Main forms of valve dysfunction
The pathological process can damage the valve apparatus in two fundamentally different ways. Depending on the nature of structural changes, two basic types of dysfunction are distinguished.
- Stenosis (narrowing) of the orifice
This defect is based on the formation of pathological adhesions between the valve cusps. As a result, the valve does not open fully during the required phase of the cardiac cycle. Hemodynamically, this means the appearance of an obstruction to blood flow. The heart chamber that has to forcefully push and eject blood through a narrow orifice begins to experience tremendous pressure overload. Working in this enhanced mode, the muscle wall naturally thickens, leading to myocardial hypertrophy.
- Valve regurgitation (insufficiency)
In this case, the cusps lose the ability to tightly close the valve orifice. The causes of this condition are of two types:
- Organic insufficiency: the cusps themselves are physically destroyed by the process or shortened.
- Relative insufficiency: the cusps are completely healthy and unchanged, but due to significant stretching (dilatation) of the heart cavity itself, the fibrous ring of the valve expands greatly. As a result, the cusps simply cannot meet.
In insufficiency, the phenomenon of regurgitation occurs—the backward flow of blood during the phase when the valve should be tightly closed. In the next systole, the heart chamber has to accommodate not only its normal portion of blood, but also the entire volume that returned backward. Volume overload is formed, which leads to severe stretching and dilatation of the cardiac cavity.
Etiology and combined lesions
Rheumatism (rheumatic fever) is the most frequent cause of damage to intracardiac structures. The rheumatic process is insidious because it is often not limited to the formation of only one type of defect.
In clinical practice, doctors regularly encounter combined valvular disease, when both stenosis and insufficiency are simultaneously present on the same valve (the cusps neither can open fully nor are able to close tightly). The clinical presentation in such patients will depend on which of the defects predominates and impairs hemodynamics more severely at the given moment.
Diagnostic principles and stages
Auscultation remains the key tool for primary search and diagnosis. When a stream of blood is forcefully pushed through a narrowed ring (in stenosis) or flows back through a gap (in regurgitation), laminar flow is replaced by turbulent flow. It is these eddies that the physician hears as characteristic cardiac murmurs. In addition to the appearance of murmurs, heart valve defects predictably alter the heart sounds themselves.
The course of acquired valvular heart disease has a pronounced staging:
- In the initial stages, the clinical presentation is quite specific and strictly depends on which particular valve is affected.
- In the final stages, the clinical presentation becomes completely uniform. Regardless of which valve started the problem, compensatory mechanisms become exhausted, and the patient develops total heart failure encompassing both the systemic and pulmonary circulations.
Briefly: answers to topical questions
What is combined valvular heart disease and how does it differ from mixed (combined) lesions?
A combined valve defect is a pathology within a single valve characterized by simultaneous stenosis of the orifice and valve insufficiency. The main difference between these conditions lies in the number of involved valve structures.
| Type of defect | Characteristics of the lesion |
|---|---|
| Combined defect | Combination of stenosis and insufficiency on a single valve |
| Mixed defect | Involvement of two or more different valves |
The simultaneous presence of systolic and diastolic murmurs over the same orifice is often a diagnostic sign of a combined lesion.
Which diseases, other than rheumatic fever, can cause acquired heart defects?
In addition to rheumatic fever, degenerative, ischemic, and infectious processes can cause acquired heart defects.
The structure of etiological factors includes:
- Atherosclerosis — causes degenerative changes and calcification of the valve ring in the elderly.
- Infective endocarditis — leads to destruction of the valve apparatus and rupture of chordae.
- Coronary artery disease (CAD) and myocardial infarction — cause dysfunction or rupture of papillary muscles.
- Dilated cardiomyopathy and Marfan syndrome — lead to expansion of the fibrous ring and the formation of relative valve insufficiency.
Which heart valve is most frequently affected in rheumatic fever?
In rheumatic fever, the mitral valve is most frequently involved: the most common outcome of rheumatic endocarditis is the formation of mitral stenosis.
Mitral stenosis is often formed in combination with mitral regurgitation. When the aortic endocarditis occurs in a chronic course, mixed and combined defects can form.
What instrumental methods are used to confirm the diagnosis of a heart defect after auscultation?
For instrumental confirmation of a heart defect after auscultation, the sources indicate primarily imaging methods of the valve apparatus.
Instrumental studies used include:
- Echocardiography — the leading method for visualizing changes in the valve apparatus; transesophageal echocardiography is used for better visualization and diagnosis of valve pathology, especially in stenosis, as well as for verifying infective endocarditis by vegetations.
- Doppler echocardiography — allows assessment of hemodynamics: in mitral stenosis, the mitral orifice area, transmitral pressure gradient, and pulmonary artery pressure are measured; in tricuspid regurgitation, regurgitation through the tricuspid valve is visualized.
- M-mode echocardiography — used to analyze the movement of mitral valve cusps.
- Cardiac catheterization and angiocardiography — additional invasive methods for a more precise assessment of stenosis severity and intracardiac hemodynamics.
- In tricuspid insufficiency, ECG (signs of right ventricular hypertrophy and atrial fibrillation) and phlebogram (changes in venous pulse) are also indicated.
Remember the hemodynamic connection: Stenosis is Force (pressure overload) → leads to hypertrophy. Insufficiency is Volume (excess blood due to regurgitation) → leads to dilatation.
Class and exam questions
What is the difference between organic and relative insufficiency?
In organic insufficiency, the valve cusps themselves are destroyed or shortened. In relative insufficiency, the cusps are unchanged, but the fibrous ring is stretched due to significant enlargement of the heart chamber itself, so the cusps do not close.
Why do heart murmurs appear in valve diseases?
Murmurs occur due to turbulent (eddying) blood flow. This happens when blood either overcomes an anatomical obstacle in stenosis or is regurgitated back through an incompetent valve in insufficiency.
What does the term "combined valve disease" mean?
This is a pathological condition in which both orifice stenosis (adhesions) and insufficiency (inability to close) develop simultaneously on a single valve. Most often, this is a consequence of rheumatic fever.
What else to study on this topic
- Clinical presentation of the initial stages of specific acquired heart defects
- Specific changes in heart sounds in stenosis and insufficiency
- Mechanisms of heart failure formation in the systemic circulation
- Mechanisms of heart failure formation in the pulmonary circulation
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