Autonomic modulation of the sinus node following electrical cardioversion of persistent atrial fibrillation: relation with early recurrence B Emanuele Bertaglia a, * , Franco Zoppo a , Carlo Bonanno b , Nicola Pellizzari a , Nicoletta Frigato a , Pietro Pascotto a a Department of Cardiology, Ospedale Civile, Via Mariutto, 13, 30135-Mirano (VE), Italy b Ospedale S. Bortolo, Vicenza, Italy Received 29 November 2003; received in revised form 2 April 2004; accepted 5 May 2004 Available online 6 August 2004 Abstract Background: The aim of this study was to correlate early atrial fibrillation (AF) relapses with heart rate variability (HRV) parameters immediately recorded after electrical cardioversion (EC) of persistent AF. Methods and results: We performed the spectral analysis of short-term HRV 30 min after EC in 25 patients with persistent AF. The numbers of patients who maintained sinus rhythm at 48 h, 7, and 30 days were 22, 16, and 14, respectively. A very low low frequency/ high frequency ratio (0.93F0.08 vs. 1.89F1.30; pb0.003) significantly identified patients with AF recurrence at 48 h in comparison to patients without AF recurrence. On the contrary, HRV parameters did not identify patients with AF recurrence at 7 or 30 days. Conclusions: AF relapsed within the first 48 h more frequently in patients who presented a predominant vagal tone immediately after the restoration of sinus rhythm. D 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Modulation; Sinus node; Atrial fibrillation 1. Introduction Restoration of sinus rhythm after atrial fibrillation (AF) is accompanied by the persistence of a high vulnerability to AF, which can easily relapse during the first days [1]. To date, many reports have demonstrated in animal models and humans that this high vulnerability is related to atrial electrophysiological changes (electrical remodeling) [2] , morphological and ultrastructural changes (anatomical remodeling) [3], and modifications of autonomic innervation (autonomic remodeling) occur- ring during AF [4,5]. We wanted to investigate if short-term heart rate variability (HRV) parameters immediately recorded after AF interruption correlate with early AF relapses. 2. Methods 2.1. Patients We investigated 30 patients who underwent an HRV study 30 min after a successful external electrical cardioversion (EC) for a persistent AF lasting more than 30 days. These patients were part of a randomized study aimed to evaluate the effect of bisoprolol pretreatment on early AF recurrences. Patients on oral amiodarone continued their antiarrhythmic treatment. Patients on treatment with other antiarrhythmic drugs withdrew the 0167-5273/$ - see front matter D 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2004.05.013 B The authors have not any conflict of interest in connection with the submitted article. * Corresponding author. Tel.: +39 415794241; fax: +39 415794309. E-mail address: ulss13mirano.elettrofisiologia@wind.it.net (E. Bertaglia). International Journal of Cardiology 102 (2005) 219 – 223 www.elsevier.com/locate/ijcard