まとめ
混沌とした心拍である心房細動は,非同期的な電気活動から生じる. それは特定の刺激によって開始され,興奮性心筋の質量を減らすことによって終了することができます.
科学分野:
- 心血管電気生理学 心血管電気生理学
- 心律不整症とは,心律不整症のことです.
背景:
- 心室細動 (VF) は,心室内の混沌とした非同期的な電気活動によって特徴付けられます.
- 静脈筋の固有の非均一な電気生理学的性質は,静脈筋を動に誘導する.
- 電気非同期性は,VFの発展と永続に決定的な役割を果たしています.
研究 の 目的:
- 室細動の開始,維持,および終了の基礎となる電気生理学的メカニズムをレビューする.
- この生命を脅かす不律の発症と解消に影響を与える要因を解明する.
主な方法:
- 静脈細動の電気生理学に関する既存の文献のレビュー.
- リエントラント刺激と焦点放電に関連するメカニズムの分析.
- 電気シンクロニーと心房筋の性質に影響する要因の検討.
主要な成果:
- VFは,脆弱な期間の刺激または急速な心房回転率によって開始することができます.
- VFの永続は,大きな刺激性心室質量,短い耐火期,そして遅い伝導によって好まれる.
- VFの終結は,興奮可能な心室質量が自発的な動に必要な値を下回ったときに起こります.
結論:
- 静脈細動は静脈筋の固有の性質であり,電気的アシンクロニーによって促進される.
- 特定の条件と電気生理学的パラメータは,VFの開始,維持,終了に不可欠です.
- VFを終了するには,すべての心房細胞の完全な脱極化を必要としません.
関連する概念動画
The Cardiac Cycle
The heart beats rhythmically in a sequence called the cardiac cycle—a rapid coordination of contraction (systole) and relaxation (diastole).
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and empty blood into the...
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and empty blood into the...
Electrophysiology of Normal Cardiac Rhythm
The normal cardiac rhythm is a synchronized electrical activity that facilitates the regular and coordinated contraction of the heart muscle. This process is essential for efficient blood circulation throughout the body. The fundamental elements involved in establishing and maintaining this rhythm include the unique electrical properties of cardiac muscle cells, the sinoatrial (SA) node's pacemaker function, the specialized conducting system, and the ionic mechanisms underlying each phase of...
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.
Heart Valves
The human heart is a complex organ with an intricate system of valves that regulate blood flow. There are two main types of valves: atrioventricular (AV) valves and semilunar valves.
The AV valves prevent the backflow of blood from the ventricles to the atria during ventricular contraction. These valves function with the assistance of the chordae tendineae and papillary muscles. When the ventricles are relaxed, the chordae tendineae are slack, allowing blood to flow from the atria into the...
The AV valves prevent the backflow of blood from the ventricles to the atria during ventricular contraction. These valves function with the assistance of the chordae tendineae and papillary muscles. When the ventricles are relaxed, the chordae tendineae are slack, allowing blood to flow from the atria into the...
Conduction System of the Heart
Autorhythmicity is a term that refers to the heart's inherent ability to generate electrical signals and instigate muscle contractions. This self-regulating conduction system within the heart consists of two key components: the pacemaker cells and specialized conducting cells.
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
Conduction System of the Heart
The cardiac conduction system produces and transmits electrical impulses that prompt myocardial contraction, ensuring efficient heart function. This intricate system ensures that the heart beats in a coordinated and efficient manner, beginning with the atria and then the ventricles. The conduction system optimizes cardiac output by maintaining this precise sequence, which is crucial for adequate blood circulation.
This system relies on the unique properties of nodal and Purkinje cells:...
This system relies on the unique properties of nodal and Purkinje cells:...


