This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ammer, R. Articles by Alt, E. Search for Related Content PubMed PubMed Citation Articles by Ammer, R. Articles by Alt, E.

CLINICAL STUDIES

Marked reduction in atrial defibrillation thresholds with repeated internal cardioversion

^a Medizinische Klinik, Klinikum Rechts der Isar der Technischen Universität München, Munich, Germany
^b Deutsches Herzzentrum, Klinik an der Technischen Universität, Munich, Germany

Manuscript received August 6, 1998; revised manuscript received May 20, 1999, accepted June 28, 1999.

Reprint requests and correspondence: Dr. Eckhard Alt, 1. Medizinische Klinik, Klinikum Rechts der Isar, Ismaninger Straße 22, D-81675 München, Germany
alt{at}med1.med.tu-muench.en

OBJECTIVES

This study was performed to assess the atrial defibrillation threshold in patients with recurrent atrial fibrillation (AF) using repeated internal cardioversion.

BACKGROUND

Previous studies in patients with chronic AF undergoing internal cardioversion have shown this method to be effective and safe. However, current energy requirements might preclude patients with longer-lasting AF from being eligible for an implantable atrial defibrillator.

METHODS

Internal shocks were delivered via defibrillation electrodes placed in the right atrium (cathode) and the coronary sinus (anode) or the right atrium (cathode) and the left pulmonary artery. After cardioversion, patients were orally treated with sotalol (mean 189 ± 63 mg/day). Eighty consecutive patients with chronic AF (mean duration 291 ± 237 days) underwent internal cardioversion, and sinus rhythm was restored in 74 patients. Eighteen patients underwent repeated internal cardioversion using the same electrode position and shock configuration after recurrence of AF (mean duration 34 ± 25 days).

RESULTS

In these 18 patients, the overall mean defibrillation threshold was 6.67 ± 3.09 J for the first cardioversion and 3.83 ± 2.62 J for the second (p = 0.003). Mean lead impedance was 55.6 ± 5.1 and 57.1 ± 3.7 , respectively (not significant). For sedation, 6.7 ± 2.9 mg and 3.9 ± 2.2 mg midazolam were administered intravenously (p = 0.003), and the pain score (0 = not felt, 10 = intolerable) was 5.1 ± 1.9 and 2.7 ± 1.8 (p = 0.001). Uni- and multivariate analyses revealed only the duration of AF before cardioversion to be of relevance, lasting 175 ± 113 days before the first and 34 ± 25 days before the second cardioversion in these 18 patients (p = 0.002).

CONCLUSIONS

If the duration of AF is reduced, a significant reduction in defibrillation energy requirements for internal cardioversion ensues. This might extend the group of patients eligible for an implantable atrial defibrillator despite relatively high initial defibrillation thresholds.

Abbreviations and Acronyms   AF = atrial fibrillation   ECG = electrocardiogram

This article has been cited by other articles:

				G. Q. Villani, M. F. Piepoli, and A. Capucci Reproducibility of internal atrial defibrillation threshold in paroxysmal and persistent atrial fibrillation Europace, January 1, 2004; 6(4): 267 - 272. [Abstract] [Full Text] [PDF]

				G. Lehmann, J. Horcher, K. Dennig, A. Plewan, K. Ulm, and E. Alt Atrial Mechanical Performance After Internal and External Cardioversion of Atrial Fibrillation : An Echocardiographic Study Chest, January 1, 2002; 121(1): 13 - 18. [Abstract] [Full Text] [PDF]

				R.E. Ideker and P.C. Fotuhi Early atrial defibrillation; 'a stitch in time saves nine' or 'haste makes waste'? Eur. Heart J., September 1, 2001; 22(17): 1524 - 1526. [PDF]

				P.E. Vardas, E.G. Manios, E.M. Kanoupakis, D.N. Dermitzaki, H.E. Mavrakis, and E.M. Kallergis Atrial defibrillation threshold in humans minutes after atrial fibrillation induction. 'a stitch in time saves nine' Eur. Heart J., September 1, 2001; 22(17): 1613 - 1617. [Abstract] [PDF]