ObjectiveLeft atrial (LA) thrombus is routinely excluded by transoesophageal echocardiography (TOE) before cardioversion for non-valvular atrial fibrillation (AF). In the D-dimer blood concentrations to exclude LA thrombus in patients with AF study, two D-dimer cut-offs were compared to exclude LA thrombus prior to cardioversion. One was fixed to 500 ng/mL (DD500), based on clinical practice where such values are commonly accepted to exclude a thrombus. The other cut-off was adjusted to 10 times the patient’s age (DDAge), based on the cut-off used to exclude pulmonary embolism.Methods142 consecutive patients with non-valvular AF aged 69.7±11.4 years (52% with paroxysmal AF) referred for precardioversion TOE to exclude LA thrombus were prospectively enrolled. D-dimers were measured at the time of TOE by an ELISA test.ResultsLA thrombus was excluded with TOE in 129 (91%) and confirmed in 13 (9%) patients. D-dimers were significantly lower in patients without LA thrombus (729±611 vs 2376±1081 ng/L; p<0.05). DDAge indicated absence of LA thrombus with higher specificity than DD500 (66.4% vs 50.4%; p<0.05). Both cut-offs were able to identify all 13 patients with LA thrombus (false negative 0%). Patients with D-dimers <DDAge and without LA thrombus (true negative) represented 60.6% of the population and could have safely avoided TOE (flow chart).ConclusionsThis study demonstrates the efficacy of D-dimer cut-offs to exclude LA thrombus in patients with AF. Age adjustment greatly increases the proportion of patients in whom LA thrombus can be safely excluded and consequently avoid precardioversion TOE.

A 51-year-old man with previous history of paroxysmal atrial fibrillation and ischemic stroke presented to the emergency room for progressively worsening dyspnea. Blood tests revealed a significant increase of D-dimer and Nt-proBNP levels. Electrocardiogram and transthoracic echocardiography showed atrial fibrillation with rapid ventricular response rate and concomitant severe impairment of left ventricle systolic function. Transesophageal echocardiography (TEE) showed distinct thrombotic formations: one protruding from the LASP, another in a recessus formed by the ridge limiting the LASP (Figures 1 and 2) and a third-one filling the entire left atrial appendage (Figure 3). Four weeks after implementation of anticoagulation therapy, a new TEE examination revealed full disappearance of all thrombi. AbstractThe left atrial septal pouch (LASP) is a recently identified anatomical variant of the interatrial septum. It is the result of the incomplete fusion of septum primum and septum secundum and defined as a recessus communicating with the left atrium without interatrial shunt. Such anatomical feature has been suspected representing a potential thrombogenic source, but its actual role as risk factor for cryptogenic stroke still remains unclear. In this case report, we show two distinct thrombotic masses emerging from the LASP and its related areas. K E Y W O R D S atrial thrombi, cardiac embolism, left atrial septal pouch, left atrial septum F I G U R E 1 X-plane view of the two thrombi: the first (*) protruding from the LASP and the second (°) attached to the tissue ridge limiting the superior part of the LASP F I G U R E 2 3D view of the position of the two thrombotic formations on the left interatrial septum: the first (*) protruding from the LASP and the second (°) attached to the tissue ridge (dotted line) limiting the superior part of the LASP

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