The Advance Of Nonpharmocologic Therapy For Atrial Fibrillation

Atrial fibrillation is the most common consisting tachy-arrthymia, and the incidience of it increases followed ages. The main threatening side effects are thrombembolism and lowering cardiac function that are caused by influenced cardiac contraction during atrial fibrillation. By far there is still less effective pharmacologic therapy for atrial fibrillation, some nonpharmacologic therapies such as Maze surgery ,catheter ablation ,implantable atrial defibrillator and atrial pacing arise and be focused.Based on multiple reentry-circle theory ,Cox firstly developed Maze surgery from type â… ,â…¡ to Maze â…¢ and modified Maze surgery. The current Maze surgery has high efficiency and becomes the compelling operation algorithm .Today, radiofrequency, cryotherapy, echo and microwave are used in surgery instead of physical cutting. In all Maze surgeries ,Maze â…¢ has a compelling registered patients number and clinical effect than others. Although MAZE â…¢ and modified Maze surgery have simplified operation and lessened injury ,they are still restricted in surgical patientsfor it is difficult to consider to use in alone atrial fibrillation patients.Catheter ablation for atrial fibrillation is another promising therapy ,in which AV node ,atrial and pulmonary veins are target ablation sites. Ablation of AV node and pacemaker implantation is a wide used therapy for ventricle heart rate control of patients with atrial fibrillation. While anticoagulation therapy should also be considered to prevent high risk of thrombembolism ,for atrial fibrillation is still existed. Modification of AV node is another nonpharmocologic method to control ventricle heart rate ,but pacemaker implantation is avoided. However its application is restricted for its following clinical effects.Simulated Maze surgery,the arial linear ablation is a cure method to modify atrial substrate. Carto mapping and ablation system can ensure the veracity, continuity and transmural injury of ablation route during operation, so its success rate is similar to Maze surgery and is superior than the traditional ablation method. Pulmonary veins ablation is developed by foci atrial fibrillation theory ,which includes ostial ablation, circumferential ablation and segment ablation methods. The ablation of ostial ablation is achieved by mapping of pulmonary veins to confirm the local foci of atrial fibrillation. But the application of ostial ablation is decreased for its difficulty of stimulation and mapping during ablation ,also the serious side effect of pulmonary vein stenosis. By Carto system and echoballoon catheter , pulmonary vein circumferential ablation is easily achieved and receives better results without stenosis of pulmonary vein. Although echoballoon catheter has a priority for multi-vessel ablation butlonger effect is under investigation. Pulmonary vein segment ablation simplifies the process of circumferential ablation,in which the ablation site is focus on the connection segment of left atria and muscle sleeve of pulmonary veins. The new technology of ICE(introcardiac echocardiography) can promote the efficiency of pulmonary vein segment ablation and prevent the side effect though modulation the power of radiofrequency by observation the micro bubble from echo.In all side effects of intervention ablation for atrial fibrillation the stenosis of pulmonary veins should be more regarded .Avoiding ablation in pulmonary veins, reducing the frequency of discharge and decreasing the power of ablation has been approved to reduce the occurrence of narrowing pulmonary veins. Although the catheter ablation for atrial fibrillation has achieved compromising results ,the success rate for single operation is not satisfied. As far the indication of catheter ablation is atrial fibrillation patients with frequent onset ,obvious symptoms and refractory to antiarrhythmia medicine.IAD(implanted atrial defibrillator) can converted atrial fibrillatuion by discharge in atria. But its application is restricted for the high ratio of cost/effect. Atrial pacing can prevent the onset of atrial fibrillation by elimination the trigger factors for it ,in which includes atrial ectopic beat, prominent bradycardia and intro-atrial conduction block. It is not wide applied for some puzzle of actual operation.In conclusion, nonpharmacologic approaches for atrial fibrillation provide us more choices and catheter ablation, the compromising cure therapy, will certainly bring us to a new times in the near future.