Davy J M, Raczka F, Beck L, Piot C
Service de cardiologie B, hôpital Arnaud de Villeneuve, 371, av. du Doyen Gaston Giraud, 34295 Montpellier.
Arch Mal Coeur Vaiss. 2003 May;96 Spec No 4:20-9.
The mechanisms of action of antiarrhythmic drugs at atrial level are multiple. Antiarrhythmics may act at three levels in the prevention of paroxysmal atrial fibrillation: on the arrhythmogenic atrial substrate, the initiating extrasystoles including those of the pulmonary veins, and in the modulation of the autonomic nervous system. However, there are many modes of initiation which are not well understood so that the preventive role of the antiarrhythmic drugs remains imprecise. Cardioversion of persistent atrial fibrillation has been better analysed in healthy hearts: Class I antiarrhythmics in particular, despite their depressive effects on the conduction which are potentially arrhythmogenic, are beneficial by decreasing the number of reentry circuits, prolonging the atrial refractory period on short cycles and, paradoxically, by increasing the period of excitability in AF. All have a preferential action on anisotropic conduction, especially at the pivotal point of reentry. On the other hand, their role in electrophysiological remodelling in the prevention of immediate recurrences and in pathological atria, remains poorly understood. As for atrial flutter, despite many clinical and experimental studies with antiarrhythmics, the current predominant role of radiofrequency ablation greatly limits the value of these pharmacological studies.
抗心律失常药物在心房水平的作用机制是多方面的。抗心律失常药物在预防阵发性心房颤动时可在三个层面发挥作用：作用于致心律失常的心房基质、起始的期前收缩（包括肺静脉的期前收缩）以及调节自主神经系统。然而，存在许多尚不明确的起始模式，因此抗心律失常药物的预防作用仍不确切。在健康心脏中，持续性心房颤动的转复已得到更好的分析：尤其是Ⅰ类抗心律失常药物，尽管它们对传导具有潜在致心律失常的抑制作用，但通过减少折返环数量、在短周期延长心房不应期以及反常地增加房颤时的兴奋期，从而具有益处。所有这些药物对各向异性传导均有优先作用，尤其是在折返的关键点上。另一方面，它们在预防即刻复发和病理性心房中的电生理重构方面的作用仍知之甚少。至于心房扑动，尽管有许多关于抗心律失常药物的临床和实验研究，但目前射频消融的主导作用极大地限制了这些药理学研究的价值。
