慢性的な体積過負荷の廃止. フォンタン修復直後の全身性心室のダイアストリック機能への影響
M Gewillig1, W Daenen, A Aubert
1Laboratory of Experimental Cardiology, O/N Gasthuisberg, University of Leuven, Belgium.
Circulation
|November 1, 1992
まとめ
フォンタン回路の形成後,心室壁の厚さが増加すると,粘度と惰性による早期の腹動脈充填が損なわれ,リラックスが損なわれない. 静脈の吸い込みは減るが,リラックス性は時間とともに回復する.
科学分野:
- 心臓病学 心臓病学
- ペディアトリック・カルディオロジー
- 心臓外科手術について
背景:
- 単心室の心臓を持つ患者は,慢性的な心室の体積過負荷を廃止するために,フォンタンの回路作成を受けます.
- この手法は心室腔のサイズを小さくしますが,手術後の心室壁の不適切な加厚につながる可能性があります.
- 静脈のダイアストリック特性への影響は,まだ十分に理解されていない.
研究 の 目的:
- 慢性的な体積過負荷の急性除去後の心室のダイアストリック特性を調査する.
- 腹腔壁の厚さの増加がリラクゼーションや早期充填を妨げているかどうかを判断する.
主な方法:
- 改造されたブラロック-タウシグシャントを使用して,混血犬で慢性的な体積過負荷モデルが作成されました.
- シャントは皮膚経由で遮断され,左心室の寸法と壁の厚さはエコーカルディオグラフィを使用して測定されました.
- 同体圧の衰退 (tau),同体圧のリラックス時間 (A2-MVO),最小左心室圧 (A2-LVPmin) までの時間を記録した.
主要な成果:
- 閉塞後1時間後,左心室の寸法は,基礎線への不完全な戻りを示し,後部壁の厚さが増加しました.
- Ventricular relaxation (tau) は変化しなかったが,早期の充填は鈍化し, Ventricular suction (心室吸い込み) の低下を示した.
- A2-MVOとA2-LVPminは,シャント閉塞後の最大1週間にわたって有意に増加しました.
結論:
- ボリュームオーバーロードの除去後早期に,壁の厚さが増加しても,心室のリラックスが損なわれません.
- 増加した質量比による粘度と慣性により,早期の心室充填が損なわれます.
- 容量誘発性高縮症は1ヶ月で回復し,早期心室充填指数が回復しました.
関連する概念動画
01:29Cardiac Cycle
The cardiac cycle refers to the sequence of events that occur in the heart from the beginning of one heartbeat to the next. It's characterized by alternating periods of contraction (systole) and relaxation (diastole) of the heart muscles.
During the cardiac cycle, blood flow through the heart is regulated entirely by changing pressure gradients. This sequence of events begins with the heart in a state of total relaxation, known as mid-to-late diastole, during which blood passively flows from...
During the cardiac cycle, blood flow through the heart is regulated entirely by changing pressure gradients. This sequence of events begins with the heart in a state of total relaxation, known as mid-to-late diastole, during which blood passively flows from...
01:26Imbalances in Cardiac Output
The heart's primary function is to pump blood throughout the body, maintaining a balance between blood sent out (cardiac output) and blood returning (venous return). If this balance is disrupted, it can result in congestive heart failure (CHF), a severe condition where the heart becomes an inefficient pump, leading to inadequate blood circulation.
CHF can occur due to the failure of either side of the heart. Left-side failure leads to pulmonary congestion—the right side continues to send blood...
CHF can occur due to the failure of either side of the heart. Left-side failure leads to pulmonary congestion—the right side continues to send blood...
01:20Mitral Regurgitation I: Introduction
Mitral regurgitation is characterized by the backward circulation of blood from the left ventricle to the left atrium during systole, a phase of the cardiac cycle when the heart contracts and pumps blood out of the chambers. This abnormal flow occurs primarily due to the dysfunction of the mitral valve or its supporting structures, which include the mitral leaflets, chordae tendineae, annulus, and papillary muscles.Etiology and Mechanisms:Primary Mitral Regurgitation: This type arises from...
01:22Mitral Stenosis I: Introduction
Mitral Valve Stenosis (MVS) is a heart condition where the mitral valve narrows, impeding blood circulation from the left atrium to the left ventricle. The etiology and pathophysiology of this condition are multifaceted, leading to a cascade of cardiovascular complications.Causes of Mitral Valve StenosisRheumatic Heart Disease: It is the main cause of mitral valve stenosis, particularly in developing nations. This condition arises from rheumatic fever, an inflammatory illness resulting from...
01:15Aortic Regurgitation I: Introduction
IntroductionAortic regurgitation is characterized by the backward flow of blood from the aorta into the left ventricle during diastole and arises from the improper closure of the aortic valve. This condition results in left ventricular volume overload and can stem from both acute and chronic etiologies, each contributing uniquely to the disease's progression and symptomatology.Acute and Chronic CausesAcute aortic regurgitation often results from events that suddenly impair the integrity of the...
01:29Heart Failure II: Pathophysiology
Systolic Heart Failure and Compensatory MechanismsSystolic heart failure (also termed HFrEF, Heart Failure with Reduced Ejection Fraction) is the most prevalent type of heart filure. It results in a decreased volume of blood being pumped from the ventricle. The aortic arch and carotid sinuses have baroreceptors that detect reduced blood pressure, triggering the sympathetic nervous system (SNS) to release epinephrine and norepinephrine. Initially, this response aims to boost heart rate and...