有趣的电流下调和节功能障碍与心房动脉节律失调有关:心动节律失调 - 心拍综合征的分子基础
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
概括
耳前动脉节律失常 (ATs) 通过减少关键离子通道表达,特别是有趣电流 (I(f)) 来损害耳前节点 (SAN) 功能. 这种离子通道重塑有助于SAN功能障碍和相关心律失常.
科学领域:
- 心脏病学 心脏病学
- 电子生理学 电子生理学
- 分子生物学分子生物学
背景情况:
- 阴心节点 (SAN) 功能障碍通常与心房动脉节律失常 (ATs) 有关.
- 后AT SAN功能障碍可能导致昏迷,并需要心脏起器植入.
- 在AT诱导的SAN功能障碍背后的机制尚未完全理解.
研究的目的:
- 为了调查AT是否通过改变离子通道表达来损害SAN功能.
- 识别受ATS影响的特定离子通道和子单元.
- 为了将离子通道表达的变化与SAN细胞中的功能缺陷相关联.
主要方法:
- 从对照犬和接受了为期7天的心房高血压减速治疗的狗身上收集了SAN组织.
- 整个细胞补丁技术被用来测量单个SAN细胞中的离子电流.
- 实时逆转录聚合酶链反应 (RT-PCR) 量化了关键离子通道子单元的mRNA表达.
主要成果:
- 耳前电动阻隔显著增加了SAN恢复时间,表明功能受损.
- HCN2,HCN4和minK亚单元的表达在快节奏SAN中显著减少.
- 滑稽电流 (I(f)) 和缓慢的延迟校正电流 (I(Ks)) 的密度减少,I(f) 变化主要解释了SAN周期性的减缓.
- 其他关键通道 (I ((Kr),I ((Ks),I ((CaL),I ((CaT),连xin 43) 的表达没有受到影响.
结论:
- 耳前动脉节律失常会降低SAN HCN2/4和minK亚单元的表达.
- 这导致I(f) 和I(Ks) 电流减少,导致SAN功能障碍.
- 动脉动引起的SAN离子通道重塑,特别是I{\displaystyle I}f,是AT和SAN功能障碍之间的关键因素.
相关概念视频
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...


