MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

ANATOMY, PHYSIOLOGY, PATHOLOGY

CHAPTER 5. BLOOD AND LYMPH CIRCULATION PROCESSES AND THEIR PATHOLOGY

CARDIOVASCULAR DISEASES

HEART FAILURE

1. ACUTE CIRCULATORY FAILURE

Sudden muscular failure of The Heart ventricles causes acute circulatory failure. Sudden cardiac weakness can result in death.

The MAIN CLINICAL MANIFESTATIONS of acute circulatory failure are cardiogenic Shock, cardiac asthma (interstitial pulmonary edema), and alveolar pulmonary edema.

Cardiogenic shock develops in ventricular fibrillation, paroxysmal tachycardia, myocardial infarction, and myocarditis. It is based on the impaired contractility of the left heart, resulting in insufficient Blood Filling of the Arterial System. In response to a smaller blood volume entering the vessels, a reflex release of catecholamines occurs, increasing peripheral resistance in the Vessels of the Skin, Muscles, and Internal Organs. Microcirculation is impaired, leading to organ Hypoxia and The Development of metabolic acidosis, which triggers cerebral ischemia with severe functional alterations, frequently accompanied by loss of consciousness and convulsions.

In cardiac asthma, the fluid component of the blood escapes from the pulmonary capillaries into the peribronchial and perivascular spaces. This impairs exchange conditions and contributes to increased resistance in the pulmonary vessels and Bronchi.

The penetration of the liquid part of the blood from the capillaries into the lung tissue can be caused by increased hydrostatic pressure in the Pulmonary Circulation due to left ventricular failure (aortic heart defects, diffuse cardiosclerosis, myocardial infarction). When the pressure in the pulmonary vessels exceeds a certain threshold (30 mmHg), active penetration of plasma into the pulmonary alveoli begins. Increased pressure in the pulmonary circulation vessels may also be caused by a sharp rise in pulmonary vascular resistance resulting from a mechanical obstruction to blood flow, such as in thromboembolism.

Further penetration of fluid from the vessels into the lung tissue leads to its accumulation in the alveolar lumen and the development of alveolar pulmonary edema. This is the most severe form of acute Heart Failure.