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Predictors of immediate recurrence of atrial fibrillation after external cardioversion
International Journal of Cardiology 91 (2003) 97–98 www.elsevier.com / locate / ijcard
Letter to the Editor
Predictors of immediate recurrence of atrial fibrillation after external cardioversion B. Gorenek*, G. Kudaiberdieva, Y. Cavusoglu, O. Goktekin, A. Birdane, N. Ata, A. Unalir, B. Timuralp Department of Cardiology, Osmangazi University School of Medicine, Eskisehir, Turkey Received 30 July 2002; accepted 31 October 2002
Electrocardiographic changes may be helpful in predicting the occurrence of some atrial arrhythmias [1]. Despite the large number of studies generated by the interest in understanding the mechanisms underlying atrial fibrillation (AF), much remains to be elucidated [2]. Several studies have been undertaken to assess the clinical and electrophysiological risk factors for AF. For example, in a clinical study that examined the risk factors for recurrent AF [3], both maximum P wave duration and P wave dispersion, in addition to age and a history of cardiac disease, were found to be significant univariate predictors of recurrent AF. In multivariate analysis, only maximum P wave duration and age remained as independent predictors [3]. However, the underlying mechanisms and the clinical risk factors for AF are still not clearly established. Electrical cardioversion is an effective way of treating patients with AF. External and intra-atrial shocks are given in an attempt to convert AF to sinus rhythm (SR) with a higher acute success rate of intra-atrial shocks, but similar long-term recurrence rates of AF [4]. Despite successful conversion of AF to SR, the immediate recurrence of AF (IRAF) after cardioversion is a major and largely unpredictable clinical problem and little is known about the mecha*Corresponding author. Tel.: 190-222-239-2476; fax: 190-222-2395370. E-mail address: [email protected] (B. Gorenek).
nisms responsible for IRAF following the use of either of these techniques [5–7]. Immediate reinitiation of AF may be one of the factors determining an unsuccessful electrical cardioversion. However, information on clinical and electrocardiographic predictors of IRAF is very limited. In our hospital, we investigated the possible predictors of IRAF after external cardioversion (EC). Ninety-two patients (42 male, mean age 59610 years, 76 with underlying heart disease) undergoing EC for chronic AF (mean 27618 months) were evaluated. Twelve lead surface ECGs were recorded continuously before and after EC. The maximum P wave duration (Pmax ), the minimum P wave duration (Pmin ), and the P wave dispersion (Pmax 2 Pmin ) were calculated from surface ECG recordings obtained during the first minute of successful EC. Eighty patients had successful EC. Twenty patients (25%) experienced IRAF during the first minute of SR restoration. In 15 of 20 patients (75%), IRAF was initiated by a short–long–short sequence (SLS) due to atrial ectopic beats (AEBs). In these 15 patients, the mean coupling interval was 340 ms. Left atrial dimension (LAD) greater than 60 mm was a strong predictor of IRAF (P,0.001), with a 4.7-fold greater likelihood of recurrence compared to LAD up to 60 mm. Age greater than 65 years was the other strong predictor of IRAF (P,0.01), with a 4.2-fold greater likelihood of developing AF recurrence compared to age less than 65 years. Gender was not an indepen-
0167-5273 / 03 / $ – see front matter 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016 / S0167-5273(02)00600-9
98
B. Gorenek et al. / International Journal of Cardiology 91 (2003) 97–98
dent predictor of AF recurrence. The P wave dispersion was significantly higher in patients with recurrence of AF after EC than without recurrence (4867 vs. 26614 mm, P,0.01). The presence of markedly higher P wave dispersion (.44 ms) was an independent predictor of recurrence (P,0.01). Compared with patients maintaining SR, the patients with IRAF had a lower percentage of antiarrhythmic drug use, especially amiodarone (P,0.06). Patients who remained in SR tended to have shorter AF duration before EC (22612 vs. 41632 weeks, P,0.08). Our data indicate that, in the presence of SLS due to AEBs, significantly enlarged LAD, older age [8] and P wave dispersion are independent predictors of AF recurrence after EC. Antiarrhythmic drug use and AF duration before EC might affect the possibility of recurrence of AF. Further studies are required for an understanding of the mechanisms of IRAF after EC.
References [1] Li W, Xiao HB, Henein MY et al. Progressive ECG changes before the onset of atrial flutter in adult congenital heart disease patients. Heart 2001;85:703.
[2] Allessie MA, Boyden PA, Camm AJ et al. Pathophysiology and prevention of atrial fibrillation. Circulation 2001;103:769–77. [3] Dilaveris PE, Gialafos EJ, Andrikopoulos GK et al. Clinical and electrocardiographic predictors of recurrent atrial fibrillation. Pacing Clin Electrophysiol 2000;23:352–8. [4] Levy S, Lauribe P, Dolla A et al. A randomized comparison of external and internal cardioversion of chronic atrial fibrillation. Circulation 1992;86:1415–20. [5] Baker BM, Botteron GW, Smith JM. Low energy internal cardioversion for atrial fibrillation resistant to external cardioversion. J Cardiovasc Electrophysiol 1995;6:44–7. [6] Smith BM, Alt E, Plewan A et al. Low energy intracardiac cardioversion after failed conventional external cardioversion of atrial fibrillation. J Am Coll Cardiol 1996;28:994–9. [7] Saksena S, Phakash A. Atrial defibrillation: techniques and clinical ¨ results. In: Saksena S, Luderitz B, editors, Interventional electrophysiology. A textbook, 2nd ed., New York: Futura, 1996, pp. 509–20. [8] National Center for Health Statistics. Vital statistics of the United States, 1998, vol. 2: mortality, part A. Washington, DC: Public Health Service, 1991.
Letter to the Editor
Predictors of immediate recurrence of atrial fibrillation after external cardioversion B. Gorenek*, G. Kudaiberdieva, Y. Cavusoglu, O. Goktekin, A. Birdane, N. Ata, A. Unalir, B. Timuralp Department of Cardiology, Osmangazi University School of Medicine, Eskisehir, Turkey Received 30 July 2002; accepted 31 October 2002
Electrocardiographic changes may be helpful in predicting the occurrence of some atrial arrhythmias [1]. Despite the large number of studies generated by the interest in understanding the mechanisms underlying atrial fibrillation (AF), much remains to be elucidated [2]. Several studies have been undertaken to assess the clinical and electrophysiological risk factors for AF. For example, in a clinical study that examined the risk factors for recurrent AF [3], both maximum P wave duration and P wave dispersion, in addition to age and a history of cardiac disease, were found to be significant univariate predictors of recurrent AF. In multivariate analysis, only maximum P wave duration and age remained as independent predictors [3]. However, the underlying mechanisms and the clinical risk factors for AF are still not clearly established. Electrical cardioversion is an effective way of treating patients with AF. External and intra-atrial shocks are given in an attempt to convert AF to sinus rhythm (SR) with a higher acute success rate of intra-atrial shocks, but similar long-term recurrence rates of AF [4]. Despite successful conversion of AF to SR, the immediate recurrence of AF (IRAF) after cardioversion is a major and largely unpredictable clinical problem and little is known about the mecha*Corresponding author. Tel.: 190-222-239-2476; fax: 190-222-2395370. E-mail address: [email protected] (B. Gorenek).
nisms responsible for IRAF following the use of either of these techniques [5–7]. Immediate reinitiation of AF may be one of the factors determining an unsuccessful electrical cardioversion. However, information on clinical and electrocardiographic predictors of IRAF is very limited. In our hospital, we investigated the possible predictors of IRAF after external cardioversion (EC). Ninety-two patients (42 male, mean age 59610 years, 76 with underlying heart disease) undergoing EC for chronic AF (mean 27618 months) were evaluated. Twelve lead surface ECGs were recorded continuously before and after EC. The maximum P wave duration (Pmax ), the minimum P wave duration (Pmin ), and the P wave dispersion (Pmax 2 Pmin ) were calculated from surface ECG recordings obtained during the first minute of successful EC. Eighty patients had successful EC. Twenty patients (25%) experienced IRAF during the first minute of SR restoration. In 15 of 20 patients (75%), IRAF was initiated by a short–long–short sequence (SLS) due to atrial ectopic beats (AEBs). In these 15 patients, the mean coupling interval was 340 ms. Left atrial dimension (LAD) greater than 60 mm was a strong predictor of IRAF (P,0.001), with a 4.7-fold greater likelihood of recurrence compared to LAD up to 60 mm. Age greater than 65 years was the other strong predictor of IRAF (P,0.01), with a 4.2-fold greater likelihood of developing AF recurrence compared to age less than 65 years. Gender was not an indepen-
0167-5273 / 03 / $ – see front matter 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016 / S0167-5273(02)00600-9
98
B. Gorenek et al. / International Journal of Cardiology 91 (2003) 97–98
dent predictor of AF recurrence. The P wave dispersion was significantly higher in patients with recurrence of AF after EC than without recurrence (4867 vs. 26614 mm, P,0.01). The presence of markedly higher P wave dispersion (.44 ms) was an independent predictor of recurrence (P,0.01). Compared with patients maintaining SR, the patients with IRAF had a lower percentage of antiarrhythmic drug use, especially amiodarone (P,0.06). Patients who remained in SR tended to have shorter AF duration before EC (22612 vs. 41632 weeks, P,0.08). Our data indicate that, in the presence of SLS due to AEBs, significantly enlarged LAD, older age [8] and P wave dispersion are independent predictors of AF recurrence after EC. Antiarrhythmic drug use and AF duration before EC might affect the possibility of recurrence of AF. Further studies are required for an understanding of the mechanisms of IRAF after EC.
References [1] Li W, Xiao HB, Henein MY et al. Progressive ECG changes before the onset of atrial flutter in adult congenital heart disease patients. Heart 2001;85:703.
[2] Allessie MA, Boyden PA, Camm AJ et al. Pathophysiology and prevention of atrial fibrillation. Circulation 2001;103:769–77. [3] Dilaveris PE, Gialafos EJ, Andrikopoulos GK et al. Clinical and electrocardiographic predictors of recurrent atrial fibrillation. Pacing Clin Electrophysiol 2000;23:352–8. [4] Levy S, Lauribe P, Dolla A et al. A randomized comparison of external and internal cardioversion of chronic atrial fibrillation. Circulation 1992;86:1415–20. [5] Baker BM, Botteron GW, Smith JM. Low energy internal cardioversion for atrial fibrillation resistant to external cardioversion. J Cardiovasc Electrophysiol 1995;6:44–7. [6] Smith BM, Alt E, Plewan A et al. Low energy intracardiac cardioversion after failed conventional external cardioversion of atrial fibrillation. J Am Coll Cardiol 1996;28:994–9. [7] Saksena S, Phakash A. Atrial defibrillation: techniques and clinical ¨ results. In: Saksena S, Luderitz B, editors, Interventional electrophysiology. A textbook, 2nd ed., New York: Futura, 1996, pp. 509–20. [8] National Center for Health Statistics. Vital statistics of the United States, 1998, vol. 2: mortality, part A. Washington, DC: Public Health Service, 1991.