LETTER TO THE EDITOR
Value of precardioversion transesophageal echocardiography in managing cardioversion of atrial fibrillation
Warren J. Manning, MD*,
David I. Silverman, MD ,
Todd B. Seto, MD, MPH and
Marilyn J. Weigner, MD
* Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Ave, Boston, MA 02215, USA
University of Connecticut, Health Center, Hartford, CT, USA
The Queens Medical Center, Honolulu, HI, USA
Rhode Island Hospital, Providence, RI, USA
wmanning{at}caregroup.harvard.edu
We read with great interest the report of Seidl et al. (1) regarding the value of pre-cardioversion transesophageal echocardiography (TEE) in the management of cardioversion of atrial fibrillation among patients who had already received conventional therapy of three weeks of therapeutic (INR >2) warfarin. Though a similarly low (0.8%) clinical thromboembolism rate was reported among those who underwent TEE prior to cardioversion and those who did not undergo TEE before cardioversion, we respectfully disagree with the researchers’ conclusion that "the use of TEE-guided electrical cardioversion does not reduce the [clinical] embolic risk." Such a conclusion can only be supported by studies in which all patients undergo cardioversion irrespective of the TEE data.
Although the overall clinical thromboembolism rate was similar among both groups in the Seidl et al. study, high-risk patients—those with TEE evidence of left atrial thrombi and those with moderate or severe spontaneous echocardiographic contrast—did not undergo cardioversion. This very likely reduced the overall thromboembolism rate among the TEE group. Furthermore, the frequency of recognized clinical risk factors for stroke, including prior transient ischemic event/stroke and depressed left ventricular ejection fraction, proved significantly higher in the TEE group. This may partially explain the relatively high frequency of left atrial thrombi and dense spontaneous echocardiographic contrast in the TEE group.
We believe that clinical thromboembolism after direct current (DC) cardioversion is related both to migration of thrombi present at the time of cardioversion and to the formation (and migration) of thrombi in the post-cardioversion period (2). Data from our group (3) and the Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) trial (4) support equivalence for conventional therapy and TEE-guided early cardioversion approaches. Though we had previously considered the combination of three weeks of warfarin followed by TEE to be unnecessary and relatively cost-ineffective (5) we interpret the data by Seidl et al. as suggesting that such an approach should now be more fully explored.
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References
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1. Seidl K, Rameken M, Drögemüller A, et al. Embolic events in patients with atrial fibrillation and effective anticoagulation: value of transesophageal echocardiography to guide direct-current cardioversion: final results of the Ludwigshafen Observational Cardioversion Study. J Am Coll Cardiol. 2002;39:1436–1442[Abstract/Free Full Text]
2. Silverman DI, Manning WJ. Current perspective: role of echocardiography in patients undergoing elective cardioversion of atrial fibrillation. Circulation. 1998;98:479–486
3. Weigner MJ, Thomas LR, Patel U, et al. Transesophageal-echocardiography-facilitated early cardioversion from atrial fibrillation: short-term safety and impact on maintenance of sinus rhythm at 1 year. Am J Med. 2001;110:694–702[CrossRef][Medline]
4. Assessment of Cardioversion Using Transesophageal Echocardiography investigatorsKlein AL, Grimm RA, Murray RD, et al. Use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation. N Engl J Med. 2001;244:1411–1420
5. Seto TB, Taira DA, Manning WJ. Do all patients with atrial fibrillation need transesophageal echocardiography before elective cardioversion? A cost-effectiveness analysis. Circulation. 1996;94:I572
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