再极化短期变化的增加预测了d-sotalol诱导的狗的torsades de pointes
Morten B Thomsen1, S Cora Verduyn, Milan Stengl
1Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands.
Circulation
|October 13, 2004
概括
再极化的节奏对节奏的变化,特别是短期变化 (STV),预测药物诱导的torsades de pointes失常 (TdP). STV是比QT间隔延长更可靠的预测指标,用于识别有风险的患者.
科学领域:
- 心脏病学 心脏病学
- 电子生理学 电子生理学
- 药理学 药理学是指药理学的学科.
背景情况:
- 鉴定患有药物诱导的torsades de pointes心律失常 (TdP) 风险的患者是具有挑战性的.
- 时间再极化可变性增加是预发性心律失常的潜在预测因素.
- 作为一个预测参数,反极化 (BVR) 的节拍对节拍变异性已被研究.
研究的目的:
- 为了比较药物诱导TdP的不同复极化参数的预测值.
- 调查BVR的作用,量化为短期变化 (STV),在预测TdP.
- 在患有慢性心房阻塞的狗和隔离的心室肌细胞中评估STV.
主要方法:
- 给予d-sotalol麻醉的狗与慢性心房静脉阻塞.
- 使用普安卡尔图表量化BVR和测量STV的左心室单相动力潜力的持续时间.
- 在I(Kr) 阻断后,在隔离的室腔肌细胞中研究了STV.
主要成果:
- 药物诱导的TdP在狗中不仅仅是通过QT延长来解释的.
- TdP发生与左心室单相动作潜能持续时间的STV增加有关.
- 尽管在阿米奥达龙后QT (c) 延长,但TdP的缺失与不变的STV有关.
- 在肌细胞中I(Kr) 阻断后STV增加,与早期脱极化后相关.
结论:
- 前节律失常,特别是TdP,与BVR (量化为STV) 有关,而不是反极化延长的差异.
- 左心室的STV是预测患者药物诱导TdP的潜在新参数.
相关概念视频
01:12Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers
2.9K
Class III antiarrhythmic drugs are a group of medications that can prolong action potentials in the heart. They achieve this by blocking potassium channels or enhancing inward currents from sodium channels. However, these drugs have a unique property of "reverse use-dependence," which is most pronounced at slower heart rates and can lead to torsades de pointes—a specific type of arrhythmia. However, it is essential to note that excessive QT interval prolongation—a measure of...
2.9K
01:20Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers
2.7K
Class IV antiarrhythmic drugs, such as verapamil and diltiazem, block calcium channels. They primarily affect the heart, slowing the conduction in calcium-dependent tissues like the SA and AV nodes. These drugs manage reentrant supraventricular tachycardia (SVT) and reduce ventricular rate in atrial flutter/fibrillation.
Verapamil, a calcium channel blocker, inhibits calcium movement across myocardial cell membranes and vascular smooth muscle. This results in the dilation of coronary and...
Verapamil, a calcium channel blocker, inhibits calcium movement across myocardial cell membranes and vascular smooth muscle. This results in the dilation of coronary and...
2.7K
01:26Heart Failure Drugs: Inotropic Agents
1.9K
Positive inotropic agents are commonly used as the first line of treatment for heart failure. One such agent is digoxin, derived from the genus Digitalis, which has been known for centuries but effectively utilized since 1785. However, these cardiac glycosides can have potentially toxic effects due to their mechanism of action, which involves inhibiting Na+/K+-ATPase and increasing contractility. Digoxin is absorbed orally and distributed in various tissues, including the CNS. It has a long...
1.9K
01:18Dysrhythmias IV: Characteristics of Bradyarrhythmias
788
Bradyarrhythmias are cardiac rhythm disorders characterized by a slower-than-normal heart rate, typically defined as fewer than 60 beats per minute. Some of which are discussed here:Sinus BradycardiaSinus bradycardia presents a heart rate lower than 60 beats per minute, with a regular rhythm originating from the SA node. The ECG typically shows normal P waves preceding each QRS complex, a normal PR interval (0.12 to 0.20 seconds), and a normal QRS duration (0.06 to 0.10 seconds).First-Degree AV...
788
01:25Dysrhythmias VI: Management of Dysrhythmias
597
Dysrhythmia management involves a multifaceted approach, incorporating pharmacological treatments, medical procedures, surgical interventions, lifestyle modifications, and patient education.Pharmacological ManagementAntiarrhythmic Drugs:Class I (Sodium Channel Blockers): This class includes quinidine and procainamide, which reduce the speed of impulse conduction in the heart, stabilize the cardiac membrane, and control arrhythmias. Quinidine and procainamide are Class IA agents that prolong the...
597
01:25ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
1.2K
Arrhythmia is a condition characterized by an irregular heart rhythm, with ECG changes that differ based on its origin and nature. The types of arrhythmias discussed below include atrial, junctional, and ventricular arrhythmias.Atrial ArrhythmiasPremature Atrial Complexes (PACs): PACs are early atrial beats caused by stress, caffeine, alcohol, electrolyte imbalances, hypoxia, hyperthyroidism, or certain medications (e.g., bronchodilators and decongestants). The ECG shows early P waves with an...
1.2K