リポラライゼーションの短期的な変動性の増加は,犬のd-sotalol誘発のtorsades de pointesを予測する
Morten B Thomsen1, S Cora Verduyn, Milan Stengl
1Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands.
Circulation
|October 13, 2004
まとめ
リポラライゼーションのビート・トゥ・ビート変動性,特に短期変動性 (STV) は,薬物誘発のトーサデス・デ・ポインテス不律症 (TdP) を予測します. STVは,リスクのある患者を特定するために,QT間隔の延長よりも信頼性の高い予測指標です.
科学分野:
- 心臓病学 心臓病学
- 電気生理学 電気生理学
- 薬理学 薬理学とは
背景:
- 薬剤誘発のTorsades de pointes arritmia (TdP) のリスクのある患者を特定することは困難です.
- テンポラルリポラライゼーションの可動性の増加は,プロアリズム症の潜在的予測因子である.
- リポラライゼーションのビート・トゥ・ビート・ヴァイアビリティ (BVR) は,予測パラメータとして調査されています.
研究 の 目的:
- 薬物誘発型TdPの異なるリポラライゼーションパラメータの予測値を比較する.
- 短期変動 (STV) として定量化されるBVRがTdPを予測する上で果たす役割を調査する.
- 慢性的な心房閉塞の犬および孤立した心房筋細胞でSTVを評価する.
主な方法:
- d-sotalolは,慢性的な心房閉塞の麻酔を受けた犬に投与されました.
- プアンカーグラフを用いたBVRの定量化と,左心室単相アクションポテンシャルの持続時間STVの測定.
- I ((Kr)) ブロック後の分離された心室筋細胞で調査されたSTV.
主要な成果:
- 犬における薬物誘発のTdPは,QTの延長によってのみ説明されませんでした.
- TdPの発生は,左心室単相アクションポテンシャル持続時間のSTVの増加と関連していました.
- アミオダロン投与後のQT (c) 延長にもかかわらずTdPの欠如は,変化しないSTVと関連していました.
- STVは,ミオサイトにおけるI(Kr) ブロックの後に増加し,早期のデポラライゼーション後の結果と相関する.
結論:
- プロアリズム,特にTdPは,リポラライゼーション延長の違いではなく,BVR (STVとして定量化) に関連しています.
- 左心室のSTVは,患者における薬物誘発性TdPを予測するための新たなパラメータである.
関連する概念動画
Antiarrhythmic 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
Antiarrhythmic 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
Heart 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
Dysrhythmias 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
Dysrhythmias 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
ECG 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


