ST Segment Elevation Induced by Class IC Antiarrhythmic Agents: Underlying Electrophysiologic Mechanisms and Insights into Drug-Induced Proarrhythmia

Sodium Block-Induced ST Segment Elevation. Three patients in whom Class IC sodium channel blockers induced ST segment elevation in leads V₁ through V₃ are described. The underlying electrophysiologic mechanism, implications for drug-induced proarrhythmia, and the relationship of the finding to the Brugada syndrome type of idiopathic ventricular fibrillation are discussed.     

非急性心肌梗死ST段抬高的临床意义

心电图ST段抬高主要见于急性心肌梗死,但心电图ST段抬高还可以在其它情况出现。本综述的目的是描述其他心电图上类似心肌梗死的ST段抬高的各种情况,找出与之区分的线索。     

急性心肌缺血与ST段抬高

ST段抬高可见于许多临床病理情况,是冠心病急性心肌缺血进行急诊血运重建的主要标准.目前,ST段抬高的具体分子机制尚未完全明确.现就急性心肌缺血时ST段抬高的可能机制作一综述.     

活动平板运动试验诱发ST段抬高的临床意义

为探讨活动平板运动试验诱发ST段抬高的临床意义 ,分析了 9例无心肌梗死 (简称心梗 )而运动诱发ST段抬高的静息心电图、运动试验及冠状动脉 (简称冠脉 )造影检查结果。结果 :5 0 5 5例行平板运动试验者中 ,有 11例未患心肌梗死而运动诱发心绞痛伴ST段抬高 ,发生率 0 .2 2 %。其中 ,8例患者作了进一步检查 ,冠脉造影显示均有程度不等的血管病变 ,缺血相关血管的狭窄达到 5 0 %～ 10 0 %。ST段抬高导联与缺血相关血管有良好对应关系。另有 1例患者于运动试验 1周后死于心脏性猝死。结论 :无心梗患者运动诱发心电图ST段抬高是冠脉痉挛或冠脉严重狭窄所致心肌局部缺血的标志。     

ST segment elevation in the right precordial leads induced with class IC antiarrhythmic drugs: insight into the mechanism of Brugada syndrome

We evaluated two patients without previous episodes of syncope who showed characteristic ECG changes similar to Brugada syndrome following administration of Class IC drugs, flecainide and pilsicainide, but not following Class IA drugs. Patient 1 had frequent episodes of paroxysmal atrial fibrillation resistant to Class IA drugs. After treatment with flecainide, the ECG showed a marked ST elevation in leads V2 and V3, and the coved-type configuration of ST segment in lead V2. A signal-averaged ECG showed late potentials that became more prominent after flecainide. Pilsicainide, a Class IC drug, induced the same ST segment elevation as flecainide, but procainamide did not. Patient 2 also had frequent episodes of paroxysmal atrial fibrillation. Pilsicainide changed atrial fibrillation to atrial flutter with 2:1 ventricular response, and the ECG showed right bundle branch block and a marked coved-type ST elevation in leads V1 and V2. After termination of atrial flutter, ST segment elevation in leads V1 and V2 continued. In this patient, procainamide and quinidine did not induce this type of ECG change. In conclusion, strong Na channel blocking drugs induce ST segment elevation similar to Brugada syndrome even in patients without any history of syncope or ventricular fibrillation.     

Part IV: Class II,Class III,and Class IV Antiarrhythmic Drugs,Comparative Efficacy of Drugs,and Effect of Drugs on Mortality — A Review of Their Pharmaco kinetics,Efficacy, and Toxicity*

Part IV: Class II, Class III, and Class IV antiarrhythmic drugs, comparative efficacy of drugs, and the effect of drugs on mortality — review of their pharmacokinetics, efficacy, and toxicity. This part reviews the Class II antiarrhythmic agents that share the property of beta adrenergic antagonism, but include several drugs with other unique features. Also reviewed are the Class III agents, which prolong the action potential duration, with a focus on amiodarone. The Class IV agents, which antagonize the calcium channel, are reviewed. Finally, this part reviews the comparative efficacy of antiarrhythmic agents for treatment of ventricular ectopic depolarizations and examines their effect on mortality.     

Differentiation of the Electrophysiological Effects on the Atrial Myocardium Between the Pure Na Channel Blocker, Pilsicainide, and Flecainide

The purpose of this study was to identify the difference between the pure Na channel blocker, pilsicainide and Ic-antiarrhythmic drug, flecainide, on the atrial electrophysiological characteristics. METHODS: The subjects consisted of 24 patients (48 +/- 12 years-old: P-group) in whom pilsicainide was administrated intravenously (1 mg/kg/10 min) and 31 patients (47 +/- 15 years-old: F-group) in whom flecainide was administrated intravenously (2 mg/kg/10 min). The atrial effective refractory period (ERP-A), intra-atrial conduction time (CT), max intra-atrial conduction delay (Max CD), repetitive atrial firing zone (RAFZ), fragmented atrial activity zone (FAZ) and intra-atrial conduction delay zone (CDZ) were measured before and after the drugs. RESULTS: Pilsicainide and flecainide significantly prolonged the ERP-A (211 +/- 27 msec to 246 +/- 39 msec; p < 0.001, 217 +/- 25 msec to 244 +/- 33 msec; p < 0.001, respectively) and CT (121 +/- 33 msec to 149 +/- 43 msec; p < 0.001, 122 +/- 22 msec to 153 +/- 27 msec; p < 0.001, respectively) to the same degree. However, the Max CD was shortened by pilsicainide, but not by flecainide. The RAFZ, FAZ and CDZ decreased in the P-group (21 +/- 25 msec to 4 +/- 10 msec; p < 0.01, 24 +/- 24 msec to 14 +/- 18 msec; p < 0.05, 56 +/- 29 msec to 43 +/- 32 msec, p < 0.05, respectively), but not in the F-group. CONCLUSIONS: The effects of atrial conduction delays may differ between pilsicainide and flecainide. Further examination will be needed to explain this mechanism.     

Rapid Ventricular Response Due to Treatment of Atrial Flutter or Fibrillation with Class IC Antiarrhythmic Drugs

The Class IC antiarrhythmic drugs, propafenone and flecainide, may slow the atrial rate during atrial flutter permitting 1:1 AV conduction. This effect is well known to occur soon after starting treatment for atrial fibrillation or atrial flutter with these Class IC drugs. We report two patients who had adverse effects after prolonged treatment with either propaienone or flecainide. In addition, we illustrate that this adverse effect can occur despite concomitant treatment with drugs that act on the AV node to prevent rapid AV conduction. A.N.E. 2000;5(1):101–104     

急性心肌梗死再灌注治疗后ST段回落的研究进展

ST段回落的分析是急性心肌梗死再灌注疗效的评价方法之一,具有重要的临床意义。现就其分析方法学、影响因素、与心肌再灌注的关系及临床预后的价值予以评价。     

伊布利特合用Ic类药物转复心房颤动/心房扑动的基础与临床

国外伊布利特已广泛应用于转复阵发性心房颤动/心房扑动,近年更有临床研究发现伊布利特与Ic类药物合用时,心房颤动/心房扑动转复成功率增加、而致严重心律失常与单用伊布利特时相当。现对伊布利特与Ic类药物合用的药理基础、临床试验结果及问题和展望等方面作一综述。     

白细胞计数和血小板计数联合评分对急性ST段抬高型心肌梗死患者急诊经皮冠状动脉介入治疗术后在院死亡危险评估的研究

目的：探讨白细胞计数和血小板计数联合评分(COL-P评分)对急性ST段抬高型心肌梗死（STEMI）患者急诊经皮冠状动脉介入治疗（PCI）术后在院死亡危险评估的效果。方法：回顾性研究我院2009-11至2013-08的STEMI住院急诊行PCI术的患者共660例,其中生存者572例,死亡者88例。依不同COL-P评分进行分组（COL-P 0分组、COL-P 1分组、COL-P 2分组）统计学分析。结果：660例急诊行PCI术的STEMI患者住院期间死亡者88例。死亡者白细胞计数高于生存者白细胞计数,两者比较差异有统计学意义（P<0.001）;死亡者血小板计数低于生存者血小板计数,两者比较差异有统计学意义（P<0.01）。Logistic回归显示,COL-P评分[COL-P（1 vs 0）,OR 4.346,95% CI：2.134-8.850,P<0.001; COL-P(2 vs 0), OR 10.126,95% CI：4.061-25.250,P<0.001]为STEMI患者急诊PCI术后在院死亡的独立影响因素。COL-P 0分组、COL-P 1分组和COL-P 2分组在院期间死亡率分别为4.9%、15.4%和43.1%,三组比较差异有统计学意义（P<0.001）。结论：COL-P评分是STEMI患者急诊PCI术后住院期间死亡率危险评估的良好评价工具,但对长期死亡率的评估能力还有待进一步研究验证。     

Acute Myocardial Infarction with Severe ST Segment Elevation Treated with Percutaneous Coronary Intervention More than Two Days after Onset: A Case with Remarkable Recovery

The patient was a 65-year-old man with marked ST-elevation myocardial infarction. Cardiac catheterization revealed an occluded middle portion of the left anterior descending artery and no collateral circulation. Percutaneous coronary intervention (PCI) was performed, and ST elevation improved 5 days after PCI. Almost all electrocardiogram (ECG) findings were normal 6 months later. Echocardiographic findings were also normal. This case was very successful and unusual in that no ventricular aneurysm formed despite ST elevation continuing for a few days and that ECG and left ventricular function were nearly normal after PCI performed days after the onset in a case without collateral circulation.     

Part III: Class IC Antiarrhythmic Drugs—A Review of Their Pharmacokinetics,Electrophysiology, Efficacy,and Toxicity*

Type IC antiarrhythmic agents have unique properties on cardiac tissue. These agents tend to have important effects on phase 0 depolarization and therefore, from an electrocardiographic point of vieia, prolong the QRS complex. Their effect on repolarization is less than that of type IA agents, thus, they generally do not prolong the JT interval, that is the QT minus the QRS. Electrophysiologically, type IC agents prolong refractoriness in many cardiac tissues including atrium, AV node, and ventricle. These unique properties are the focus of this review.     

血浆脑钠尿肽前体水平联合TIMI评分对STEMI患者的预后评估价值

目的：探讨血浆脑钠尿肽前体（NT proBNP）联合心肌梗死溶栓（TIMI）危险评分对ST段抬高性急性心肌梗死（STEMI）患者住院期间及3个月随访期主要心血管事件（MACE ）发生率的预测价值。方法回顾性分析304例STEMI患者入院时血NT proBNP水平及TIMI危险评分。通过绘制受试者工作特征曲线（ROC）及应用Logistic回归分析,确定 NT proBNP 在评分中的分值及其最佳界值,建立 NT proBNP联合TIMI危险评分的新评分系统,比较其与常规TIMI评分对STEMI患者住院期及3个月随访期 MACE发生率预测价值。结果通过 ROC曲线下面积（AUC）分析发现,NTproBNP 的 AUC 为0.732（95%CI 0.670-0.794,P〈0.01）;预测MACE发生率的最佳界值为741。TIMI危险评分的AUC为0.792（95%CI0.735-0.848,P〈0.01）。NT proBNP联合TIMI危险评分的新评分系统的 AUC为0.836（95%CI 0.786-0.885,P〈0.01）,经配对比较,二者比较差异有统计学意义（Z=15.977,P〈0.01）。结论入院时 NTproBNP可以增强TIMI危险评分对 STEMI患者住院期及随访期 MACE发生率的预测价值。     

Comparison of Different Methods of ST Segment Resolution Analysis for Prediction of 1‐Year Mortality after Primary Angioplasty for Acute Myocardial Infarction

Background: Resolution of ST segment elevation corresponds with myocardial tissue reperfusion and correlates with clinical outcome after ST elevation myocardial infarction. Simpler method evaluating the extent of maximal deviation persisting in a single ECG lead was an even stronger mortality predictor. Our aim was to evaluate and compare prognostic accuracy of different methods of ST segment elevation resolution analysis after primary percutaneous coronary intervention (PCI) in a real‐life setting. Methods: Paired 12‐lead ECGs were analyzed in 324 consecutive and unselected patients treated routinely with primary PCI in a single high‐volume center. ST segment resolution was quantified and categorized into complete, partial, or none, upon the (1) sum of multilead ST elevations (sumSTE) and (2) sum of ST elevations plus reciprocal depressions (sumSTE+D); or into the low‐, medium‐, and high‐risk groups by (3) the single‐lead extent of maximal postprocedural ST deviation (maxSTE). Results: Complete, partial, and nonresolution groups by sumSTE constituted 39%, 40%, and 21% of patients, respective groups by sumSTE+D comprised 40%, 39%, and 21%. The low‐, medium‐, and high‐risk groups constituted 43%, 32%, and 25%. One‐year mortality rates for rising risk groups by sumSTE were 4.7%, 10.2%, and 14.5% (P = 0.049), for sumSTE+D 3.8%, 9.6%, and 17.6% (P = 0.004) and for maxSTE 5.1%, 6.7%, and 18.5% (P = 0.001), respectively. After adjustment for multiple covariates only maxSTE (high vs low‐risk, odds ratio [OR] 3.10; 95% confidence interval [CI] 1.11–8.63; P = 0.030) and age (OR 1.07; 95% CI 1.02–1.11; P = 0.002) remained independent predictors of mortality. Conclusions: In unselected population risk stratifications based on the postprocedural ST resolution analysis correlate with 1‐year mortality after primary PCI. However, only the single‐lead ST deviation analysis allows an independent mortality prediction.