed standard deviations of 0.077 cm (95% CI 0.065–0.094) for MME and 0.280 cm (95% CI 0.242–0.334) for 2DE or TEE. Intraobserver analysis showed standard deviations of 0.08 cm (95% CI 0.068–0.101) for MME and 0.318 cm (95% CI 0.274–0.381) for 2DE or TEE. The mean magnitude of measured MASE was 0.44 cm higher with MME than with 2DE or TEE (95% CI 0.068–0.101). Conclusions: MME assessment of MASE is associated with substantially lower inter‐ and intraobserver variation than 2DE or TEE assessment. The magnitude of MASE is substantially higher with MME than with 2DE or TEE. (ECHOCARDIOGRAPHY, Volume **, ********)     

Diagnosis of noninfective cardiac mass lesions by two-dimensional echocardiography. Comparison of the transthoracic and transesophageal approaches

This study was conducted in 46 patients with cardiac thrombi, 15 patients with atrial myxomas, and 32 patients with other cardiac or paracardiac tumors. Diagnoses were subsequently proven by surgery, autopsy, computed tomography, magnetic resonance imaging, or angiography in all patients. All patients underwent precordial and transesophageal two-dimensional echocardiography to assess the various mass detection rates. Atrial myxomas and predominantly left-sided cardiac tumors were identified by both echocardiographic techniques with comparable detection rates. Left ventricular apical thrombi were detected more frequently by precordial echocardiography. In contrast, transesophageal echocardiography was superior in visualizing left atrial appendage thrombi, small and flat thrombi in the left atrial cavity, thrombi and tumors in the superior vena cava, and masses attached to the right heart and the descending thoracic aorta. These data indicate that transesophageal echocardiography leads to a clinically relevant improvement of the diagnostic potential in patients in whom cardiac masses are suspected or have to be excluded in order to ensure the safety of clinical procedures.     

Echocardiography in diagnostic assessment of peripheral arterial embolization

In an attempt to identify a cardiac source of emboli, two-dimensional echocardiography was performed postoperatively in 42 consecutive patients with acute peripheral arterial embolism requiring urgent embolectomy. The patients were divided into four groups. Group 1 included 14 patients with chronic atrial fibrillation, among whom four cases of intracavitary thrombi were detected. Group 2 included 13 patients with acute or previous myocardial infarction, and left ventricular thrombi were detected in three. Group 3 included one patient with a prosthetic mechanical aortic valve and one with mitral valve prolapse; thrombi were not detected in either. Group 4 comprised 13 patients with no clinical evidence of a cardiac source of embolism; in one of them a large left ventricular thrombus was detected. Altogether eight intracavitary thrombi were detected (19%), and only in three (7.1%) were the results of echocardiographic examinations defined as entirely normal. A number of clinically undetected cardiac lesions, such as mitral annular calcification and aortic valve calcification, possibly associated with peripheral arterial embolism, were also detected by postoperative echocardiography. Because of the high percentage of intracavitary thrombi detected and the therapeutic implications thereof, especially if embolism recurred, it is concluded that two-dimensional echocardiographic examination should be recommended for patients with acute peripheral embolism.     

Intra-atrial thrombolytic therapy for dissolution of chronic left atrial thrombi in patients undergoing balloon mitral commissurotomy.

The purpose of this study was to evaluate the solubility of left atrial thrombi to thrombolytics after failure of long-term anticoagulant therapy in patient with mitral stenosis. One hundred and eighty-one consecutive patients with mitral valve area < or = 1.5 cm(2) and without severe mitral regurgitation were screened with echocardiography; 30 were found to have left atrial thrombi. Follow-up echocardiography performed 7.4 +/- 5.6 months after warfarin therapy revealed that 8/30 of patients had complete dissolution and 3/30 had partial dissolution of the thrombi. Thirteen patients with residual isolated appendageal thrombi underwent balloon mitral commissurotomy and were randomized into four groups at the end of balloon mitral commissurotomy: group A, receiving intra-atrial infusion of heparin and tissue plasminogen activator (t-PA; n = 4); group B, heparin and streptokinase (n = 3); group C, heparin (n = 3); and group D, acting as control (n = 3). It was found that only two patients in the t-PA group had their thrombi either completely or partially dissolved within 48 hr. Thus, this study suggests that t-PA may have the potential of dissolving chronic left atrial thrombi.     

Efficacy of anticoagulation in resolving left atrial and left atrial appendage thrombi: A transesophageal echocardiographic study

BACKGROUND: Transesophageal echocardiography (TEE) is the gold standard for evaluation of the left atrium and the left atrial appendage (LAA) for the presence of thrombi. Anticoagulation is conventionally used for patients with atrial fibrillation to prevent embolization of atrial thrombi. The mechanism of benefit and effectiveness of thrombi resolution with anticoagulation is not well defined. METHODS AND RESULTS: We used a TEE database of 9058 consecutive studies performed between January 1996 and November 1998 to identify all patients with thrombi reported in the left atrium and/or LAA. One hundred seventy-four patients with thrombi in the left atrial cavity (LAC) and LAA were identified (1.9% of transesophageal studies performed). The incidence of LAA thrombi was 6.6 times higher than LAC thrombi (151 vs 23, respectively). Almost all LAC thrombi were visualized on transthoracic echocardiography (90.5%). Mitral valve pathology was associated with LAC location of thrombi (P <.0001), whereas atrial fibrillation or flutter was present in most patients with LAA location of thrombi. Anticoagulation of 47 +/- 18 days was associated with thrombus resolution in 80.1% of the patients on follow-up TEE. Further anticoagulation resulted in limited additional benefit. CONCLUSIONS: LAC thrombi are rare and are usually associated with mitral valve pathology. Transthoracic echocardiography is effective in identifying these thrombi. LAA thrombi occur predominantly in patients with atrial fibrillation or flutter. Short-term anticoagulation achieves a high rate of resolution of LAA and LAC thrombi but does not obviate the need for follow-up TEE.     

Left atrial thrombus. Its evolution with oral anticoagulation]

Left ventricular thrombi were found in 25 patients by two-dimensional echocardiography. All patients were in atrial fibrillation, 16 had mitral or mitroaortic valve diseases and nine mitral or mitroaortic bioprosthetic valves. Nine patients (36%) had history of arterial embolism. At diagnostic time, oral anticoagulation with coumadin was instaured in all the patients. Periodic clinic and echocardiography follow-up was performed. Left atrial thrombi either disappeared (18 patients [72%]) or reduced their size (one patient). Six patients with mitral stenosis were considered as candidates to percutaneous mitral valvuloplasty, which was performed in 4 patients whose thrombi disappeared with anticoagulation therapy in 6 months. During the follow-up one patient had cerebral embolism without sequelae. Conclusions: 1st. Patients with left atrial thrombi have high risk for arterial embolism. 2nd. Left atrial thrombi disappear in a high proportion after prescribing oral anticoagulation, which has some important therapeutic implications.     

三维超声评价重度妊娠高血压综合征患者分娩前后左室功能的初步研究

目的探讨实时三维超声（RT-3DE）成像技术定量测定重度妊娠高血压综合征（简称妊高征）患者分娩前后的左室功能（EF）的临床价值。方法选择50例重度妊高征患者（P组）和50例正常妊娠者（N组）,分别采用RT-3DE技术和M型超声（MME）测定分娩前左室功能和分娩后1个月左室功能。结果孕妇分娩前,RT-3DE和MME技术所测P组和N组患者左心功能差异有统计学意义（P〈0.05）;MME技术所测妊高征患者左心功能分娩前后差异无统计学意义（P〉0.05）,而RT-3DE技术测定结果显示差异有统计学意义（P〈0.05）。结论 RT-3DE成像技术,可快捷、准确的测定重度妊高征患者左室功能的变化情况,可应用于临床工作中。     

Transesophageal Echocardiography for the Prevention of Embolic Complications After Catheter Ablation for Atrial Fibrillation

Background: Thromboembolic complications during left-sided ablations range between 1.5 and 5.4%. Preprocedural TEE has been used to exclude the presence of left atrial thrombi in order to minimize risk. The use of TEE is empiric and it has not been evaluated in contemporary practice.
Methods and Results: A multicenter national survey describing the practice at 11 Canadian teaching hospitals. A total of 2,225 patients underwent elective catheter ablation for symptomatic AF. Transesophageal echocardiography (TEE) was used either routinely or selectively as a preablative strategy in patients. There were 996 patients in a routine preprocedure TEE strategy and 1,190 in a selected TEE strategy; 1 center (n = 39 patients) did not perform TEE. Twelve of 996 (1.2%) in the routine unselected cohort had thrombi identified. TEEs were performed in 200 of 1,190 in the selected cohort; 4 (2.0%) left atrial thrombi were observed; there was no significant difference in the prevalence of thrombi (P = 0.34). A total of 11 embolic events occurred inclusive of all groups. There was no difference in event rates between the 2 strategies (0.6% and 0.4%, P = 0.54). Events were unrelated to AF duration (persistent vs paroxysmal, r = 0.03, N = 2,225, P = 0.9).
Conclusion: The selection criteria employed to perform TEEs did not increase the chance of identifying LA thrombi in a patient cohort with primarily nondilated left atria and paroxysmal AF. The overall thromboembolic event rate was low (0.49%) and was not significantly different between the 2 TEE strategies.     

Location, size and morphological characteristics of left atrial thrombi as assessed by echocardiography in patients with rheumatic mitral valve disease.

AIMS: This study aimed to assess the use of transthoracic and transoesophageal echocardiography in diagnosing the thrombi located in the left atrium and/or left atrial appendage in patients with rheumatic mitral valve disease, and to investigate the characteristics of thrombi in comparison to intraoperative findings. METHODS AND RESULTS: The study group was comprised of 474 patients who underwent transthoracic and transoesophageal echocardiography prior to mitral valve surgery. Location, thickness and morphological characteristics of thrombi were determined by transoesophageal echocardiography. Intraoperative assessment disclosed left atrial thrombi in 105 patients. Thickness of thrombi < or = 1cm, and thrombi confined to left atrial appendage were associated with false-negative results by transthoracic echocardiography. However, diameter and morphological characteristics of thrombi, left atrial and left atrial appendage size, and the presence of the spontaneous echo contrast were not associated with the diagnosis of thrombi by transthoracic echocardiography. For overall left atrial thrombi, sensitivity and specificity of transthoracic echocardiography were 32%, and 94%, respectively. Sensitivity and specificity of transoesophageal echocardiography for thrombi in the left atrial appendage were 98%, and 98%, for thrombi in the main left atrial cavity were 81%, and 99%, and for thrombi located in both left atrium and appendage cavities were 100%, and 100%, respectively. CONCLUSION: In patients with rheumatic mitral valve disease, detection of left atrial thrombi by transthoracic echocardiography seems to be determined by thickness and location of thrombi. The multilobed structure of the left atrial appendage and artifacts over posterior wall of the left atrium may still prevent precise diagnosis even with transoesophageal echocardiography.     

In vivo magnetic resonance imaging and surgical histopathology of intracardiac masses: distinct features of subacute thrombi

We evaluated intracardiac masses in vivo, in situ and histologically to determine tissue properties revealed by magnetic resonance (MR) imaging. In 15 consecutive patients scheduled for cardiotomy, the cardiac chambers were studied preoperatively with MR imaging and echocardiography. Visual examination of one or more chambers was performed during cardiotomy for mitral valve replacement, aneurysmectomy, atrial septal repair and atriotomy. Six thrombi (1 atrial appendage, 5 ventricular) and 2 atrial myxomas were removed and subjected to histological analysis. All masses were detected preoperatively by MR imaging. The smallest was a subacute 3-mm mural clot in the left ventricle and was undetected by transesophageal and transthoracic echocardiography. The 3 subacute clots had homogeneously low MR signals, did not enhance with gadolinium and exhibited magnetic susceptibility effects; histopathology confirmed these clots to be avascular and laden with dense iron deposition related to hemoglobin breakdown products. The 3 organized clots had intermediate and heterogeneous MR signals and multiple areas of gadolinium enhancement. The 2 myxomas had low MR signals and gadolinium enhancement in the core and septal attachment; these areas had dense neovascular channels. Subacute thrombi appear to have MR features that are distinct from organized thrombi and myxomas, and MR images of subacute thrombi contrast sharply with normal cardiac structures, enabling detection of thin mural clots that may be echographically occult. These findings may be of value, because a subacute clot may be more likely than an organized thrombus to give rise to an embolus.     

Cardiological diagnosis in arterial embolism]

Potential cardiac sources of arterial embolism are in particular thrombi within the left atrium or ventricle, or attached to a prosthetic valve, intracardiac tumors, and vegetations due to endocarditis. Patent foramen ovale and atrial septal defect may lead to paradoxical embolism, and spontaneous echo contrast within the heart has to be considered as a parameter of increased thromboembolic risk. In rare cases, atrial septal aneurysm, mitral valve prolapse or annulus calcification and calcified aortic stenosis has to be taken into consideration. Current method of choice for diagnosis of these abnormalities is echocardiography. When the transthoracic approach fails, transesophageal echocardiography (TEE) leads to a definite diagnosis in most cases. Precordial echocardiography allows the detection of left ventricular thrombi with a sensitivity ranging between 72 and 95%, and monoplane TEE does usually not increase these numbers. In contrast, thrombi within the left atrium and particularly in the left atrial appendage can be detected with a significantly higher detection rate when TEE is used. The same is true for spontaneous echo contrast in the left atrium, a phenomenon which is almost exclusively diagnosed by TEE, as well as for endocarditis associated vegetations that can be identified by TEE with a sensitivity higher than 90%. Patient foramen ovale is usually diagnosed by precordial contrast echocardiography combined with a Valsalva maneuver; color Doppler or contrast TEE allows to increase the detection rate. In the diagnosis of prosthetic valve attached thrombi and vegetations, TEE is clearly superior compared to the precordial examination, at least concerning prosthetic devices in mitral position. If echocardiography fails to identify a potential cardiac source of embolism, other techniques don't add significant information in most cases. Detection of a potential source of embolism, however, does not necessarily prove that the particular finding represents the true etiology of an embolic event; results of all clinical and technical examinations have to be evaluated in a critical synopsis. In addition, proper therapeutic consequences in quite a number of abnormalities considered as potential cardiac sources of embolism are not yet defined.     

Use of echocardiography in detecting cardiac sources of embolus

Up to 20% of all ischemic strokes are felt to be the result of emboli from the heart. High resolution transthoracic (TTE) and transesophageal (TEE) echocardiography have been the principal diagnostic tools for detecting associated cardiac abnormalities and for guiding medical and surgical approaches to these patients. In addition to identifying the precise location and morphological characteristics of intracardiac masses, echocardiography has improved our ability to predict embolic potential of these masses. Specific cardiac lesions that are predisposed to stroke and are readily identifiable by echocardiography include: cardiac thrombi, valvular vegetations, cardiac tumors, aortic atheroma, atrial septal aneurysm, and regional left ventricular wall abnormalities. Careful interrogation of patients with cerebrovascular accidents has identified a potential cardiac source of embolus in approximately 30%. This is largely due to the advent of TEE, which has provided much better assessment of posterior cardiac chambers including left atrium and left atrial appendage. Use of TEE in identifying a cardiac source of embolus is indicated in patients with stroke who are young, have no apparent cerebrovascular disease, or have recurrent embolic events. Echocardiography is an essential diagnostic tool in evaluating patients with a suspected cardiac source of embolus. TTE and TEE provide invaluable information regarding the majority of cardiac sources of embolus.     

The increasing role of transesophageal echocardiography in unexplained cerebral ischemia

Cerebrovascular disease is a leading cause of morbidity and mortality in the United States. A significant number of cerebral infarctions are due to a cardiac source of embolus. Transesophageal echocardiography (TEE) is being used with increasing frequency to study patients with potential cardiac causes of cerebral ischemia. TEE has a higher sensitivity for detecting left atrial and left atrial appendage thrombi and for visualizing abnormalities of the atrial septum such as patent foramen ovale and aneurysm. Abnormalities of the aorta and native and prosthetic valves can now be clearly identified by TEE. Preliminary data suggest that TEE may influence clinical management in patients with unexplained stroke.     

Detection of left atrial auricular thrombus in patients with atrial fibrillation and risk factors of thromboembolic complications: the role of transesophageal echocardiography and multispiral computer tomography

Transesophageal echocardiography (TEE) is routinely used for visualization of left auricular thrombi in patients with atrial fibrillation (AF). Multispiral computed tomography (MSCT) with the use of contrast preparations is a novel method of visualization of intracardiac structures. Forty three patients (27 men, 16 women aged 46 - 81 years) with duration of atrial fibrillation > 48 hours and scheduled for sinus rhytm restoration were included in this study. TEE and MSCT were carried out in all patients during first 3 days of hospitalization. If according to both methods there were no thrombi in the left auricle cardioversion was performed. If data of one of the methods were suspicious of left auricular thrombus cardioversion was not performed. In these patients both investigations were repeated after 8 weeks of therapy with warfarin. If initially detected mass decreased or disappeared at the background of indirect anticoagulants, it was considered to be a thrombus. In 1/3 of patients repeat examination allowed to reject initial diagnosis of left auricular thrombosis. Simultaneous application of TEE and MSCT detected more thrombi than the use of either of these methods. Rate of detection of thrombi in left atrial auricle with the use of both methods was 32%.     

Usefulness of transesophageal echocardiography for the detection of left atrial thrombi in patients with rheumatic heart disease

Transesophageal (TEE) and transthoracic (TTE) echocardiograms were performed in 110 patients with rheumatic heart disease to evaluate the usefulness of these methods for the detection of left atrial thrombi. TEE was better than TTE for detecting left atrial thrombi (21 vs 9). The thrombi not detected by TTE were in the left atrial appendage in ten and over the left atrial posterior wall in two. Patients with left atrial thrombi had significantly smaller mitral valve area (P less than 0.01) and greater left atrial dimension (P less than 0.05) than those without. All patients with left atrial thrombi had atrial fibrillation. Thirty-one patients underwent surgical intervention and 13 were found to have left atrial thrombi. TEE detected left atrial thrombi in all 13 patients with a sensitivity of 100%, specificity of 100%, and accuracy of 100%, while TTE detected left atrial thrombi in only nine of these 13 patients with a sensitivity of 69.2%, specificity of 100%, and accuracy of 87.1%. Thus, TEE is superior to TTE for the detection of left atrial thrombi, especially for those thrombi located in the left atrial appendage and along the left atrial posterior wall.     

Intracardiac thrombi in primary antiphospholipid syndrome: two case reports

We describe two patients who developed stroke and ischemia of the left lower limb, related to intracardiac thrombi, as the first manifestation of primary antiphospholipid syndrome (PAPS). Transesophageal echocardiography (TEE) revealed intracardiac thrombi as abnormal hyperechogenic, nonmobile masses, firmly attached to the left atrial appendage and the anterior part of the mitral annulus, respectively. Our patients received high-intensity oral anticoagulant therapy (INR 3.0–4.0), which resulted in the rapid disappearance of clinical symptoms, without subsequent recurrence of thromboembolic manifestations, and the disappearance of intracardiac thrombi on TEE. Our findings underscore that PAPS should be suspected in patients presenting with intracardiac thrombi, even if they have no previous history of thromboembolic disorders. Moreover, because intracardiac thrombi may precede other manifestations of PAPS, this finding in young patients without underlying heart disease should invoke a search for both antiphospholipid and anticardiolipin antibodies.     

Dynamic intracavitary echoes studied by transthoracic and transesophageal echocardiography]

One hundred consecutive echocardiograms performed on adults using transthoracic and transesophageal (TEE) transducers were analyzed in order to determine the prevalence of spontaneous contrast (SC) and the factors associated with it. Indications for study included complex congenital cardiopathy, evaluation of valve lesions or prosthetic valves, dissecting aortic aneurysm, cardiac masses and evaluation of ventricular function. SC was observed only with TEE and appeared in 25% of cases, most frequently in left atrium. Factors associated with contrast included mitral valve disease and replacement, ventricular dysfunction, left atrial dilatation and atrial fibrillation. An important relationship existed between SC and presence of thrombi. Atrioventricular valvular regurgitation was not associated with SC. Results are compared with those of previous series.     

Underestimation of prosthetic mitral valve areas: role of transseptal catheterization in avoiding unnecessary repeat mitral valve surgery

In patients with symptoms of heart failure after mitral valve replacement, identification of a stenosed prosthesis may be difficult. Twelve such patients were evaluated, presenting at a mean of 8.4 years after mitral valve replacement (four mechanical, eight porcine). Transvalvular pressure gradients were obtained using both indirect (pulmonary capillary wedge) and direct (transseptal catheterization) measurements of left atrial pressure. In all 12 patients, the diastolic gradient across the prosthetic valve was overestimated when pulmonary wedge rather than transseptal measurements were used. Calculated mitral valve prosthetic area was underestimated by the pulmonary wedge determinations. These findings may be caused by either the phase delay of the pulmonary wedge V wave relative to the transseptal V wave, resulting in a higher diastolic mean left atrial pressure, or the faulty wedge determinations in the setting of pulmonary hypertension, or both. In patients being considered for repeat mitral valve replacement because of prosthetic valve stenosis, transseptal catheterization allows for more accurate determination of prosthetic valve area and more accurately defines the need for repeat mitral valve surgery.     

Early heparinization decreases the incidence of left atrial thrombi detected by intracardiac echocardiography during radiofrequency ablation for atrial fibrillation

INTRODUCTION: We reviewed our experience in managing intracardiac ultrasound-detected left atrial thrombus and analyzed the impact of the timing of heparin therapy on thrombus incidence. METHODS AND RESULTS: We identified 508 patients undergoing ablation procedures for atrial fibrillation in which intracardiac ultrasound was used. All patients received unfractionated heparin during the procedure: 31 patients before the first transseptal puncture (preTS1), 257 between the first and second transseptal punctures (TS1-TS2), and 220 following both punctures (postTS2). By using intracardiac echocardiography (ICE), thrombus was detected in 30 of these 508 patients (5.9%). Of these, 29 were in the left atrium and constituted our study group. In 21 patients, the thrombi were successfully aspirated from the left atrium using strong suction through the transseptal sheath. All patients in whom thrombi were aspirated did well without neurological event or death. When patients received heparin therapy either preTS1 or TS1-TS2, there was a significant decrease in the occurrence of ICE-detected left atrial thrombus compared with those who received heparin postTS2 (0 of 31 patients (0%) preTS, 9 of 257 (3.5%) TS1-TS2, and 20 of 220 (9.1%) postTS2; (preTS1 vs postTS2, p = 0.01; preTS2 [preTS1 and TS1-TS2] vs postTS2, p < 0.001). CONCLUSION: Early administration of intravenous heparin, specifically before transseptal puncture, decreases the incidence of left atrial thrombi.