Le Franc P, Kuś T, Vinet A, Rocque P, Molin F, Costi P
Research Center, Hôpital du Sacré-Coeur de Montréal, Université de Montréal, Québec, Canada.
Pacing Clin Electrophysiol. 1997 Dec;20(12 Pt 1):2882-92. doi: 10.1111/j.1540-8159.1997.tb05456.x.
Inappropriate shocks can complicate cardioverter defibrillator therapy. Among solutions proposed to avoid oversensing are algorithms to reduce inappropriate detection of atrial fibrillation (AF) or sinus tachycardia. In patients not on antiarrythmic drugs, an interval stability criterion of 40 ms has been validated with the Medtronic PCD to discriminate ventricular tachycardia (VT) from AF. With this algorithm, VT is considered stable if no interval varies from one of the three preceding intervals by more than 40 ms. If an interval does not fulfill this criterion, the VT event counter is reset to zero. The aim of this study was to investigate the incidence of underdetection when this criterion is applied in patients treated with antiarrhythmic drugs. We studied 132 sustained monomorphic VTs induced in 42 patients during 101 electrophysiological studies (EPS). EPS were performed without treatment (group I, 24 patients, 44 VTs); on Class Ia drug (group II, 17 patients, 24 VTs); Class Ic drug (group III, 22 patients, 39 VTs); or sotalol (group IV, 17 patients, 25 VTs). The endocardial electrogram of all VT episodes was digitized and the stability algorithm was applied. The reset arrhythmias were distributed among no delay, small, moderate (< 10 s) and important (> 15 s) delay in VT detection. The relation between drug use and reset was analyzed. Reset was found in 86 (65%) of induced VTs. No difference in heart rate or induction mode was shown between reset and nonreset VTs. There was a significative association between drug use and reset probability (Chi2 significantly different, P < 0.05). In patients treated with Class Ic drugs, the probability of finding an important delay in VT detection was 12.5% versus 0% in nontreated patients or in patients treated with sotalol. We conclude that a stability criterion of 40 ms is probably safe in nontreated patients but should be used with caution in patients treated with antiarrhythmics, especially in the presence of Class Ic drugs.
不适当电击会使心脏复律除颤器治疗变得复杂。为避免过度感知而提出的解决方案中，有一些算法可减少对心房颤动（AF）或窦性心动过速的不适当检测。在未服用抗心律失常药物的患者中，美敦力PCD已验证40毫秒的间期稳定性标准可用于区分室性心动过速（VT）与AF。采用该算法时，如果没有一个间期与前三个间期之一的差异超过40毫秒，则认为VT是稳定的。如果一个间期不符合该标准，则VT事件计数器重置为零。本研究的目的是调查在接受抗心律失常药物治疗的患者中应用该标准时漏检的发生率。我们在101次电生理研究（EPS）期间对42例患者诱发的132次持续性单形性VT进行了研究。EPS在未治疗（I组，24例患者，44次VT）、Ia类药物治疗（II组，17例患者，24次VT）、Ic类药物治疗（III组，22例患者，39次VT）或索他洛尔治疗（IV组，17例患者，25次VT）的情况下进行。对所有VT发作的心内膜电图进行数字化处理并应用稳定性算法。重置的心律失常分布在VT检测无延迟、小延迟、中度延迟（<10秒）和严重延迟（>15秒）中。分析了药物使用与重置之间的关系。在诱发的VT中，有86次（65%）出现重置。重置和未重置的VT在心率或诱发方式上无差异。药物使用与重置概率之间存在显著关联（卡方检验显著不同，P<0.05）。在接受Ic类药物治疗的患者中，VT检测出现严重延迟的概率为12.5%，而未治疗患者或接受索他洛尔治疗的患者为0%。我们得出结论，40毫秒的稳定性标准在未治疗患者中可能是安全的，但在接受抗心律失常药物治疗的患者中应谨慎使用，尤其是在使用Ic类药物的情况下。
