変な流れのダウンレギュレーションと,心房タキアリズムと関連したシヌスノード機能障害: タキカルディア・ブラディカルディア症候群の分子基礎
Yung-Hsin Yeh1, Brett Burstein, Xiao Yan Qi
1Department of Medicine, Montreal Heart Institute Research Center and Université de Montréal, Montreal, Quebec, Canada.
Circulation
|March 18, 2009
まとめ
アトリヤ・タキアリズム (ATs) は,鍵となるイオンチャネル発現,特に面白い電流 (I) を減少させることにより,シノアトリヤ・ノード (SAN) の機能を損なう. このイオンチャネル改造は,SAN機能不全と関連する不律に寄与する.
科学分野:
- 心臓病学 心臓病学
- 電気生理学 電気生理学
- 分子生物学は分子生物学である.
背景:
- シノアトリアルノード (SAN) 機能不全は,しばしば心房タキアリズム (ATs) と関連付けられています.
- AT後のSAN機能障害は昏睡につながり,ペースメーカーのインプラントが必要になります.
- AT誘発のSAN機能障害の背後にあるメカニズムは完全に理解されていません.
研究 の 目的:
- ATがイオンチャネル発現を変化させることでSAN機能を損なうかどうかを調査する.
- ATsの影響を受ける特定のイオンチャネルとサブユニットを特定するために.
- イオンチャネル発現の変化とSAN細胞の機能的欠陥を相関させるため.
主な方法:
- SAN組織は,対照犬と7日間の心房不動脈縮小手術を受けた犬から採取されました.
- 全細胞パッチクランプ技術を使用して,単一のSAN細胞のイオン電流を測定しました.
- リアルタイム逆転写ポリメラーゼ連鎖反応 (RT-PCR) は,鍵となるイオンチャネルサブユニットの定量化mRNA発現.
主要な成果:
- アトリアル・タチペーシングは,SANの回復時間を大幅に増加させ,機能障害を示唆しました.
- HCN2,HCN4,およびminKサブユニットの発現は,タチパスのSAN.で有意に減少しました.
- 変な電流 (I(f)) と遅い遅延補正電流 (I(Ks)) の密度が低下し,I(f) の変化は主に遅い SAN 周期性を説明しました.
- 他の主要なチャネル (I(Kr),I(Ks),I(CaL,I(CaT,コネクシン 43) の発現は影響を受けなかった.
結論:
- アトリアルタキアリズム症は,SAN HCN2/4とminKサブユニット発現をダウンレギュレーションします.
- これにより,I(f) とI(Ks) の電流が減少し,SANの機能不全に寄与します.
- SANイオンチャネル,特にI (f) の高動脈誘発による改造は,ATとSAN機能障害との関連における重要な要因である.
関連する概念動画
ECG Interpretation of Arrhythmias I: Sinus Arrhythmias
Arrhythmias are disturbances in the heart's rhythm that lead to abnormal heartbeats. These irregularities can originate from different parts of the heart and are classified based on their origin and nature.
Types of Arrhythmias
Sinus Node Arrhythmias
Sinus Bradycardia: Originating from the sinoatrial (SA) node, sinus bradycardia involves slower impulses, resulting in a heart rate of less than 60 beats per minute (bpm). Causes include sleep, vagal stimulation, beta-blockers, hypothyroidism, and...
Types of Arrhythmias
Sinus Node Arrhythmias
Sinus Bradycardia: Originating from the sinoatrial (SA) node, sinus bradycardia involves slower impulses, resulting in a heart rate of less than 60 beats per minute (bpm). Causes include sleep, vagal stimulation, beta-blockers, hypothyroidism, and...
Mechanism of Cardiac Arrhythmias
Arrhythmias are irregular heart rhythms occurring when the heart's electrical impulses become abnormal. These disturbances can lead to various symptoms, depending on their severity and the underlying cause. Some common factors contributing to arrhythmias include hypoxia, ischemia, electrolyte imbalances, excessive catecholamine exposure, drug toxicity, and muscle overstretching. Arrhythmias can be classified into two main types based on the rate and site of origin of abnormal heart rhythms.
Dysrhythmias IV: Characteristics of Bradyarrhythmias
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...
Dysrhythmias II: Classification of Tachyarrhythmias
Tachyarrhythmias are a type of dysrhythmia where the heart rate exceeds 100 beats per minute. Here are some common types of tachyarrhythmias:Sinus TachycardiaSinus tachycardia originates from increased impulses from the sinus node, leading to an elevated heart rate. It is often triggered by stress, fever, or exercise.Patients may experience palpitations, a sensation of a racing heart, dizziness, and chest discomfort.Causes and Risk Factors: Common causes include physical exertion, emotional...
Dysrhythmias III: Characteristics of Dysrhythmias
Dysrhythmias, also known as arrhythmias, are irregular heart rhythms that result from abnormal electrical activity in the heart, affecting its ability to circulate blood efficiently. Tachyarrhythmias, a subset of dysrhythmias, are characterized by abnormally fast heart rates exceeding 100 beats per minute. Here are some types of tachyarrhythmias with their distinct ECG features:Sinus Tachycardia:Sinus tachycardia presents a regular heart rhythm with an increased rate of 101-180 beats per minute.
Decreased pulse rate
Bradycardia is a medical condition in which the heart rate is slower than normal. It occurs when the heart's natural pacemaker, the sinus node, generates slower electrical impulses than the standard rhythm. In adults, bradycardia is diagnosed when the pulse rate falls below 60 beats per minute, indicating a deviation from the normal heart rate range.
There are specific risk factors that can elevate the likelihood of developing bradycardia. Advanced age is a significant factor, with bradycardia...
There are specific risk factors that can elevate the likelihood of developing bradycardia. Advanced age is a significant factor, with bradycardia...


