Correspondence
Atrial Fibrillation
N Engl J Med 2001; 345:620-621August 23, 2001
- Article
To the Editor:
In his review article on atrial fibrillation (April 5 issue),1 Falk suggests that patients admitted to the hospital with atrial fibrillation of less than 48 hours' duration should be treated differently from those with atrial fibrillation of more than 48 hours' duration. He suggests that all patients in whom spontaneous conversion to sinus rhythm does not occur should receive anticoagulation therapy with heparin; however, only those with atrial fibrillation of more than 48 hours' duration should undergo transesophageal-guided cardioversion to exclude the presence of atrial thrombi before cardioversion. Falk's suggestion perpetuates the myth that cardioversion of atrial fibrillation of less than 48 hours' duration is safe without echocardiographic guidance.
The past assumption that 48 hours is insufficient time for thrombi to form has been shown to be incorrect; thrombi occur within a few hours of the development of atrial fibrillation in some patients and are found in 14 percent of patients presenting with acute arrhythmia.2 In our view, the safest way to deal with acute atrial fibrillation is to administer anticoagulation therapy with heparin at presentation. If the patient's fibrillation has not spontaneously reverted and cardioversion during that hospitalization is required, he or she should undergo transesophageal echocardiography before either chemical or electrical cardioversion.
If transesophageal echocardiography is not readily available, the alternative strategy is to give oral anticoagulants for three weeks and then readmit the patient for elective cardioversion, continuing the anticoagulants for a further three to four weeks after the procedure.
2 ReferencesHossan El Gendi, M.R.C.P.
Balvinder Wasan, M.R.C.P.
Jamil Mayet, M.D.
St. Mary's Hospital, London W2 1NY, United Kingdom
j.mayet@ic. ac. uk 1
Falk RH . Atrial fibrillation. N Engl J Med 2001;344:1067-1078
Full Text | Web of Science | Medline2
Stoddard MF ,Dawkins PR ,Prince CR ,Ammash NM . 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;25:452-459
CrossRef | Web of Science | Medline
To the Editor:
Falk's article was an excellent review of atrial fibrillation. It covered the many issues and options that arise in the management of this common arrhythmia. I would like to add a summary, which I have found useful in treating patients with atrial fibrillation and in teaching both house staff and practicing clinicians. I have termed this summary of the management of atrial fibrillation “the five C's of atrial fibrillation”: (1) cause: investigate the cause or triggers of the episode of atrial fibrillation; (2) coagulation: address the need for anticoagulation or antiplatelet therapy; (3) control: control the ventricular rate as necessary; (4) conversion: consider conversion to sinus rhythm, if this is appropriate and desirable; and (5) cure: consider options for long-term maintenance of sinus rhythm — again, if this is an appropriate and desirable strategy for the individual patient.
Although each item may not be applied to every patient, I have found that this is a simple and easily remembered framework on which to approach atrial fibrillation, both in patient care and teaching. I hope that others may find it useful.
David M. Gilligan, M.D.
Veterans Affairs Medical Center, Richmond, VA 23233
davidmgilligan@yahoo.com Author/Editor Response
Dr. Falk replies:
To the Editor: El Gendi et al. state that I suggested that “only those with atrial fibrillation of more than 48 hours' duration should undergo transesophageal-guided cardioversion to exclude the presence of atrial thrombi,” and they imply that there is a need to exclude the presence of atrial thrombi in patients with atrial fibrillation of short duration. They base their objection on a study that included patients who had recently had strokes and that was conducted at a time when monoplane probes for transesophageal imaging were used and the identification of thrombi was less precise than it is today. Unfortunately, they have misread my article and ignored important literature on this topic.
Figure 1 in my review addresses the issue of cardioversion in subjects with an arrhythmia of less than 48 hours' duration. It clearly indicates that this applies to those with “no clinically significant LV [left ventricular] dysfunction, mitral-valve disease, or previous embolism.” These recommendations (which are supported by the consensus conference on antithrombotic therapy of the American College of Chest Physicians1) are based on published data.
In persistent atrial fibrillation, the risk of embolism can be stratified according to clinical criteria that correlate well with the prevalence of thrombi on echocardiographic examination.2 Thus, it is likely that an absence of clinical risk factors in atrial fibrillation of recent onset indicates a low risk of embolism. However, the important questions are not about the prevalence of left atrial thrombi but about the embolic risk of “blind” restoration of sinus rhythm and whether anticoagulation with warfarin can offer a benefit.
Weigner et al. reported on a series of 357 patients with atrial fibrillation lasting 48 hours or less that converted to sinus rhythm during hospitalization without transesophageal examination.3 Two thirds of these patients had spontaneous conversion to sinus rhythm, and only three (0.8 percent) had a clinical embolus. All three events occurred in patients who had spontaneous conversion. This percentage is the same as the rate of embolism in the transesophageal-echocardiography group of the Assessment of Cardioversion Using Transesophageal Echocardiography Study in patients in whom thrombus was not present.4 Given the low risk of embolism in atrial fibrillation of recent onset, the high likelihood of early spontaneous conversion, and the potential for major warfarin-related bleeding (1.5 percent in the warfarin arm of the Assessment of Cardioversion Using Transesophageal Echocardiography Study), the approach of El Gendi et al. is unsupported by evidence of a positive benefit–risk ratio.
I enjoyed Gilligan's mnemonic device for the approach to atrial fibrillation and would simply like to respond to his “five C's” with eight of my own: “Congratulations, colleague, on a concisely compiled, crystal-clear companion to cognition.”
4 ReferencesRodney H. Falk, M.D.
Boston Medical Center, Boston, MA 02118
rfalk@bu.edu 1
Albers GW ,Dalen JE ,Laupacis A ,Manning WJ ,Petersen P ,Singer DE . Antithrombotic therapy in atrial fibrillation. Chest 2001;119:Suppl 1:194S-206S
CrossRef | Web of Science | Medline2
Zabalgoitia M ,Halperin JL ,Pearce LA ,Blackshear JL ,Asinger RW ,Hart RG . Transesophageal echocardiographic correlates of clinical risk of thromboembolism in nonvalvular atrial fibrillation. J Am Coll Cardiol 1998;31:1622-1626
CrossRef | Web of Science | Medline3
Weigner MJ ,Caulfield TA ,Danias PG ,Silverman DI ,Manning WJ . Risk for clinical thromboembolism associated with conversion to sinus rhythm in patients with atrial fibrillation lasting less than 48 hours. Ann Intern Med 1997;126:615-620
Web of Science | Medline4
Klein AL ,Grimm RA ,Murray RD , et al. Use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation. N Engl J Med 2001;344:1411-1420
Full Text | Web of Science | Medline
- Citing Articles (2)
Citing Articles
1
M. Banach, G. Mariscalco, M. Ugurlucan, D. P. Mikhailidis, M. Barylski, J. Rysz. (2008) The significance of preoperative atrial fibrillation in patients undergoing cardiac surgery: preoperative atrial fibrillation--still underestimated opponent. Europace 10:11, 1266-1270
CrossRef2
Maciej Banach, Jacek Rysz, Jarosl«aw Drozdz, Piotr Okonski, Malgorzata Misztal, Marcin Barylski, Robert Irzmanski, Janusz Zaslonka. (2006) Risk Factors of Atrial Fibrillation Following Coronary Artery Bypass Grafting. Circulation Journal 70:4, 438-441
CrossRef
