Prevalence of left atrial chamber and appendage thrombi in patients with atrial flutter and its clinical significance

Abstract

The findings of a low prevalence of LA appendage thrombi (1%) in patients with AFl and a close correlation between a history of previous embolism and paroxysmal AF support the current guidelines that patients with pure AFl do not require anticoagulation therapy, whereas patients with AFl and paroxysmal AF should receive anticoagulation therapy. In addition, the presence of clinical risk factors should alert the physician to an increased likelihood for a thrombogenic milieu.

TEE screening in Atrial flutter: A single-centre experience with retrospective validation of a new risk score for the presence of atrial thrombi

“…Our study does confirm previous reports where pAFl patients undergoing CV have a low prevalence of AT (3% in our population) while AFl patients with previous AF history had a much higher prevalence of AT (32%) [3][4][5][6][7].…”

“…Prevalence of AT and LASEC during atrial flutter (AFl) is debated, previous studies report very different results, ranging from 0% to 21% [3][4][5][6][7].…”

“…Current evidence from TEE studies: Studies in AFl and AF performed in the last decade using TEE, although conflictual, have established some crucial points: 1) AFl in patients with a history of AF should be treated exactly as AF, since thromboembolic risk is in this case superimposable, leaving treatment uncertainties only for "pure" Afl [1,2], 2) Compared to AF, pAFl has a lower thromboembolic risk and less atrial stunning [13], 3) Risk of cardioembolic stroke and consequent opportunity for antithrombotic treatment builds from well established risk factors, consistently reported across the studies, among which cardiac rhythm is only one, together with: previous stroke, mitral stenosis, LV dysfunction, absence of MR, diabetes, hypertension, LA diameter, LASEC, LAAeV and LA thrombus, [3][4][5][6][7]9,14] 4) There is evidence from large TEE studies in patients with recent stroke that LAA function (namely emptying velocity) is the most powerful determinant of thrombus formation, independently of the underlying rhythm (sinus rhythm, AFl, or AF) [15]. 5) The simplistic paradigm that cardioembolic stroke occurs after CV because of a pre-existing cardiac thrombus moving peripherically should be reassessed since: a) TEE studies in AF/AFl CV offered strong arguments against it, one among many being the finding that most of post-CV embolic strokes both in AF and AFl occur in patients being cardioverted after a normal TEE, suggesting that if a cardiac thrombus is culprit, either it can not be ruled out by normal TEE at the time of CV or (more probably) it is generated after CV [1,16,17], b) the recent demonstration of safety of CV after 4-week anticoagulation in AF patients with thrombus detected at previous TEE, without repeat TEE, whereas echocardiographers know from their practice that a substantial proportion of thrombi take more time, even 3-4 months, to dissolve [17].…”

Prolonged Rhythm Monitoring for the Detection of Occult Paroxysmal Atrial Fibrillation in Ischemic Stroke of Unknown Cause

“…Whereas some studies suggest that the stroke risk with atrial flutter (an organized, macroreentrant arrhythmia) is similar to that of AF, 13,14 others suggest a continuum of stroke risk that increases with greater atrial rate and disorganization. 15,16 The putative mechanisms of thromboembolism in AF include development of mechanical dysfunction and a proinflammatory and procoagulant state, with resultant thrombus formation in the complex, pectinate-rich structure of the left atrial appendage (LAA) (Figure 1), [17][18][19] although the possibility that AF is merely a marker for the presence of stroke risk factors exists. Moreover, the LAA demonstrates great interindividual morphological heterogeneity.…”

Do Different Atrial Flutter Types Carry the Same Thromboembolic Risk?

“…2,3 This decreases the chance of developing a thrombus by preventing blood stasis in the atrial chambers. 2,[5][6][7][8][9]11 In previous trials, some clinical and echocardiographic predictors for thromboembolism were defined in patients with atrial fibrillation. Several studies evaluating the thromboembolic risk in these patients reported that the prevalence of atrial thrombi is 0-11% 5-10 and the prevalence of spontaneous echo contrast is 6-42%.…”