1076 July 2001 PACE, Vol. 24 Introduction Atrial fibrillation (AF) is a common arrhyth- mia occurring in 2%–4% of individuals . 60 years old. 1 Although the best strategy concerning its treatment is still unknown, 2–5 most cardiolo- gists nowadays attempt to restore sinus rhythm. This can be achieved with antiarrhythmic medi- cation or with direct current cardioversion. 6–8 The immediate success rate of transthoracic cardiover- sion is quite satisfactory, 9 but without mainte- nance antiarrhythmic treatment the recurrence rate is high. 10 Even with the most intensive an- tiarrhythmic treatment, as shown in recent stud- ies, AF recurs in 14%–50% of patients in the first year 8,11–13 and to a much higher percent if the fol- low-up is extended further. 14 Various factors have been shown to affect the recurrence of the ar- rhythmia, mainly sex, age, AF duration, number of previous recurrences, left atrial dimension or function, signal-averaged P wave duration, and the presence of coronary, pulmonary, or mitral valve disease. 4,15–19 With the use of amiodarone, which is considered the most efficacious antiar- rhythmic agent, left atrial size and even age and etiology of AF have lost some of their predictive significance in some studies. 20 One factor that has not been tested is whether the frequency of atrial premature complexes (APCs) or the presence of runs of supraventricular tachycardia (SVT) ob- served early after cardioversion is predictive of fu- The Prognostic Significance of Atrial Arrhythmias Recorded Early After Cardioversion for Atrial Fibrillation THEMISTOCLIS MAOUNIS,* ELENA KYROZI,* KONSTANTINOS KATSAROS,† ELENI BILIANOU,† VASSILIOS P. VASSILIKOS,* ANTHONY S. MANOLIS,‡ and DENNIS COKKINOS§ From the *First Department of Cardiology, Onassis Cardiac Surgery Center, Athens, †Department of Cardiology, Tzanion State Hospital, Piraeus, ‡Department of Cardiology, University of Patras, Patras, and the §Department of Cardiology, University of Athens, Athens, Greece MAOUNIS, T., ET AL.: The Prognostic Significance of Atrial Arrhythmias Recorded Early After Car- dioversion for Atrial Fibrillation. In a substantial number of patients, AF recurs after successful electri- cal cardioversion. The purpose of this study was to investigate if the atrial arrhythmias recorded immedi- ately after cardioversion are associated with the risk of recurrence of the arrhythmia and to compare the prognostic significance of this parameter with that of other established risk factors. In a series of 71 pa- tients, the risk factors for recurrence of AF during the first year after successful electrical cardioversion were analyzed. A new parameter that was investigated was the frequency of atrial premature beats and the presence of runs of supraventricular tachycardia in the Holter recording started immediately after the cardioversion. Age, left atrial size, left ventricular systolic function, duration of the arrhythmia before car- dioversion, underlying cardiac disease, or medication taken were not found to be predictive of recurrence of the arrhythmia. However, the natural logarithm of the number of atrial premature complexes per hour of the Holter recording in the 37 patients in whom AF recurred was higher compared to that of the 34 pa- tients who maintained sinus rhythm (P , 0.0005). The same was true if only the first 6 hours of the record- ing were analyzed (P , 0.0005). There was a trend for more frequent arrhythmia recurrence if runs of supraventricular tachycardia were present. The finding of . 10 atrial premature complexes per hour in the recording had a relative risk of 2.57 (1.51–4.37), a positive predictive accuracy of 76.5%, and a nega- tive predictive accuracy of 70.3% for subsequent arrhythmia recurrence. We can conclude that frequent (. 10/hour) atrial premature complexes in the Holter recording after electrical cardioversion for AF is a significant risk factor for recurrence of the arrhythmia. (PACE 2001; 24:1076–1081) atrial fibrillation, cardioversion, atrial premature beats Address for reprints: Themistoclis N. Maounis, M.D., 1st De- partment of Cardiology, Onassis Cardiac Surgery Center, Syn- grou Ave. 356, Kallithea-Athens 176 74, Greece. Fax: 13019493331; e-mail: maounis6yahoo.com Received April 24, 2000; revised September 28, 2000; accepted October 26, 2000. Reprinted with permission from JOURNAL OF PACING AND CLINICAL ELECTROPHYSIOLOGY , Volume 24, No. 7, July 2001 Copyright © 2000 by Futura Publishing Company, Inc., Armonk, NY 10504-0418.