Correspondence

Atrial Arrhythmia in Atrial Septal Defect

N Engl J Med 1999; 341:540-541August 12, 1999

Article

To the Editor:

Gatzoulis et al. (March 18 issue)1 report that adult patients are more likely to have persistent atrial fibrillation and atrial flutter or to have these arrhythmias after surgical closure of an atrial septal defect if they are older than 40 years at the time of surgery or have these arrhythmias preoperatively. The authors explain why they did not include data on right atrial volume in their analysis. However, these data could be the missing link. It is well known that longer periods of left-to-right shunting lead to excessive dilatation of the right atrial chamber, with a subsequent risk of atrial arrhythmia. Moreover, several studies have documented the poor outcome of medical and electrical treatment of chronic atrial fibrillation in patients with severely enlarged atria.2

Another important and unmentioned factor is the duration of atrial arrhythmia before surgery. Wijffels et al. stated that “atrial fibrillation begets atrial fibrillation,”3 and one could assume that in the group of patients studied by Gatzoulis et al., a longer preoperative duration of atrial fibrillation or atrial flutter increased the probability that the abnormality would remain after closure of the atrial septal defect.

Viviane Conraads, M.D.
Adriaan C. Moulijn, M.D., Ph.D.
Chris J. Vrints, M.D., Ph.D.
University Hospital Antwerp, B-2650 Edegem, Belgium

3 References

1. 1

   Gatzoulis MA, Freeman MA, Siu SC, Webb GD, Harris L. Atrial arrhythmia after surgical closure of atrial septal defects in adults. N Engl J Med 1999;340:839-846
   Full Text | Web of Science | Medline

2. 2

   Van Gelder IC, Crijns HJ, Van Gilst WH, Verwer R, Lie KI. Prediction of uneventful cardioversion and maintenance of sinus rhythm from direct-current electrical cardioversion of chronic atrial fibrillation and flutter. Am J Cardiol 1991;68:41-46
   CrossRef | Web of Science | Medline

3. 3

   Wijffels MC, Kirchhof CJ, Dorland R, Allessie MA. Atrial fibrillation begets atrial fibrillation: a study in awake chronically instrumented goats. Circulation 1995;92:1954-1968
   Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: We acknowledged that long-standing right atrial dilatation may have contributed to the arrhythmogenic substrate in our patients. All 149 of our patients who underwent cardiac catheterization had substantial left-to-right shunts, as evidenced by a Qp:Qs ratio of more than 1.5. There was no significant difference, however, in the magnitude of the left-to-right shunts between patients who presented with arrhythmia and those who were in sinus rhythm at the time of surgery.

We elected to consider patients who presented with atrial arrhythmia — chronic or paroxysmal atrial flutter and fibrillation — as a single group. There was no significant difference, however, in terms of the frequency of postoperative conversion to sinus rhythm between patients who presented with paroxysmal atrial tachyarrhythmia and those with chronic atrial flutter and fibrillation. This finding suggests that once sustained arrhythmia develops in this population, patients are indeed at risk for postoperative arrhythmia after closure of an atrial septal defect.

Michael A. Gatzoulis, M.D., Ph.D.
Royal Brompton Hospital, London SW3 6NP, United Kingdom

Louise Harris, M.B., Ch.B.
Toronto General Hospital, Toronto, ON M5G 2C4, Canada