[Prevention of atrial arrhythmias by pacing].

Background: Atrial fibrillation is the most frequent arrhythmia. It can impair quality of life considerably. Due to thromboembolic complications it contributes to the patients' morbidity and mortality and to the costs for their medical treatment.
Prevention: In chronic atrial fibrillation there is a need for adequate anticoagulation and heart rate control. In paroxysmal and intermittent atrial fibrillation it should be sought to prevent its progression to chronic atrial fibrillation. Since atrial fibrillation initiates negative processes of remodeling within the atrial myocardium, it has the tendency to perpetuate itself. From a theoretical point of view, it can be expected that all means which prevent episodes of atrial fibrillation or which terminate it immediately after its onset, are able to prevent or at least to delay the progression to chronic atrial fibrillation. Pharmacologic treatment is usually used to prevent recurrences of atrial fibrillation. Based on the actual data it can also be expected that pacemakers with special preventive pacing algorithms are able to reduce the atrial arrhythmic burden. Besides consequent overdrive pacing, more sophisticated algorithms like "suppression of premature atrial contractions", "post exercise response", "automatic rest rate" or "post mode-switch pacing" have been developed. They can be applied either alone or in combination with special lead positions (interatrial septal pacing or pacing of the triangle of Koch) or special stimulation configurations like dual site right atrial pacing or biatrial pacing. These pacing strategies cover the most relevant onset mechanisms of atrial fibrillation. Furthermore, there are algorithms to treat atrial tachyarrhythmias actively by antitachycardia pacing (ATP). First clinical results have shown that about 2/3 of the diagnosed atrial tachyarrhythmias could be terminated by these means immediately after their onset.
Ongoing Trials: This article gives an overview over the principles of pacing in the management of atrial arrhythmias and ongoing clinical trials in this field. Before a definite judgement on the clinical relevance of these new preventive and therapeutic pacing strategies can be given, the results of these ongoing controlled clinical studies have to be analyzed.