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Take-Home message for Arrhythmias at the ESC Congress / World Congress of Cardiology 2006

An article from the e-journal of the ESC Council for Cardiology Practice

Two new AHA/ACC/ESC guidelines for atrial fibrillation management and for ventricular arrhythmia management and sudden death are the most important contributions of this congress as they offer :

  • a recommendation for cardioverter-defibrillator implantation for certain patients with left-ventricular dysfunction.
  • a classification regarding the risk factors for thromboembolic complications; aspirin instead of warfarin in patients with only one moderate risk factor is advised.
  • a reasonable alternative to pharmacological therapy to prevent recurrent atrial fibrillation in symptomatic patients with no or little left atrium enlargement is catheter ablation.Other interesting contributions of the congress in the areas of atrial fibrillation management, CRT, and catheter ablation are also summarised in this article.
Arrhythmias and Device Therapy

I – Guidelines for atrial fibrillation management and for ventricular arrhythmia management and sudden death.

The most relevant issue on arrhythmias during the congress was the presentation of the new guidelines of the ESC, which were developed in collaboration with the AHA and the ACC, regarding the management of patients with atrial fibrillation and regarding the management of patients with ventricular arrhythmias or at risk of sudden death. These guidelines are written with the standard classification of indication class and level of evidence of the ESC. (table 1). 

Class I : Evidence and/or general agreement that a given treatment or general procedure is beneficial, useful or effective.
Class II : Conflicting evidence and/or divergence of opinion about the usefulness/efficacy of the treatment or procedure.
Class IIa : Weight of evidence, opinion is in favour of usefulness/efficacy.
Class IIb : Usefulness/efficacy is less well established by evidence/opinion.
Class III : Evidence or general agreement that the treatment or procedure is not useful or effective and in some cases may be harmful.

Level of evidence A : Data derived from multiple randomised clinical trials or meta-analyses.
Level of evidence B : Data derived from a single randomised clinical trial or large non-randomised studies.
Level of evidence C : Concensus of opinion of the experts and/or small studies, retropsective studies, registries.

The ventricular arrhythmia and sudden death guidelines introduce the novelty that patients with left ventricular dysfunction (ejection fraction less than 30-35%) with functional class II-III and more than one year life expectation are considered a class I indication for cardioverter-defibrillator implantation, if they have either an ischemic or a non-ischemic cardiomyopathy.

The atrial fibrillation guidelines provide several new recommendations but among the most important are those regarding thromboembolic complication prevention. The risk factors for thromboembolic complication are now classified :

  • in a high risk group (previous stroke/transient ischemic attack or embolism, mitral stenosis, prosthetic valve),
  • a moderate risk group (heart failure, left ventricular ejection fraction =35%, hypertension, diabetes mellitus, or age =74 years)
  • and a low or less validated risk factor group (age 65-74 years, female gender, coronary artery disease, tirotoxicosis).

The recommended treatment for patients with one high risk factor or two or more moderate risk factors is warfarin. However, interestingly now aspirin is considered an alternative to warfarin for patients with only one moderate risk factor, such as patients up to 74 year old with heart failure, significant left ventricular dysfunction, or hypertension.

Catheter ablation is now considered a reasonable alternative to pharmacological therapy to prevent recurrent atrial fibrillation in symptomatic patients with no or little left atrium enlargement in these new guidelines.

II – Other relevant contributions

A) Atrial Fibrillation

The less aggressive anticoagulation management proposed in the atrial fibrillation guidelines was also supported by Gisuti et al., who studied the bleeding risk of very old (75-92 years) patients on warfarin. They found that the number of patients treated with warfarin which is needed to show a benefit was similar to that one needed to develop a treatment complication in patients with CHADS2 1 score. Therefore, they suggested that the indication of oral anticoagulation in this group of patients is questionable.

A substudy of the ACTIVE-W was presented, which compared oral anticoagulation vs clopidogrel and aspirine in two patient populations with persistent/permanent or paroxysmal atrial fibrillation.  No differences in stroke or thomboembolic complications were found between paroxysmal and persistent/permanent atrial fibrillation. However, oral anticoagulation was superior to the combined antiplatelet therapy for stroke and thromboembolic prevention in both populations.

Interesting prophylactic effects of polyunsaturated fatty acids n-3 (PUFA) and of atrovastatin on atrial fibrillation relapse after electrical cardioversion and on postoperative atrial fibrillation respectively were presented by Nodarie et al and by Patti et al.

B) Cardiac Resynchronisation Therapy

River-Ayerza et al presented a metanalysis of cardiac resynchronisation therapy (CRT) on mortality, which combined the data form the MUSTIC, MUSTIC-AF, MIRACLE, COMPANION, and CARE-HF trials. They found an statistically significant 3.8% absolute reduction and a 29% relative reduction on all cause mortality with the use of CRT and 26 was the number of patients needed to be treated by CRT to show a benefit on mortality. Cardiac resynchronization therapy combined with AV junction ablation also significantly reduced long term mortality compared with rate control in a multicenter study of 243 patients with atrial fibrillation, which was presented by Gasparini et al. 

Another interesting issue was presented by Klug et al regarding the use of prophylactic antibiotics after cardiac device implantation in the PEOPLE multicentre trial. This prospective study, which involved 44 centres and 6134 implants, found a significant 0.35% risk reduction (p=0.03) on postoperative infection of a single dose of antibiotics.

The major field of research on catheter ablation remained linked to atrial fibrillation. Several studies were presented about new devices for mapping or ablation of the pulmonary veins and also about redo procedures and recurrence prediction. 

C) Catheter Ablation

Finally, two interesting studies were presented and selected for the highlight session about ablation in other arrhythmogenic substrates different to atrial fibrillation.

  • The first one, which was  presented by Calo et al., randomised 19 patients with dilated cardiomyopathy and frequent outflow tract ventricular ectopy to ablation or pharmacological treatment. Ventricular ectopy frequency and left ventricular ejection were reduced and improved respectively with radiofrequency ablation.
  • The second study, which was presented by Merino et al. found that the risk of accessory pathway conduction recurrence after 10 minutes of radiofrequency application is irrelevant, especially for left-sided accessory pathways, which renders the conventional practice of waiting 30 minutes following accessory pathway conduction abolition by radiofrequency application unnecessary.

 The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.


Vol5 N°07

Notes to editor

Dr Jose L. Merino,
Arrhythmia Unit, Hospital Universitario La Paz, Spain

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.