Thromboembolism after negative TEE.
Authors: W J Manning, D I Silverman, P S Douglas
Journal: Circulation (1994)

As in the report of Manning et al,2 anticoagulation management was not uniform in the present series,' reflecting physician judgements regarding the requirement for and contraindications to anticoagulation.Our study did not address the optimal duration of anticoagulation after cardioversion, which may depend on the time course of atrial function after cardioversion6 and the likelihood of arrhythmia recurrence.Most cases of cardioversion-related embolism occur in the first week after cardioversion.'78Although the minimum anticoagulation duration of 24 hours after cardioversion recommended by Manning et al may provide some benefit, it appears prudent to continue anticoagulation after cardioversion for at least one week and as long as one month, until further data are available.As noted in the discussion,' the 2.4% incidence of embolism in our study overestimates the true incidence of embolism after TEE-guided cardioversion, as the denominator of 712 patients was drawn only from centers in which embolic events occurred.How- ever, this incidence is consistent with the 95% confidence intervals for embolism of 0-4.6% in Manning's study2 and is comparable with the incidence reported by Arnold et al.8Although we agree with Manning et al that TEE is helpful for patients in whom anticoagulation is absolutely contraindicated, clinicians should understand the potential risks of such an approach.The possibility that thrombus may have developed before cardio- version in the three patients with delays after TEE has already been addressed in our paper.'As in Dr Manning's study,2 a minority of our patients was studied with single plane TEE.Their study2 showed no difference in the sensitivity of the transverse and longitudinal planes for left atrial thrombi.Nevertheless, we recom- mend that TEE-guided cardioversion be performed using biplane or multiplane TEE probes.Finally, we note that this multicenter cooperative study included all cases of embolism after TEE-guided cardioversion known to the investigators, including seven patients included in other studies.This multicenter approach enabled com- prehensive, uniform evaluation of all known cases.In response to Dr Josephson's remarks, there was no "two year hiatus" in data collection.None of the patients undergoing TEE-guided cardioversion in 1989 or 1990 had embolic events.Quality control is an important issue, which we specifically ad- dressed.All videotapes were independently overread by an experienced echocardiographer, and all studies except one unavailable videotape were reviewed in a central reference laboratory.The absence of atrial thrombus was confirmed in all cases.Excluding the 50% of patients with atrial fibrillation who have left atrial "smoke" from cardioversion is not the practice of physicians experienced with the procedure, except in occasional cases when left atrial thrombus cannot be confidently excluded or the patient is not therapeutically anticoagulated.It is clear from our study that no precardioversion characteristic reliably predicts patients at risk of embolism after cardioversion.