Akhtar M, Niazi I, Naccarelli G V, Tchou P, Rinkenberger R, Dougherty A H, Jazayeri M
Electrophysiology Laboratory, Sinai Samaritan Medical Center, Milwaukee, Wisconsin 53201.
Am J Cardiol. 1988 Dec 20;62(19):45L-49L. doi: 10.1016/0002-9149(88)90015-x.
Reversal of the electrophysiologic effects of oral encainide with isoproterenol was evaluated in 16 patients with atrioventricular (AV) nodal reentry (group A) and in another 16 patients with Wolff-Parkinson-White syndrome (group B). Sustained AV nodal reentry was induced in all group A cases before administration of encainide, in 2 cases after oral encainide, and in 12 patients during infusion of isoproterenol. Among group B cases, 14 of 16 had sustained AV reentry during control, 6 of 16 after receiving encainide, and 8 of 16 with addition of isoproterenol. During a mean follow-up of 19 +/- 10 months in group A and 17 +/- 9 months in group B, clinical tachycardia recurred in 8 patients (4 from each group). These 8 patients were among the 20 patients who demonstrated (1) isoproterenol-induced reversibility of encainide-suppressed tachycardia, or (2) acceleration of tachycardia rate slowed by encainide. No recurrences were seen among any of the 12 cases in which isoproterenol failed to reverse the encainide-induced tachycardia suppression. Patients with clinical recurrences were controlled with a variety of means, which included beta blockers in 3 and nonpharmacologic methods in the remaining 5. In patients with AV junctional tachycardia treated with oral encainide, our findings suggest that lack of tachycardia inducibility with isoproterenol predicts freedom from clinical recurrences. Furthermore, addition of a beta blocker to oral encainide may prevent clinical recurrence in some who demonstrate adrenergic reversal of encainide effect.
在16例房室结折返患者（A组）和另外16例预激综合征患者（B组）中评估了异丙肾上腺素对口服恩卡胺电生理效应的逆转作用。在A组所有病例中，给药恩卡胺前均诱发了持续性房室结折返，口服恩卡胺后2例诱发，输注异丙肾上腺素期间12例诱发。在B组病例中，16例中有14例在对照期间有持续性房室折返，接受恩卡胺后16例中有6例诱发，加用异丙肾上腺素后16例中有8例诱发。A组平均随访19±10个月，B组平均随访17±9个月，8例患者（每组4例）出现临床心动过速复发。这8例患者属于20例患者中的一部分，这些患者表现为：（1）异丙肾上腺素诱导的恩卡胺抑制性心动过速的逆转，或（2）恩卡胺减慢的心动过速速率加快。在异丙肾上腺素未能逆转恩卡胺诱发的心动过速抑制的12例患者中，均未出现复发。临床复发的患者采用多种方法控制，其中3例使用β受体阻滞剂，其余5例采用非药物方法。对于口服恩卡胺治疗的房室交界性心动过速患者，我们的研究结果表明，异丙肾上腺素不能诱发心动过速预示着无临床复发。此外，在口服恩卡胺的基础上加用β受体阻滞剂可能会预防一些表现出恩卡胺作用的肾上腺素能逆转的患者的临床复发。
