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Thromb Haemost 2016; 115(03): 663-677
DOI: 10.1160/th15-07-0532
Stroke, Systemic or Venous Thromboembolism
Schattauer GmbH

Prevalence of left atrial thrombus in patients with non-valvular atrial fibrillation

A systematic review and meta-analysis of the literature
Matteo Nicola Dario Di Minno
1   Unit of cell and molecular biology in cardiovascular diseases, Centro Cardiologico Monzino, IRCCS, Milan, Italy
,
Pasquale Ambrosino
2   Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy
,
Antonio Dello Russo
3   Cardiac Arrhythmia Research Center, Centro Cardiologico Monzino, IRCCS, Milan, Italy
,
Michela Casella
3   Cardiac Arrhythmia Research Center, Centro Cardiologico Monzino, IRCCS, Milan, Italy
,
Elena Tremoli
1   Unit of cell and molecular biology in cardiovascular diseases, Centro Cardiologico Monzino, IRCCS, Milan, Italy
,
Claudio Tondo
3   Cardiac Arrhythmia Research Center, Centro Cardiologico Monzino, IRCCS, Milan, Italy
› Author Affiliations
Further Information

Publication History

Received: 06 July 2015

Accepted after major revision: 22 October 2015

Publication Date:
20 March 2018 (online)

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Summary

We performed a meta-analysis about the prevalence of left atrial thrombus (LAT) in patients with atrial fibrillation (AF) undergoing trans-esophageal echocardiography (TEE). Studies reporting on LAT presence in AF patients were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases and the pooled LAT prevalence was evaluated as weighted mean prevalence (WMP). Seventy-two studies (20,516 AF patients) showed a LAT WMP of 9.8 % (95 %CI: 7.6 %-12.5 %). LAT presence was associated with a higher age (mean difference: 2.56, 95 %CI: 1.49–3.62), and higher prevalence of female gender (OR: 1.35, 95 %CI: 1.04–1.75), hypertension (OR: 1.78, 95 %CI: 1.38–2.30), diabetes mellitus (OR: 1.86, 95 %CI: 1.33–2.59) and chronic heart failure (OR: 3.67, 95 %CI: 2.40–5.60). Overall, LAT patients exhibited a higher CHADS2-score (mean difference 0.88, 95 %CI: 0.68–1.07) and a higher risk of stroke/systemic embolism (OR: 3.53, 95 %CI: 2.24–5.56) compared with those without LAT. A meta-regression showed an inverse association between LAT prevalence and the presence of anticoagulation (Z-value: −7.3, p< 0.001). Indeed, studies in which 100 % of patients received oral anticoagulation reported a 3.4 % WMP of LAT (95 %CI: 1.3 %–8.7 %), whereas studies in which 0 % of patients received anticoagulation showed a LAT WMP of 7.4 % (95 %CI: 2.3 %–21.5%). Our data suggest that LAT is present in ≈10 % of AF patients, and is associated with a 3.5-fold increased risk of stroke/systemic embolism. Interestingly, LAT is also reported in some of patients receiving anticoagulation. The implementation of the screening of LAT in AF patients before cardioversion/ablation could be useful for the prevention of vascular events.

Keywords

Atrial fibrillation - left atrial thrombus - transesophageal echocardiography

Supplementary Material

 

  • References

  • 1 Zoni-Berisso M. et al. Frequency, patient characteristics, treatment strategies, and resource usage of atrial fibrillation (from the Italian Survey of Atrial Fibrillation Management (ISAF) study). Am J Cardiol 2013; 111: 705-711.
    CrossrefPubMedGoogle Scholar
  • 2 Wann LS. et al. 2011 ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (update on dabigatran): a report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. J Am Coll Cardiol 2011; 57: 1330-1337.
    CrossrefPubMedGoogle Scholar
  • 3 Calkins H. et al. 2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design: a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation. Developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology (ESC) and the European Cardiac Arrhythmia Society (ECAS); and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). Endorsed by the governing bodies of the American College of Cardiology Foundation, the American Heart Association, the European Cardiac Arrhythmia Society, the European Heart Rhythm Association, the Society of Thoracic Surgeons, the Asia Pacific Heart Rhythm Society, and the Heart Rhythm Society. Heart Rhythm 2012; 9: 632-696.e21.
    CrossrefPubMedGoogle Scholar
  • 4 Scherr D. et al. Incidence and predictors of periprocedural cerebrovascular accident in patients undergoing catheter ablation of atrial fibrillation. J Cardiovasc Electrophysiol 2009; 20: 1357-1363.
    CrossrefPubMedGoogle Scholar
  • 5 Lown B. et al. “Cardioversion” of atrial fibrillation: a report on the treatment of 65 episodes in 50 patients. N Engl J Med 1963; 269: 325-331.
    CrossrefPubMedGoogle Scholar
  • 6 Jensen JB, Humphries JO, Kouwenhoven WB. et al. Electroshock for atrial flutter and atrial fibrillation: follow-up studies on 50 patients. J Am Med Assoc 1965; 194: 1181-1184.
    CrossrefPubMedGoogle Scholar
  • 7 Vazquez SR. et al. Peri-procedural anticoagulation in patients undergoing ablation for atrial fibrillation. Thromb Res 2010; 126: e69-77.
    CrossrefPubMedGoogle Scholar
  • 8 Fuster V. et al. ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Circulation 2006; 114: e257-354.
    CrossrefPubMedGoogle Scholar
  • 9 Chimowitz MI. et al. Left atrial spontaneous echo contrast is highly associated with previous stroke in patients with atrial fibrillation or mitral stenosis. Stroke 1993; 24: 1015-1019.
    CrossrefPubMedGoogle Scholar
  • 10 Camm AJ. et al. 2012 focused update of the ESC Guidelines for the management of atrial fibrillation: an update of the 2010 ESC Guidelines for the management of atrial fibrillation. Developed with the special contribution of the European Heart Rhythm Association. Eur Heart J 2012; 33: 2719-2747.
    CrossrefPubMedGoogle Scholar
  • 11 January CT. et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/ American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2014; 64: e1-76.
    CrossrefPubMedGoogle Scholar
  • 12 Atrial Fibrillation Investigators. Risk factors for stroke and efficacy of anti-thrombotic therapy in atrial fibrillation. Analysis of pooled data from five randomized controlled trials. Arch Intern Med 1994; 154: 1449-1457.
    CrossrefPubMedGoogle Scholar
  • 13 Scherr D. et al. Incidence and predictors of left atrial thrombus prior to catheter ablation of atrial fibrillation. J Cardiovasc Electrophysiol 2009; 20: 379-384.
    CrossrefPubMedGoogle Scholar
  • 14 Moher D. et al. Preferred reporting items for systematic reviews and meta-ana-lyses: the PRISMA statement. PLOS Medicine 2009; 6: e1000097.
    CrossrefPubMedGoogle Scholar
  • 15 Juni P. et al. The hazards of scoring the quality of clinical trials for meta-analysis. J Am Med Assoc 1999; 282: 1054-1060.
    CrossrefPubMedGoogle Scholar
  • 16 Higgins JP. et al. Measuring inconsistency in meta-analyses. Br Med J 2003; 327: 557-560.
    CrossrefPubMedGoogle Scholar
  • 17 Sterne JA. et al. Systematic reviews in health care: investigating and dealing with publication and other biases in meta-analysis. Br Med J 2001; 323: 101-105.
    CrossrefPubMedGoogle Scholar
  • 18 Duval S, Tweedie R. Trim and fill: A simple funnel-plot-based method of testing and adjusting for publication bias in meta-analysis. Biometrics 2000; 56: 455-463.
    CrossrefPubMedGoogle Scholar
  • 19 Abe Y. et al. Prediction of embolism in atrial fibrillation: classification of left atrial thrombi by transesophageal echocardiography. Jpn Circ J 2000; 64: 411-415.
    CrossrefPubMedGoogle Scholar
  • 20 Abe Y. et al. Embolic attack in patients with atrial fibrillation and atrial thrombus depends on the character of the thrombus. Circ J 2003; 67: 203-208.
    CrossrefPubMedGoogle Scholar
  • 21 Achenbach S. et al. Electron beam computed tomography for the detection of left atrial thrombi in patients with atrial fibrillation. Heart 2004; 90: 1477-1478.
    CrossrefPubMedGoogle Scholar
  • 22 Akoum N. et al. Association of atrial fibrosis quantified using LGE-MRI with at-rial appendage thrombus and spontaneous contrast on transesophageal echoc-ardiography in patients with atrial fibrillation. J Cardiovasc Electrophysiol 2013; 24: 1104-1109.
    PubMedGoogle Scholar
  • 23 Archer SL. et al. Role of transesophageal echocardiography in the detection of left atrial thrombus in patients with chronic nonrheumatic atrial fibrillation. Am Heart J 1995; 130: 287-295.
    CrossrefPubMedGoogle Scholar
  • 24 Bollmann A. et al. Atrial fibrillatory rate and risk of left atrial thrombus in atrial fibrillation. Europace 2007; 9: 621-626.
    CrossrefPubMedGoogle Scholar
  • 25 Boyd AC. et al. Left ventricular mass predicts left atrial appendage thrombus in persistent atrial fibrillation. Eur Heart J Cardiovasc Imaging 2013; 14: 269-275.
    CrossrefPubMedGoogle Scholar
  • 26 Bozdemir V. et al. The association of beta-fibrinogen 455 G/A gene polymorphism with left atrial thrombus and severe spontaneous echo contrast in atrial fibrillation. Anadolu Kardiyol Derg 2010; 10: 209-215.
    CrossrefPubMedGoogle Scholar
  • 27 Brown J, Sadler DB. Left atrial thrombi in non-rheumatic atrial fibrillation: assessment of prevalence by transesophageal echocardiography. Int J Card Imaging 1993; 9: 65-72.
    CrossrefPubMedGoogle Scholar
  • 28 Choi BH. et al. Detection of left atrial thrombus in patients with mitral stenosis and atrial fibrillation: retrospective comparison of two-phase computed tomography, transoesophageal echocardiography and surgical findings. Eur Radiol 2013; 23: 2944-2953.
    CrossrefPubMedGoogle Scholar
  • 29 Corrado G. et al. Atrial thrombi resolution after prolonged anticoagulation in patients with atrial fibrillation. Chest 1999; 115: 140-143.
    CrossrefPubMedGoogle Scholar
  • 30 Corrado G. et al. Prevalence of atrial thrombi in patients with atrial fibrillation/ flutter and subtherapeutic anticoagulation prior to cardioversion. Eur J Echoc-ardiogr 2004; 5: 257-261.
    CrossrefPubMedGoogle Scholar
  • 31 Cresti A. et al. Frequency and significance of right atrial appendage thrombi in patients with persistent atrial fibrillation or atrial flutter. J Am Soc Echocardiogr 2014; 27: 1200-1207.
    CrossrefPubMedGoogle Scholar
  • 32 Dawn B. et al. Cardiovascular death in patients with atrial fibrillation is better predicted by left atrial thrombus and spontaneous echocardiographic contrast as compared with clinical parameters. J Am Soc Echocardiogr 2005; 18: 199-205.
    CrossrefPubMedGoogle Scholar
  • 33 Decker JM. et al. CHADS(2) score is predictive of left atrial thrombus on precar-dio version transesophageal echocardiography in atrial fibrillation. Am J Car-diovasc Dis 2011; 1: 159-165.
    PubMedGoogle Scholar
  • 34 Dorenkamp M. et al. Detection of left atrial thrombus during routine diagnostic work-up prior to pulmonary vein isolation for atrial fibrillation: role of trans-esophageal echocardiography and multidetector computed tomography. Int J Cardiol 2013; 163: 26-33.
    CrossrefPubMedGoogle Scholar
  • 35 Doukky R. et al. B-type natriuretic peptide predicts left atrial appendage thrombus in patients with nonvalvular atrial fibrillation. Echocardiography 2013; 30: 889-895.
    CrossrefPubMedGoogle Scholar
  • 36 Doukky R. et al. External validation of a novel transthoracic echocardiographic tool in predicting left atrial appendage thrombus formation in patients with nonvalvular atrial fibrillation. Eur Heart J Cardiovasc Imaging 2013; 14: 876-881.
    CrossrefPubMedGoogle Scholar
  • 37 Doukky R. et al. The value of diastolic function parameters in the prediction of left atrial appendage thrombus in patients with nonvalvular atrial fibrillation. Cardiovasc Ultrasound 2014; 12: 10.
    CrossrefPubMedGoogle Scholar
  • 38 Fukuda S. et al. Left atrial thrombus and prognosis after anticoagulation therapy in patients with atrial fibrillation. J Cardiol 2011; 58: 266-277.
    CrossrefPubMedGoogle Scholar
  • 39 Gökce M. et al. Factor V Leiden mutation and its relation to left atrial thrombus in chronic nonrheumatic atrial fibrillation. Jpn Heart J 2003; 44: 481-491.
    CrossrefPubMedGoogle Scholar
  • 40 Gu J, Jia F, Feng P. CHADS2versus CHA2DS2-VASc scoring systems for predicting left atrial thrombus in patients with nonvalvular atrial fibrillation. Nan Fang Yi Ke Da Xue Xue Bao 2014; 34: 1601-1605.
    PubMedGoogle Scholar
  • 41 Habara S. et al. Prediction of left atrial appendage thrombi in non-valvular atrial fibrillation. Eur Heart J 2007; 28: 2217-2222.
    CrossrefPubMedGoogle Scholar
  • 42 Hur J. et al. Dual-enhancement cardiac computed tomography for assessing left atrial thrombus and pulmonary veins before radiofrequency catheter ablation for atrial fibrillation. Am J Cardiol 2013; 112: 238-244.
    CrossrefPubMedGoogle Scholar
  • 43 Igarashi Y. et al. Elevated serum lipoprotein(a) is a risk factor for left atrial thrombus in patients with chronic atrial fibrillation: a transesophageal echocar-diographic study. Am Heart J 1998; 136: 965-971.
    CrossrefPubMedGoogle Scholar
  • 44 Iwakura K. et al. Effect of elevated left ventricular diastolic filling pressure on the frequency of left atrial appendage thrombus in patients with nonvalvular at-rial fibrillation. Am J Cardiol 2011; 107: 417-422.
    CrossrefPubMedGoogle Scholar
  • 45 Jaber WA. et al. Comparison of ability to identify left atrial thrombus by three-dimensional tomography versus transesophageal echocardiography in patients with atrial fibrillation. Am J Cardiol 2004; 93: 486-489.
    CrossrefPubMedGoogle Scholar
  • 46 Jung PH. et al. Contrast enhanced transesophageal echocardiography in patients with atrial fibrillation referred to electrical cardioversion improves atrial thrombus detection and may reduce associated thromboembolic events. Car-diovasc Ultrasound 2013; 11: 1.
    CrossrefPubMedGoogle Scholar
  • 47 Kapa S. et al. ECG-gated dual-source CT for detection of left atrial appendage thrombus in patients undergoing catheter ablation for atrial fibrillation. J Interv Card Electrophysiol 2010; 29: 75-81.
    CrossrefPubMedGoogle Scholar
  • 48 Kecoglu S. et al. The effects of eosinophil on the left atrial thrombus in patients with atrial fibrillation. Clin Appl Thromb Hemost 2014; 20: 285-289.
    CrossrefPubMedGoogle Scholar
  • 49 Khan MN. et al. Low incidence of left atrial or left atrial appendage thrombus in patients with paroxysmal atrial fibrillation and normal EF who present for pulmonary vein antrum isolation procedure. J Cardiovasc Electrophysiol 2008; 19: 356-358.
    CrossrefPubMedGoogle Scholar
  • 50 Kimura M. et al. Effect of low-intensity warfarin therapy on left atrial thrombus resolution in patients with nonvalvular atrial fibrillation: a transesophageal echocardiographic study. Jpn Circ J 2001; 65: 271-274.
    CrossrefPubMedGoogle Scholar
  • 51 Kleemann T. et al. Prevalence of left atrial thrombus and dense spontaneous echo contrast in patients with short-term atrial fibrillation < 48 hours undergoing cardioversion: value of transesophageal echocardiography to guide car-dioversion. J Am Soc Echocardiogr 2009; 22: 1403-1408.
    CrossrefPubMedGoogle Scholar
  • 52 Kleemann T. et al. Prevalence and clinical impact of left atrial thrombus and dense spontaneous echo contrast in patients with atrial fibrillation and low CHADS2 score. Eur J Echocardiogr 2009; 10: 383-388.
    CrossrefPubMedGoogle Scholar
  • 53 Maehama T. et al. Systemic inflammation and left atrial thrombus in patients with non-rheumatic atrial fibrillation. J Cardiol 2010; 56: 118-124.
    CrossrefPubMedGoogle Scholar
  • 54 Maltagliati A. et al. Usefulness of multiplane transesophageal echocardiography in the recognition of artifacts and normal anatomical variants that may mimic left atrial thrombi in patients with atrial fibrillation. Ital Heart J 2003; 4: 797-802.
    PubMedGoogle Scholar
  • 55 Maltagliati A. et al. Multidetector computed tomography vs multiplane trans-esophageal echocardiography in detecting atrial thrombi in patients candidate to radiofrequency ablation of atrial fibrillation. Int J Cardiol 2011; 152: 251-254.
    CrossrefPubMedGoogle Scholar
  • 56 Manning WJ. et al. Cardioversion from atrial fibrillation without prolonged anticoagulation with use of transesophageal echocardiography to exclude the presence of atrial thrombi. N Engl J Med 1993; 328: 750-755.
    CrossrefPubMedGoogle Scholar
  • 57 Manning WJ. et al. Prevalence of residual left atrial thrombi among patients with acute thromboembolism and newly recognized atrial fibrillation. Arch Intern Med 1995; 155: 2193-2198.
    CrossrefPubMedGoogle Scholar
  • 58 Martinez MW. et al. Utility of nongated multidetector computed tomography for detection of left atrial thrombus in patients undergoing catheter ablation of atrial fibrillation. JACC Cardiovasc Imaging 2009; 2: 69-76.
    CrossrefPubMedGoogle Scholar
  • 59 Mazouz B. et al. Age: a riskChenzbraun Aleft atrial thrombus in atrial fibrillation. Heart 2008; 94: 197-199.
    CrossrefPubMedGoogle Scholar
  • 60 McCready JW. et al. Incidence of left atrial thrombus prior to atrial fibrillation ablation: is pre-procedural transoesophageal echocardiography mandatory?. Eu-ropace 2010; 12: 927-932.
    CrossrefPubMedGoogle Scholar
  • 61 Nair CK. et al. Thromboembolism in patients with atrial fibrillation with and without left atrial thrombus documented by transesophageal echocardiography. Am J Ther 2009; 16: 385-392.
    CrossrefPubMedGoogle Scholar
  • 62 Nakajima K. The relationship between left atrial thrombus and hematological markers in patients with chronic non-rheumatic atrial fibrillation. Nihon Ronen Igakkai Zasshi 2000; 37: 903-907.
    CrossrefPubMedGoogle Scholar
  • 63 Narumiya T. et al. Relationship between left atrial appendage function and left atrial thrombus in patients with nonvalvular chronic atrial fibrillation and atrial flutter. Circ J 2003; 67: 68-72.
    CrossrefPubMedGoogle Scholar
  • 64 Rader VJ. et al. Clinical predictors of left atrial thrombus and spontaneous echocardiographic contrast in patients with atrial fibrillation. J Am Soc Echoc-ardiogr 2007; 20: 1181-1185.
    CrossrefPubMedGoogle Scholar
  • 65 Ren JF. et al. Left atrial thrombus associated with ablation for atrial fibrillation: identification with intracardiac echocardiography. J Am Coll Cardiol 2004; 43: 1861-1867.
    CrossrefPubMedGoogle Scholar
  • 66 Saeed M. et al. Role of transesophageal echocardiography guided cardioversion in patients with atrial fibrillation, previous leftatrial thrombus and effective anticoagulation. Int J Cardiol 2006; 113: 401-405.
    CrossrefPubMedGoogle Scholar
  • 67 Sakai M. et al. Examinations to detect left atrial thrombus and blood coagulation test analyses in aged patients with atrial fibrillation. Nihon Ronen Igakkai Zasshi 1994; 31: 447-455.
    CrossrefPubMedGoogle Scholar
  • 68 Shen X. et al. Prevalence of intra-atrial thrombi in atrial fibrillation patients with subtherapeutic international normalized ratios while taking conventional anticoagulation. Am J Cardiol 2002; 90: 660-662.
    CrossrefPubMedGoogle Scholar
  • 69 Shen X. et al. Transesophageal echocardiography before cardioversion of recurrent atrial fibrillation: does absence of previous atrial thrombi preclude the need of a repeat test?. Am Heart J 2003; 146: 741-745.
    CrossrefPubMedGoogle Scholar
  • 70 Somlói M. et al. D-dimer determination as a screening tool to exclude atrial thrombi in atrial fibrillation. Am J Cardiol 2003; 92: 85-87.
    CrossrefPubMedGoogle Scholar
  • 71 Srimannarayana J. et al. Prevalence of left atrial thrombus in rheumatic mitral stenosis with atrial fibrillation and its response to anticoagulation: a transesop-hageal echocardiographic study. Indian Heart J 2003; 55: 358-361.
    PubMedGoogle Scholar
  • 72 Stoddard MF. et al. Left atrial appendage thrombus is not uncommon in patients with acute atrial fibrillation and a recent embolic event: a transesophageal echocardiographic study. J Am Coll Cardiol 1995; 25: 452-429.
    CrossrefPubMedGoogle Scholar
  • 73 Stoddard MF. et al. Left atrial thrombus predicts transient ischemic attack in patients with atrial fibrillation. Am Heart J 2003; 145: 676-682.
    CrossrefPubMedGoogle Scholar
  • 74 Stöllberger C. et al. Transesophageal echocardiography to assess embolic risk in patients with atrial fibrillation. ELAT Study Group. Embolism in Left Atrial Thrombi. Ann Intern Med 1998; 128: 630-638.
    CrossrefPubMedGoogle Scholar
  • 75 Stöllberger C. et al. Mortality and rate of stroke or embolism in atrial fibrillation during long-term follow-up in the embolism in left atrial thrombi (ELAT) study. Clin Cardiol 2004; 27: 40-46.
    CrossrefPubMedGoogle Scholar
  • 76 Tang RB. et al. Comparison of contrast enhanced 64-slice computed tomography and transesophageal echocardiography in detection of left atrial thrombus in patients with atrial fibrillation. J Interv Card Electrophysiol 2008; 22: 199-203.
    CrossrefPubMedGoogle Scholar
  • 77 Tang RB. et al. Body mass index and risk of left atrial thrombus in patients with atrial fibrillation. Am J Cardiol 2009; 104: 1699-1703.
    CrossrefPubMedGoogle Scholar
  • 78 Tang RB. et al. Is CHA2DS2-VASc score a predictor of left atrial thrombus in patients with paroxysmal atrial fibrillation?. Thromb Haemost 2011; 105: 1107-1109.
    Article in Thieme ConnectPubMedGoogle Scholar
  • 79 Tani T. et al. Usefulness of electron beam tomography in the prone position for detecting atrial thrombi in chronic atrial fibrillation. J Comput Assist Tomogr 2003; 27: 78-84.
    CrossrefPubMedGoogle Scholar
  • 80 Tsai LM. et al. Role of transesophageal echocardiography in detecting left atrial thrombus and spontaneous echo contrast in patients with mitral valve disease or non-rheumatic atrial fibrillation. J Formos Med Assoc 1990; 89: 270-274.
    PubMedGoogle Scholar
  • 81 Tsai LM. et al. Prevalence and clinical significance of left atrial thrombus in nonrheumatic atrial fibrillation. Int J Cardiol 1997; 58: 163-169.
    CrossrefPubMedGoogle Scholar
  • 82 Uz O. et al. The CHA2DS2-VASc score as a predictor of left atrial thrombus in patients with non-valvular atrial fibrillation. Med Princ Pract 2014; 23: 234-238.
    CrossrefPubMedGoogle Scholar
  • 83 von der Recke G. et al. Use of transesophageal contrast echocardiography for excluding left atrial appendage thrombi in patients withatrial fibrillation before cardioversion. J Am Soc Echocardiogr 2002; 15: 1256-1261.
    CrossrefPubMedGoogle Scholar
  • 84 Wallace TW. et al. Prevalence and clinical characteristics associated with left at-rial appendage thrombus in fully anticoagulated patients undergoing catheter-directed atrial fibrillation ablation. J Cardiovasc Electrophysiol 2010; 21: 849-852.
    PubMedGoogle Scholar
  • 85 Yalcin M. et al. Neutrophil-Lymphocyte Ratio May Predict Left Atrial Thrombus in Patients With Nonvalvular Atrial Fibrillation. Clin Appl Thromb Hemost 2015; 21: 166-171.
    CrossrefPubMedGoogle Scholar
  • 86 Yamamoto M. et al. Complex left atrial appendage morphology and left atrial appendage thrombus formation in patients with atrial fibrillation. Circ Cardiov-asc Imaging 2014; 7: 337-343.
    CrossrefPubMedGoogle Scholar
  • 87 Klein AL. et al. Cardioversion guided by transesophageal echocardiography: the ACUTE Pilot Study. A randomized, controlled trial. Assessment of Cardioversion Using Transesophageal Echocardiography. Ann Intern Med 1997; 126: 200-209.
    CrossrefPubMedGoogle Scholar
  • 88 Klein AL. et al. Assessment of Cardioversion Using Transesophageal Echocar-diography Investigators. Use of transesophageal echocardiography to guide car-dioversion in patients with atrial fibrillation. N Engl J Med 2001; 344: 1411-1420.
    CrossrefPubMedGoogle Scholar
  • 89 Puwanant S. et al. Role of the CHADS2 score in the evaluation of thromboem-bolic risk in patients with atrial fibrillation undergoing transesophageal echoc-ardiography before pulmonary vein isolation. J Am Coll Cardiol 2009; 54: 2032-2039.
    CrossrefPubMedGoogle Scholar
  • 90 Mawatari K. et al. Enhancement of endothelial function inhibits left atrial thrombi development in an animal model of spontaneous left atrial thrombosis. Circ J 2014; 78: 1980-1988.
    CrossrefPubMedGoogle Scholar
  • 91 Dentali F. et al. Incidence of thromboembolic complications in patients with at-rial fibrillation or mechanical heart valves with a subtherapeutic international normalized ratio: a prospective multicenter cohort study. Am J Hematol 2012; 87: 384-387.
    CrossrefPubMedGoogle Scholar
  • 92 Dentali F. et al. Efficacy and safety of direct oral anticoagulants in patients undergoing cardioversion for atrial fibrillation: A systematic review and meta-analysis of the literature. Int J Cardiol 2015; 185: 72-77.
    CrossrefPubMedGoogle Scholar
  • 93 Takasugi J. et al. Dissolution of the left atrial appendage thrombus with riva-roxaban therapy. Cerebrovasc Dis 2013; 36: 322-323.
    CrossrefPubMedGoogle Scholar
  • 94 Mitamura H. et al. Left atrial thrombus formation and resolution during dabi-gatran therapy: A Japanese Heart Rhythm Society report. J Arrhythm 2015; 31: 226-231.
    PubMedGoogle Scholar
  • 95 Lip GY. et al Rationale and design of a study exploring the efficacy of once-daily oral rivaroxaban (X-TRA) on the outcome of left atrial/left atrial appendage thrombus in nonvalvular atrial fibrillation or atrial flutter and a retrospective observational registry providing baseline data (CLOT-AF). Am Heart J 2015; 169: 464-471.
    CrossrefPubMedGoogle Scholar
  • 96 Hur J. et al. Dual-enhanced cardiac CT for detection of left atrial appendage thrombus in patients with stroke: a prospective comparison study with trans-esophageal echocardiography. Stroke 2011; 42: 2471-2477.
    CrossrefPubMedGoogle Scholar