J Thorac Cardiovasc Surg 1998;115:485
© 1998 Mosby, Inc.
Outcome of atrial fibrillation after mitral valve repair
Anoop K. Ganjoo, MCh, DNB, FIACS
To the Editor:
The article by Obadia and associates
1 in the August 1997 issue of this Journal evaluates some of the factors that influence the return to sinus rhythm (SR) from preoperative atrial fibrillation (AF) after mitral valve repair. I shall only be referring to those patients whom the authors have called the permanent fibrillation group (about 70% of their patients with AF). Duration of AF was the most important factor identified, being more predictive than left atrial diameter. Although this is widely acknowledged to be the case, another prognostic factor that helps to identify patients whose rhythm is likely to revert to SR, and possibly continue in SR in the late postoperative period, is the outcome of primary cardioversion intraoperatively.
I would like to share our experience with patients in AF undergoing mitral valve replacement (MVR), which we published some years back 2 and believe is equally pertinent in mitral valve repair.
In all patients with AF who were undergoing MVR, we tried intraoperative direct-current cardioversion (primary cardioversion) soon after separation from cardiopulmonary bypass. Synchronized shocks of 10 to 50 joules were delivered to the heart, and attempts were made to capture the SR, if present, on biatrial pacing. Pacing was continued for 48 to 72 hours after the operation if this primary cardioversion was successful. Logically, such patients (group A) would be in a superior hemodynamic state in the critical postoperative period in the intensive care unit than those whose rhythm did not convert to SR (group B). All discharged patients of group B, and those of group A whose rhythm reverted to AF after only a few days of SR, were called back for a secondary cardioversion after varying intervals in the postoperative follow-up. We studied 75 such patients prospectively over a 4-year period.
We observed that the results of secondary cardioversion were much better in group A patients (80.9% immediate conversion to SR) than in group B (36.4% conversion to SR). Also, at the end of 1 year, 55.5% of group A patients and only 19.3% in group B were still in SR. The most likely candidate for a successful cardioversion in our study was a patient with a duration of AF less than 2 years and in whom it was possible to convert to SR at the time of the operation. On the basis of these conclusions, we recommended that all patients in AF undergoing MVR should have an electric cardioversion during the operation. If successful, SR should be maintained by atrial pacing for 48 to 72 hours for a smoother immediate postoperative recovery. When discharged patients in AF are called in for a secondary cardioversion, success is more likely if the response to primary cardioversion was positive, even if the SR did not last long.
Specialist, Cardiothoracic SurgerySt. Stephen's HospitalTis Hazari,
Delhi 110054 India
References
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Obadia JF, Farra ME, Bastien OH, Lièvre M, Martelloni Y, Chassignolle JF. Outcome of atrial fibrillation after mitral valve repair. J Thorac Cardiovasc Surg 1997;114:179-85.[Abstract/Free Full Text]
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Ganjoo AK, Kaul U, Iyer KS, Das B, Rao IM, Kumar AS, et al. Direct current cardioversion for atrial fibrillation after mitral valve replacement. Ind Heart J 1987;39:312-7.
