心脏病理学

.源自文库•
Anything that may affect the heart rate, stroke volume, and ejection fraction, may lead to the heart pumping less efficiently. This can cause blood to back up into the veins leading to the heart, increasing pressure within the capillaries, the smallest of blood vessels in the body and in turn cause water (fluid) to leak into the interstitial space (the space between cells that make up the tissue and organs of the body). • Consequently, ↓cardiac output results in → ↑pressure in capillary blood vessels→ water leaking→ heart failure symptoms
Cardiac output = stroke volume X heart rate (beats per minute)
NORMAL FOR MALE IS ABOUT 5.5 LITERS OF BLOOD PUMPED BY THE HEART TO THE BODY EVERY MINUTE
Left Sided CHF:
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The 4 primary determinants of left ventricular (LV) performance are generally altered as follows: (1) There is an intrinsic decrease in muscle contractility. (2) Preload or left atrial filling pressure is increased, resulting in pulmonary congestion and dyspnea.
Cardiac Pathophysiology
A Short Overview
1. The Pathophysiology of Congestive Heart Failure (CHF)
Congestive heart failure is a syndrome that can be caused by a variety of abnormalities, including: • Pressure and volume overload, • loss of muscle, • primary muscle disease or • excessive peripheral demands such as high output failure.
NORMAL FOR FEMALE IS ABOUT 5.0 LITERS PER MINUTE
Left and Right-Sided CHF:
. • Left heart failure occurs when the left ventricle cannot pump blood to the body and fluid backs up and leaks into the lungs causing shortness of breath.
The Pathophysiology of CHF
The main causes of heart failure are: atherosclerosis (calcification of the arteries), hypertension or coronary artery disease (due to calcification of the arteries). Other diseases affecting the myocardium or heart valves can cause heart failure : • Myocardial inflammation, myocarditis • Valve disease, endocarditis • Heart rhythm disorders • Pneumonia • Pericardial effusion (pericarditis) or narrowing of the pericardium • Hyperfunction of the thyroid, hyperthyroidism • Heart disease, congenital or acquired • Family history
In the usual form of heart failure, the heart muscle has reduced contractility. This produces a reduction in cardiac output, which then becomes inadequate to meet the peripheral demands of the body.
• Right heart failure occurs when the right ventricle cannot adequately pump blood to the lungs. Blood and fluid may back up in the veins that deliver blood to the heart. This can cause fluid to leak into tissues and organs.