Mitral heart defects. Ethyology. Pathogenesis. Clinical pattern. Diagnostics. Treatment. Prophylaxis. Role of a doctor- dentist in prophylaxis.

Aortic heart defects. Ethyology. Pathogenesis. Clinical pattern. Diagnostics. Treatment. Prophylaxis. Role of a doctor- dentist in prophylaxis.

 

Heart Valvular Disease

Stable pathological changes in the structure of the heart that interfere with its normal function are called heart valvular disease. Congenital and acquired diseases of the heart valves are distinguished. The incidence of acquired heart diseases is much higher.

The structure of the heart

 

Primary valvular heart disease ranks well below coronary heart disease, stroke, hypertension, obesity, and diabetes as major threats to the public health. Nevertheless, it is the source of significant morbidity and mortality. Rheumatic fever is the dominant cause of valvular heart disease in developing countries. Its prevalence has been estimated to range from as low as 1.0 per 100,000 school-age children in Costa Rica to as high as 150 per 100,000 in China. Rheumatic heart disease accounts for 12–65% of hospital admissions related to cardiovascular disease and 2–10% of hospital discharges in some developing countries. Prevalence and mortality rates vary among communities even within the same country as a function of crowding and the availability of medical resources and population-wide programs for detection and treatment of Group A streptococcal pharyngitis. In economically deprived areas, tropical and subtropical climates (particularly on the Indian subcontinent), Central America, and the Middle East, rheumatic valvular disease progresses more rapidly than in more-developed nations and frequently causes serious symptoms in patients <20 years of age. This accelerated natural history may be due to repeated infections with more virulent strains of rheumatogenic streptococci. TS, a relatively uncommon valvular lesion in North America and Western Europe, is more common in tropical and subtropical climates, especially in southern Asia and in Latin America.

As of the year 2000, worldwide death rates for rheumatic heart disease approximated 5.5 per 100,000 population (n = 332,000), with the highest rates reported from Southeast Asia. Although there have been reports of recent isolated outbreaks of streptococcal infection in North America, valve disease in developed countries is now dominated by degenerative or inflammatory processes that lead to valve thickening, calcification, and dysfunction. The prevalence of valvular heart disease increases with age. Important left-sided valve disease may affect as many as 12–13% of adults over the age of 75.

The incidence of infective endocarditis has increased with the aging of the population, the more widespread prevalence of vascular grafts and intracardiac devices, the emergence of more virulent multidrug-resistant microorganisms, and the growing epidemic of diabetes. Infective endocarditis has become a more frequent cause of acute valvular regurgitation.

Bicuspid aortic valve disease affects as many as 1–2% of the population, and an increasing number of childhood survivors of congenital heart disease present later in life with valvular dysfunction. The past several years have witnessed significant improvements in surgical outcomes with progressive refinement of relatively less-invasive techniques. Percutaneous heart valve replacement or repair is under active clinical investigation.

 

 

Congenital diseases of the heart arise due to abnormal development of the heart and the great vessels during the intrauterine growth of the foetus with preservation of the intrauterine character of circulation after birth. In defective division of the primary single-chamber arterial trunk into the pulmonary trunk and the aorta, and during formation of the heart chambers, defects in the interatrial and interventricular septa may be formed along with various abnormalities in the arrangement of the great vessels and their narrowing. Preservation of the intrauterine character of circulation after birth is the cause of patent ductus arteriosus (Botallo’s duct) and patent foramen ovale. Congenital heart defects may often combine with communicated greater and lesser circulation systems and stenosis of the great vessels. Moreover, the valves (bicuspid, tricuspid, aortic, and pulmonary valves) may also have congenital defects.

 Endocarditis, and especially rheumatic endocarditis, is the main cause of acquired heart defects. Less frequently heart disease is the result of sepsis, atherosclerosis, syphilis, injuries, etc. Inflammatory processes occurring in the valve cusps often end in their sclerosis, deformation and shortening. An affected valve does not close completely to cause valvular incompetence. The cusps of the valves may adhere to one another because of inflammation to narrow the orifice they close. This narrowing is called stenosis.

Valvular heart disease

Valvular heart disease is any disease process involving one or more of the valves of the heart (the aortic and mitral valves on the left and the pulmonary and tricuspid valves on the right). Valve problems may be congenital (inborn) or acquired (due to another cause later in life). Treatment may be with medication but often (depending on the severity) involves valve repair or replacement (insertion of an artificial heart valve). Specific situations include those where additional demands are made on the circulation, such as in pregnancy.

Types

Valve involved	Stenotic disease	Insufficiency/regurgitation disease
Aortic valve	Aortic valve stenosis	Aortic insufficiency/regurgitation
Mitral valve	Mitral valve stenosis	Mitral insufficiency/regurgitation
Tricuspid valve	Tricuspid valve stenosis	Tricuspid insufficiency/regurgitation
Pulmonary valve	Pulmonary valve stenosis	Pulmonary insufficiency/regurgitation

Aortic and mitral valve disorders

Pulmonary and tricuspid valve disorders

Pulmonary and tricuspid valve diseases are right-side heart diseases. Pulmonary valve diseases are the least common heart valve disease in adults.

The most common types of pulmonary valve diseases are:

• pulmonary valve stenosis
• pulmonary valve insufficiency
• pulmonary valve incompetence
• pulmonary valve regurgitation

Both tricuspid and pulmonary valve diseases are less common than aortic or mitral valve diseases due to the lower pressure those valves experience.

Dysplasia

Heart valve dysplasia is an error in the development of any of the heart valves, and a common cause of congenital heart defects in humans as well as animals; tetralogy of Fallot is a congenital heart defect with four abnormalities, one of which is stenosis of the pulmonary valve. Ebstein’s anomaly is an abnormality of the tricuspid valve.

Rheumatic disorders

Valvular heart disease resulting from rheumatic fever is referred to as “rheumatic heart disease”. While developed countries once had a significant burden of rheumatic fever and rheumatic heart disease, medical advances and improved social conditions have dramatically reduced their incidence. Many developing countries, as well as indigenous populations within developed countries, still carry a significant burden of rheumatic fever and rheumatic heart disease and there has been a resurgence in efforts to eradicate the diseases in these populations. Inflammation of the heart valves due to any cause is called endocarditis; this is usually due to bacterial infection but may also be due to cancer (marantic endocarditis), certain autoimmune conditions (Libman-Sacks endocarditis) and hypereosinophilic syndrome (Loeffler endocarditis). Certain medications have been associated with valvular heart disease, most prominently ergotamine derivatives pergolide and cabergoline.

In pregnancy

The evaluation of individuals with valvular heart disease who are or wish to become pregnant is a difficult issue. Issues that have to be addressed include the risks during pregnancy to the mother and the developing fetus. Normal physiological changes during pregnancy require, on average, a 50% increase in circulating blood volume that is accompanied by an increase in cardiac output that usually peaks between the midportion of the second and third trimesters. The increased cardiac output is due to an increase in the stroke volume, and a small increase in heart rate, averaging 10 to 20 beats per minute.^[4] Additionally uterine circulation and endogenous hormones cause systemic vascular resistance to decrease and a disproportionately lowering of diastolic blood pressure causes a wide pulse pressure. Inferior vena caval obstruction from a gravid uterus in the supine position can result in an abrupt decrease in cardiac preload, which leads to hypotension with weakness and lightheadedness. During labor and delivery cardiac output increases more in part due to the associated anxiety and pain, as well as due to uterine contractions which will cause an increases in systolic and diastolic blood pressure. Valvular heart lesions associated with high maternal and fetal risk during pregnancy.

1. Severe aortic stenosis with or without symptoms

 2. Aortic regurgitation with NYHA functional class III-IV symptoms

 3. Mitral stenosis with NYHA functional class II-IV symptoms

 4. Mitral regurgitation with NYHA functional class III-IV symptoms

 5. Aortic and/or mitral valve disease resulting in severe pulmonary hypertension (pulmonary pressure greater than 75% of systemic pressures)

 6. Aortic and/or mitral valve disease with severe LV dysfunction (EF less than 0.40)

 7. Mechanical prosthetic valve requiring anticoagulation 8. Marfan syndrome with or without aortic regurgitation

In individuals who require an artificial heart valve, consideration must be made for deterioration of the valve over time (for bioprosthetic valves) versus the risks of anticoagulation during pregnancy.

Comparison

            The following table includes the main types of valvular stenosis and regurgitation. Major types of valvular heart disease not included in the table include mitral valve prolapse, rheumatic heart disease and endocarditis.

Valvular disease	Mitral stenosis	Aortic stenosis	Aortic regurgitation	Mitral regurgitation	Tricuspid regurgitation
Prevalence	Most common valvular heart disease in pregnancy[5]	Approximately 2% of people over the age of 65, 3% of people over age 75, and 4% percent of people over age 85[6]		2% of the population, equally in males and females.[7]
Main causes and risk factors	Almost always caused by rheumatic heart disease	Calcification of tricuspid aortic valve with age (>50%) Calcification of bicuspid aortic valve (30-40%) Rheumatic fever (<10%) Hypertension, diabetes mellitus, hyperlipoproteinemia and uremia may speed up the process.	Acute Infective endocarditis Trauma Chronic Primary valvular: rheumatic fever, bicuspid aortic valve, Marfan‘s syndrome, Ehlers–Danlos syndrome, ankylosing spondylitis, systemic lupus erythematosus Disease of the aortic root: syphilitic aortitis, osteogenesis imperfecta, aortic dissection, Behçet’s disease, reactive arthritis, systemic hypertension	Acute Endocarditis, mainly S. aureus Papillary muscle rupture or dysfunction, including mitral valve prolapse Chronic Rheumatic fever Marfan’s syndrome Cardiomyopathy	Usually secondary to right ventricular dilation left ventricular failure is, in turn, the most common cause Right ventricular infarction Inferior myocardial infarction Cor pulmonale Other causes: Tricuspid endocarditis, rheumatic fever, Ebstein’s anomaly, carcinoid syndrome and myxomatous degeneration
Hemo dynamics / Patho- physiology	Progressive obstruction of the mitral ostium causes increased pressure in the left atrium and the pulmonary circulation. Congestion may cause thromboembolism, and atrial hypertension may cause atrial fibrillation.	Obstruction through the aortic ostium causes increased pressure in the left ventricle and impaired flow through the aorta	Insufficiency of the aortic valve causes backflow of blood into the left ventricle during diastole.	Insufficiency of the mitral valve causes backflow of blood into the left atrium during systole.	Insufficiency of the tricuspid valve causes backflow of blood into the right atrium during systole.
Symptoms	Heart failure symptoms, such as dyspnea on exertion, orthopnea and paroxysmal nocturnal dyspnea Palpitations Chest pain Hemoptysis Thromboembolism Ascites and edema (if right-sided heart failure develops) Symptoms increase with exercise and pregnancy	Heart failure symptoms, such as dyspnea on exertion (most frequent symptom), orthopnea and paroxysmal nocturnal dyspnea Angina pectoris Syncope, usually exertional	Heart failure symptoms, such as dyspnea on exertion, orthopnea and paroxysmal nocturnal dyspnea Palpitations Angina pectoris In acute cases: cyanosis and circulatory shock	Heart failure symptoms, such as dyspnea on exertion, orthopnea and paroxysmal nocturnal dyspnea Palpitations Pulmonary edema	Symptoms of right-sided heart failure, such as ascites, hepatomegaly, edema and jugular venous distension
Medical signs	Opening snap followed by a low-pitched diastolic rumble with presystolic accentuation. The opening snap follows closer to the S2 heart tone with worsening stenosis. The murmur is heard best with the bell of the stethoscope lying on the left side and its duration increases with worsening disease. Loud S1 – may be the most prominent sign Advanced disease may present with signs of right-sided heart failure such as parasternal heave, jugular venous distension, hepatomegaly, ascites and/or pulmonary hypertension (presenting with a loud P2. Signs increase with exercise and pregnancy	Systolic murmur of a harsh crescendo-decrescendo type, heard in 2nd right intercostal space, radiating to the carotid arteries Pulsus parvus et tardus, that is, diminished and delayed carotid pulse Fourth heart sound Decreased A2 sound Sustained apex beat Precordial thrill	Increased pulse pressure by increased systolic and decreased diastolic blood pressure, but may not be significant if acute Diastolic decrescendo murmur best heard at left sternal border Water hammer pulse Austin Flint murmur Apex beat displaced down and to the left Third heart sound may be present	Holosystolic murmur at the apex, radiating to the back or clavicular area Commonly atrial fibrillation Third heart sound Laterally displaced apex beat, often with heave Loud, palpable P2, heard best when lying on the left side In acute cases, the murmur and tachycardia may be only distinctive signs.	Pulsatile liver Prominent V waves and rapid y descents in jugular venous pressure Inspiratory third heart sound at left lower sternal border (LLSB) Blowing holosystolic murmur at LLSB, intensifying with inspiration, and decreasing with expiration and Valsalva maneuver Parasternal heave along LLSB Atrial fibrillation is usually present
Diagnosis	Chest X-ray showing left atrial enlargement Echocardiography is the most important test to confirm the diagnosis. It shows left atrial enlargement, thick and calcified mitral valve with narrow and “fish-mouth”-shaped orifice and signs of right ventricular failure in advanced disease	Chest X-ray showing calcific aortic valve, and in longstanding disease, enlarged left ventricle and atrium ECG showing left ventricular hypertrophy and left atrial abnormality Echocardiography is diagnostic in most cases, showing left ventricular hyperthrophy, thickened and immobile aortic valve and dilated aortic root, but may appear normal if acute Cardiac chamber catheterization provides a definitive diagnosis, indicating severe stenosis in valve area of <0.8 cm2 (normally 3 to 4 cm2). It is useful in symptomatic patients before surgery.	Chest X-ray showing left ventricular hypertrophy and dilated aorta ECG indicating left ventricular hypertrophy Echocardiogram showing dilated left aortic root and reversal of blood flow in the aorta. In longstanding disease there may be left ventricular dilatation. In acute aortic regurgitation, there may be early closure of the mitral valve. Cardiac chamber catetherization assists in assessing the severity of regurgitation and any left ventricular dysfunction	Chest X-ray showing dilated left ventricle Echocardiography to detect mitral reverse flow, dilated left atrium and ventricle and decreased left ventricular function	Echocardiography identifying tricuspid prolapse or flail ECG showing enlargement of right ventricle and atrium
Treatment	No therapy is required for asymptomatic patients. Diuretics for any pulmonary congestion or edema. If stenosis is severe, surgery is recommended. Any atrial fibrillation is treated accordingly. Medically, with diuretics, prophylaxis of infective endocarditis and chronic anticoagulant administration with warfarin (especially when there’s atrial fibrillation) Surgically, by mitral valvuloplasty with a percutaneously inserted balloon, unless significant mitral regurgitation or too much calcification. Indicated in ostium area < 1-1.2 cm2. Other options include valvulotomy or mitral valve replacement by open surgery	No treatment in asymptomatic patients. If symptomatic, treated with aortic valve replacement surgery. Medical therapy and percutaneous balloon valvuloplasty have relatively poor effect. – Any angina is treated with short-acting nitrovasodilators, beta-blockers and/or calcium blockers – Any hypertension is treated aggressively, but caution must be taken in administering beta-blockers – Any heart failure is treated with digoxin, diuretics, nitrovasodilators and, if not contraindicated, cautious inpatient administration of ACE inhibitors	If stable and asymptomatic – conservative treatment such as low sodium diet, diuretics, vasodilators (e.g. (hydralazin or prazosin), digoxin, ACE inhibitors/angiotensin II receptor antagonists , calcium blockers and avoiding very strenuous activity Aortic valve replacement in symptomatic patients (NYHA II-IV) or progressive left ventricular dilation or systolic ventricular diameter >55 mm on echocardiogrphy. Immediately if acute. Also, endocarditis prophylaxis is indicated before dental, gastrointestinal or genitourinary procedures.	Medically Afterload reduction with vasodilators Any hypertension is treated aggressively, e.g. by diuretics and low sodium diet digoxin Antiarrhythmics Chronic anticoagulation in concomitant mitral valve prolapse or atrial fibrillation In acute cases – IABP as temporary solution until surgery Surgery by either mitral valve repair or mitral valve replacement, indicated if very symptomatic (NYHA III), ventricular dilation or decreasing ejection fraction	Treatment of underlying cause Surgery Tricuspid valvular repair Valvuloplasty Valve replacement (rarely performed)
Follow-up		In moderate cases, echocardiography every 1–2 years, possibly complemented with cardiac stress test. Immediate revisit if new related symptoms appear. In severe cases, echocardiography every 3–6 months. Immediate revisit or inpatient care if new related symptoms appear.	In mild to moderate cases, echocardiography and cardiac stress test every 1–2 years In severe moderate/severe cases, echocardiography with cardiac stress test and/or isotope perfusion imaging every 3–6 months.	In mild to moderate cases, echocardiography and cardiac stress test every 1–3 years. In severe cases, echocardiography every 3–6 months.

 

 

MITRAL INCOMPETENCE

       Incompetence of the mitral (bicuspid) valve (mitral insufficiency) is incomplete closure of the atrioventricular orifice during left-ventricular systole. As a result, the blood is regurgitated from the ventricle back to the atrium. Mitral incompetence may be organic and functional.

       Organic insufficiency arises as a result of rheumatic endocarditis. Connective tissue develops in the cusps of the mitral valve which then contracts to shorten the cusps and the tendons. The edges of the affected valve do not meet during systole and part of the blood is regurgitated through the slit into the left atrium from the ventricle during its contraction.

     In functional (relative) incompetence the mitral valve is not altered but the orifice, which it  has to close, is enlarged and the cusps fail to close it completely. Functional incomenetcei of the mitral valve may develop because of dilatation of the left ventricle (in myocarditis, myocardial dystrophy, or cardiosclerosis) and weakening of the circular muscle fibers that  form the ring round the atrioventricular orifice. Affection of papillary muscles mav also cause functional mitral incompetence. Functional insufficiency thus depends on dysfunction of the  muscles responsible for the closure of the valve.

            Haemodynamics. If the mitral valve fails to close completely during systole of the left ventricle, part of the blood is regurgitated into the left atrium. Blood filling of the atrium thus increases (because of the blood from the pulmonary veins which is added to the normal blood volume. Pressure in the left atrium increases, the atrium is dilated and becomed hypertrophied.

The amount of blood that is delivered into the left ventricle frpm the overfilled left atrium during diastole exceeds normal and the atrium is thus overfilled and distended. The left ventricle has to perform excess work and becomes hypertrophied. Intensified work of the left ventricle compensates for the mitral incompetence during a long time. When thw contractile power of the left ventricular myocardium weakens, distolic pressure in it increases and this in turn increases pressure in the left atrium.

             Increased pressure in the left atrium increases pressure in the pulmonary veins and this in turn causes reflex contraction of the arterioles in the lesser circulation (Kitaev’s reflex) due to stimulation of baroreceptors. Spasm  in the arterioles increases significantly pressure in the pulmonary artery to intensify the load on the right ventricle which has to contact with a greater force in order to eject blood into the pulmonary trunk. The right ventricle can therefore also be hypertrophied during long-standing pronounced mitral incompetence.

 

Causes and mechanisms of mitral regurgitation

 

Schematic anatomical mitral-valve presentation

 

          Clinical picture. Most patients with mild or moderate mitral incompetence have no complaints for a long time and look very much like healthy subjects.  As congestion in the lesser circulation develops, dyspnoea,  palpitation of the heart, cyanosis, and other symptoms appear.

Appearance of the patient with mitral incompetence

 

          Palpation of the heart area reveals displacement of the apex beat to the left, sometimes inferiorly. The beat becomes diffuse, intensified, and resistant, which indicates hypertrophy of the left ventricle. Percussion reveals displacement of the heart’s borders to the left and superiorly because of the enlarged left atrium and left ventricle. The configuration of the heart becomes mitral with an indistinct heart waist. The border of the heart shifts to the right in hypertrophy of the right ventricle. Auscultation I the heart reveals decreased first sound at the heart apex because the valves never close completely in this disease. Systolic murmur can be heard at the same point, which is the main sign of mitral incompetence. It arises during systole when the stream of blood passes a narrow slit leading from the left ventricle to the left atrium. The systolic murmur is synchronous with the first sound. When the blood pressure rises in the lesser circulation, an accent of the second sound can be heard over the pulmonary trunk.

        Auscultation findings are confirmed and verified by phonocardiography. The pulse and arterial pressure do not change in compensated mitral incompetence.

        X-ray studies show a specific enlargement of the left atrium and the left ventricle detectable by eniarg^ement (to the left, superiorly and posteriorly) of the heart silhouette. When blood, pressure increases in the lesser circulation, the pulmoafry arcn dilates.

        Signs of hypertrophy of the left atrium and the left ventricle can also be found on the ECG: it becomes the left type and the P waves become higher.

        Echocardiography reveals distention of the left heart chambers (atrium and ventricle), movement of the mitral valve cusps in the opposite direction, their thickening and the absence of full closure during systole.   

 

 

 

            Doppler echocardiography is the main method for assessment of patients with mitral regurgitation. Transthoracic or transoesophageal echocardiography provides functional anatomical information that is crucial for assessment of reparability by defining cause, mechanism, presence of calcification, and localisation of lesions. Transoesophageal echocardiography provides better imaging quality than transthoracic echocardiography but its ability to detect details such as ruptured chordae rarely changes management. Transoesophageal echocardiography essentially provides incremental clinically meaningful information (such as reparability) when transthoracic echocardiography is of poor quality or when complex, calcified, or endocarditic lesions are suspected. Thus, transoesophageal echocardiography is rarely used on an outpatient basis and is mostly used intraoperatively for lesion verification and to monitor surgical results. Real-time three-dimensional echocardiography has at present insufficient image resolution but pilot data suggest that it allows quantitative assessment of structures that are not easily measurable by two-dimensional echocardiography, such as mitral annulus. Although emerging technologies such as transoesophageal echocardiography three-dimensional imaging have great potential, they need to be rigorously tested.

            Doppler echocardiography provides crucial information about mitral regurgitation severity Comprehensive integration of colour-flow imaging and pulsed and continuous wave doppler echocardiography is necessary because jet-based assessment has major limitations. Quantitative assessment of regurgitation is feasible by three methods—quantitative doppler echocardiography based on mitral and aortic stroke volumes, quantitative two-dimensional echocardiography based on left-ventricular volumes, and flow-convergence analysis measuring flow with colour-flow imaging proximal to the regurgitant orifice (proximal isovelocity surface area method; figure ). These methods allow measurement of ERO area and RVol and have important prognostic value. Severe mitral regurgitation is diagnosed with an ERO area of at least 40 mm2 and RVol of at least 60 mL per beat; and moderate regurgitation with ERO area 20—39 mm2 and RVol 30—59 mL per beat. Outcome data suggest that a smaller volume mitral regurgitation and smaller ERO area (≥30 mL and ≥20 mm2, respectively) are associated with severe outcome in patients with ischaemic disease; therefore, thresholds for severe disease are cause-dependent. Consistency in all measures of mitral regurgitation severity is essential to appropriately grade disease severity (table ). Haemodynamic assessment is completed with doppler measurement of cardiac index and pulmonary pressure.

 

            Gradation of mitral regurgitation by doppler echocardiography

            Modified from Zoghbi and colleagues.5 ERO=effective regurgitant orifice area. LA=left atrium. LV=left ventricle. MR=mitral regurgitation. RF=regurgitant fraction. RVol=regurgitant volume.

 

 

 

Use of colour-flow imaging for assessment of mitral regurgitation

 

            Doppler echocardiography also measures left-ventricular and left-atrial consequences of mitral regurgitation. End-diastolic left-ventricular diameter and volume indicate volume overload whereas end-systolic dimension shows volume overload and ventricular function. Patients with left-ventricular ejection fraction less than 60% or end-systolic diameter of at least 40—45 mm are regarded as having overt left-ventricular dysfunction. Left-atrial diameter indicates volume overload but also conveys important prognostic information. Left-atrial volume was recommended as the preferred measure of atrial overload, (at least 40 mL/m2 for severe dilatation) and predicts the occurrence of atrial fibrillation.

 

 

X-ray in mitral incompetence. Mitral heart configuration

 

Ultrasound picture of mitral incompetence. Enlarged left ventricle and atrium

 

            Mitral incompetence may remain compensated for a long time. But a long-standing pronounced mitral incompetence and decreased myocardial contractility of the left atrium and the left ventricle cause venous congestion in the lesser circulation. Contractility of the right ventricle can later be affected with subsequent development of congestion in the greater circulation.

STENOSIS OF THE LEFT ATRIOVENTRICULAR ORlfICE

        The left atrioventricular orifice usually narrows in a long-standing rheumatic endocarditis (stenosis ostii venosi sinistri). In very rare cases mitral stenosis may be congenital or secondary to septic endocarditis. The atrioventricular orifice narrows due to adhesion of the mitral cusps, their consolidation and thickening, and also shortening and thickening of the tendons. The valve thus becomes a diaphragm or a funnel with a slit in the middle. Cicatricial and inflammatory narrowing of the valvular ring is less important in genesis of mitral stenosis. The valve may be calcified in longstanding stenosis.

            Rheumatic fever is the leading cause of mitral stenosis (MS. Other less common etiologies of obstruction to left atrial outflow include congenital mitral valve stenosis, cor triatriatum, mitral annular calcification with extension onto the leaflets, systemic lupus erythematosus, rheumatoid arthritis, left atrial myxoma, and infective endocarditis with large vegetations. Pure or predominant MS occurs in approximately 40% of all patients with rheumatic heart disease and a history of rheumatic fever. In other patients with rheumatic heart disease, lesser degrees of MS may accompany mitral regurgitation (MR) and aortic valve disease. With reductions in the incidence of acute rheumatic fever, particularly in temperate climates and developed countries, the incidence of MS has declined considerably over the past few decades. However, it remains a major problem in developing nations, especially in tropical and semitropical climates.

            In rheumatic MS, the valve leaflets are diffusely thickened by fibrous tissue and/or calcific deposits. The mitral commissures fuse, the chordae tendineae fuse and shorten, the valvular cusps become rigid, and these changes, in turn, lead to narrowing at the apex of the funnel-shaped (“fish-mouth”) valve. Although the initial insult to the mitral valve is rheumatic, the later changes may be a nonspecific process resulting from trauma to the valve caused by altered flow patterns due to the initial deformity. Calcification of the stenotic mitral valve immobilizes the leaflets and narrows the orifice further. Thrombus formation and arterial embolization may arise from the calcific valve itself, but in patients with atrial fibrillation (AF), thrombi arise more frequently from the dilated left atrium (LA), particularly the left atrial appendage.

 

            If stenosis is significant and the orifice is narrowed from the normal 4-6 cm² to 1.5 cm² and less, haemodynamics becomes affected considerably. During diastole, blood fails to pass from the left atrium to the left ventricle and the remaining blood is added to the blood delivered from the pulmonary veins. The left atrium thus becomes overfilled with blood, the pressure in the atrium increases. Excess pressure is first compensated for by intensified contraction of the atrium and its hypertrophy, but the force of the left atrial muscle is insufficient to compensate permanently for the pronounced narrowing of the mitral orifice and its contractile force soon weakens; the atrium becomes dilated, and the pressure inside it rises. This in turn increases pressure in the pulmonary veins, produces a reflex spasm in the arterioles of the lesser circulation and increases pressure in the pulmonary artery. All this requires intensified work of the right ventricle, which later also becomes hypertrophied. The left ventricle in mitral stenosis receives smaller volumes of blood and is therefore less active; its size slightly decreases.

Pathophysiology

            Iormal adults, the area of the mitral valve orifice is 4–6 cm². In the presence of significant obstruction, i.e., when the orifice area is reduced to < ~2 cm², blood can flow from the LA to the left ventricle (LV) only if propelled by an abnormally elevated left atrioventricular pressure gradient, the hemodynamic hallmark of MS. When the mitral valve opening is reduced to <1 cm², often referred to as “severe” MS, a LA pressure of ~25 mmHg is required to maintain a normal cardiac output (CO). The elevated pulmonary venous and pulmonary arterial (PA) wedge pressures reduce pulmonary compliance, contributing to exertional dyspnea. The first bouts of dyspnea are usually precipitated by clinical events that increase the rate of blood flow across the mitral orifice, resulting in further elevation of the LA pressure (see below).

            To assess the severity of obstruction hemodynamically, both the transvalvular pressure gradient and the flow rate must be measured. The latter depends not only on the CO but on the heart rate as well. An increase in heart rate shortens diastole proportionately more than systole and diminishes the time available for flow across the mitral valve. Therefore, at any given level of CO, tachycardia including that associated with AF augments the transvalvular pressure gradient and elevates further the LA pressure. Similar considerations apply to the pathophysiology of tricuspid stenosis.

            The LV diastolic pressure and ejection fraction (EF) are normal in isolated MS. In MS and sinus rhythm, the elevated LA and PA wedge pressures exhibit a prominent atrial contraction (a wave) and a gradual pressure decline after mitral valve opening (y descent). In severe MS and whenever pulmonary vascular resistance is significantly increased, the pulmonary arterial pressure (PAP) is elevated at rest and rises further during exercise, often causing secondary elevations of right ventricular (RV) end-diastolic pressure and volume.

Cardiac Output

            In patients with moderate MS (mitral valve orifice 1.0 cm²–1.5 cm²), the CO is normal or almost so at rest but rises subnormally during exertion. In patients with severe MS (valve area <1.0 cm²), particularly those in whom pulmonary vascular resistance is markedly elevated, the CO is subnormal at rest and may fail to rise or may even decline during activity.

Pulmonary Hypertension

            The clinical and hemodynamic features of MS are influenced importantly by the level of the PAP. Pulmonary hypertension results from: (1) passive backward transmission of the elevated LA pressure; (2) pulmonary arteriolar constriction, which presumably is triggered by LA and pulmonary venous hypertension (reactive pulmonary hypertension); (3) interstitial edema in the walls of the small pulmonary vessels; and (4) organic obliterative changes in the pulmonary vascular bed. Severe pulmonary hypertension results in RV enlargement, secondary tricuspid regurgitation (TR) and pulmonic regurgitation (PR), as well as right-sided heart failure.

 

      Clinical picture. When congestive changes occur in the lesser circulation, the patient develops dyspnoea and palpitation on physical exertion; he complains of pain in the heart, cough, and haemoptysis. Inspection reveals  acrocyanosis and cyanotic blush on the face. If the disease develops in childhood, the patient’s physical growth often slows down and infantilism may develop (“mitral nanism”). Visual examination of the heart region often reveals a cardiac beat consequent upon dilatation and hypertrophy of  the right ventricle. The apex beat is not intensified; its palpation can reveal  diastolic cat’s purr (presystolic thrill). The broadening of cardiac dullness to the right and superiorly due to hypertrophy of the left atrium and right ventricle can be determined by percussion. The heart becomes “mitral” in configuration.

 

Mitral face

 

            In auscultation of the heart the first sound at the apex becomes loud and snapping because the left ventricle receives little blood and its contraction is fast. An adventitious sound due to the opening of the mitral valve  can be heard at the apex beat. It follows the second sound of the heart. The loud first sound, second sound, and the sound of mitral valve opening give a specific murmur which is characteristic of mitral stenosis. The second sound becomes accentuated over the pulmonary trunk when pressure in the lesser circulation increases. Diastolic murmur is characteristic of mitral stenosis because the passage from the left atrium to the ventricle during diastole is narrowed. This murmur can be heard to follow the mitral valve opening sound (protodiastolic murmur) because the velocity of the blood flow in early diastole is higher due to the pressure difference in the al and the ventricle. The murmur disappears when the pressures equalize. If stenosis is not pronounced, the murmur can be heard only at the diastole, immediately before systole proper (presystolic murmur); it arises during acceleration of the blood flow at the end of ventricular diastole because of the early atrial systole. Diastolic murmur can be heard in mitral stenosis during the entire diastole. It increases before systole and joints the first snapping sound.

       The pulse in mitral stenosis may be different on the left and right arms. In considerable hypertrophy of the left atrium, the left subclavian artery is compressed and the pulse on the left arm becomes smaller (pulsus differens). If the left ventricle is not filled completely and the stroke volumej decreased, the pulse becomes small (pulsus parvus). Mitral stenosis is often complicated by atrial fibrillation, and the pulse becomes arrhythmic. Arterial pressure usually remains normal; the systolic pressure sometimes slightly decreases and diastolic pressure increases.

 

 

       X-ray patterns of a heart show the specific enlargement of the left atrium, which leads to disappearance of the heart waist and “mitral” configuration appears. Enlargement of the left atrium is determined in the first oblique position by the degree of displacement of the oesophagus which becomes especially vivid with barium sulphate suspension. If pressure in the lesser circulation increases, X-rays show swelling of the pulmonary arch and hypertrophy of the right ventricle. X-ray pictures sometimes show calcification of the mitral valve. Pneumosclerosis develops during long-standing hypertension of the lesser circulation; it may also be revealed during X-ray examination.

 

X-ray in mitral stenosis. Mitral heart configuration.

 

        The ECG of the heart with mitral stenosis shows hypertrophy of the left atrium and the right ventricle: the amplitude and duration of the P⁵ wave increase, especially in the first and second standard leads; the electrical axis of the heart deviates to the right, a high R wave appears in the righr chest leads and a pronounced S wave in the left chest leads.

 

ECG in mitral stenosis

 

 

 

        A phonocardiogram taken at the apex shows the high amplitude of the first sound; the second sound is followed by the mitral valve opening sound and diastolic murmur; the amplitude of the second sound over the pulmonary artery increases compared with that over the aorta. If PCG and ECG are taken synchronously, attention should be paid to the  length of the interval Q-I sound (from the beginning of the Q wave on the  ECG to the first sound on the PCG) and the second sound—Q interval.

         Echocardiograms in mitral stenosis are characterized by the following:

     1. The A wave, describing the maximum opening of the atrial systole either decreases or disappears altogether

2.The speed of diastolic closure of the anterior mitral cusps decreases to decrease the E-F slope.

3.Movements of the cusps change. The cusps of a normal mitral valve move in the opposite direction to set apart during diastole: the anterior cusp moves toward the anterior wall while the posterior cusp to the posterior wall. In stenosis, these movements become unidirectional because the more massive anterior wall pulls the posterior one by adhesion. The movement of the valve is represented on the echocardiogram in the form of a square wave. Enlargement of the left atrium and changes in the cusps (fibrosis, calcinosis) can also be detected by echocardiography.

            Mitral stenosis soon becomes attended by congestion in the lesser circulation which requires greater work of the right ventricle. Decreased contractility of the right ventricle and venous congestion in the greater circulation develop therefore in mitral stenosis earlier and more often than in mitral incompetence.

            Dilatation of the right ventricle and weakening of its myocardium are sometimes attended by relative tricuspid insufficiency. Moreover, long-standimg venous congestion in the lesser circulation in mitral stenosis causes, with time, sclerosis of the valves and growth of connective tissue in the lungs. Another obstracle to the blood flow is thus created in the lesser circulation and this adds to the difficulties in the work of the right ventricle.

            Transthoracic two-dimensional echocardiography (TTE) with color flow Doppler imaging provides critical information, including an estimate of the transvalvular peak and mean gradients and of mitral orifice size, the presence and severity of accompanying MR, the extent of restriction of valve leaflets and their thickness, the degree of distortion of the subvalvular apparatus, and the anatomic suitability for percutaneous mitral balloon valvotomy (PMBV; see below). In addition, TTE provides an assessment of the size of the cardiac chambers, an estimation of LV function, an estimation of the pulmonary artery pressure (PAP), and an indication of the presence and severity of associated valvular lesions. Transesophageal echocardiography (TEE) provides superior images and should be employed when TTE is inadequate for guiding therapy. TEE is especially indicated to exclude the presence of left atrial thrombi prior to PMBV.

 

AORTIC INCOMPETENCE

            Aortic incompetence (aortic insufficiency) is the failure of the aortic valve to close completely during ventricular diastole; blood thus leaks back into the left ventricle. Aortic incompetence is usually secondary to rheumatic endocarditis, and less frequently bacterial (septic) endocarditis, syphilitic affection of the aorta, or atherosclerosis. Inflammatory and sclerotic changes occurring in the base of the cusps during rheumatic endocarditis make them shrink and shorten. Atherosclerosis and syphilis can affect only the aorta (to distend it), while the valve cusps are only shortened. The cicatricial changes may extend onto the cusps to disfigure them. Parts of the valve disintegrate in ulcerous endocarditis associated with sepsis and the cusps are affected with their subsequent cicatrization and shortening.

            Haemodynamics. During diastole, blood is delivered into the left ventricle not only from the left atrium but also from the aorta due to regurgitation, which overfills and distends the left ventricle during diastole. During systole the left ventricle has to contract with a greater force in order to expell the larger blood volume into the aorta. Intensified work of the left ventricle causes its hypertrophy, while the increased systolic volume in the aorta causes its dilatation

        Aortic incompetence is characterized by a marked variation in blood pressure in the aorta during systole and diastole. An inc         reased volume of blood in the aorta during systole increases systolic pressure and since part of blood is returned during diastole into the.ventricle, diastolic pressure quickly drops.

        Clinical picture. Subjective condition of patients with aortic in  competence may remain good for a long time because the defect is compensated for by harder work of the powerful left ventricle. Pain in the   heart (anginal in character) may sometimes be felt; it is due to relative coronary insufficiency because of pronounced hypertrophy of the myocardium and inadequate filling of the coronary arteries under low diastolic pressure in the aorta. The patient may sometimes complain of giddiness which is the result of deranged blood supply to the brain (which is also due diastolic pressure).

        If contractility of the left-ventricular myocardium is impaired, congestion in the lesser circulation develops and the patient complaints of dyspnoea, tachycardia, weakness, etc. The skin of the patient is pallid due to insufficient filling of the arterial system during diastole. Marked variations in the pressure in the arterial system during systole and diastole count for the appearance of some signs, such as pulsation of the perphieral arteries, the carotids (carotid shudder), subclavian, brachial, temporal and other arteries; rhythmical movements of the head synchronous with the pulse (Musset’s sign), rhythmical change in the colour of the nail bed under a slight pressure on the nail end, the so-called capillary pulse (Quincke’s pulse), rhythmical reddening of the skin after rubbing, etc.

 

Appearance of the patient with aortic incompetence

        The apex beat is almost always enlarged and shifted to the left and inferiorly. Sometimes, along with the elevation of the apex beat, a slight depression in the neighbouring intercostal spaces can be observed The apex beat is palpable in the sixth and sometimes seventh intercostal space laterally of the midclavicular line. The apex beat is diffuse, intense, rising like a dome. This indicates significant enlargement of the left ventracle. The border of cardiac dullness can be found (by percussion) to shift to the left; the heart becomes “aortic” (with pronounced waist of the herat.

            Auscultation reveals decreased first sound at the apex, since during left-ventricular systole the period when the valves are closed is absent. The second sound on the aorta is also weak, and if the valve is damaged significantly, it can be inaudible. The second sound can be quite loud in atherosclerotic affection of the aorta. Diastolic murmur heard oer the aorta and at the Botkin-Erb listening point is characteristic. This is  a low blowing protodiastolic murmur which weakens by the end of diastole sa the blood pressure in the aorta drops and the blood-flow rate decreases. The described changes in the sounds and murmurs are clearly visible on phonocardiogram. Murmurs of functional aetiology can also be heard in aortic incompetence at the heart apex. If the left ventricle is markedly dilated, relative mitral incompetence develops and systolic murmur can be heard at the apex. Diastolic murmur (presystolic or Austin-Flint murmur) can sometimes be heard. It arises due to an intence regurgitation of the blood that moves aside the mitral valve cusp to account for functional mitral stenosis. Doubled sound (Traube souble sound) nd doubled Vinogradov-Durozierz murmur can sometimes be heard over the femoral artery in this disease.

 

            The pulse is fast, full, and high, which is due to high pulse pressure and increased volume of blood deliverred into the aorta during systole. Arterial pressure constantly varies^ the systolic pressure rises and diastolic falls, and the pulse pressure is therefore high.

X-ray studies show an enlarged left ventricle with a distinct waist of the heart and dilatation of the aorta; pulsation of the aorta is intense.

            The ECG also reveals various signs of hypertrophy of the left ventricle: the electrical axis is deviated to the left, the S waves in the right chest leads are deep and the amplitude of the R wave is higher in the left chest leads; these signs often combine with signs of overstrain in the left ventricle and relative coronary insufficiency (changes in the terminal part of the ventricular complex, displacement of the S-T interval, and the negative T wave).

Echocardiograms taken from patients with aortic failure show flutter of the anterior mitral cusp during diastole caused by the thrust of the blood regurgitated from the aorta into the ventricle.

ECG in aortic incompetence

 

 

 

 

            Ultrasound in aortic incompetence: uncomplete closure of aortic valve, enlargement of the left ventricle

Ulrtasound examimation in aortic incompetence:

 

 

 

 

 

 

X-ray in aortic incompetence: aortic heart configuration

 

            Aortic incompetence can for a long time be compensated for by intensified work of the hypertrophied left ventricle. When its contractile force decreases, congestion in the lesser circulation develops. Acute weakness of the left ventricle sometimes develops and is manifested by an attack of cardiac asthma. Dilatation of the weakened left ventricle can cause relative mitral incompetence. This increases venous congestion in the lesser circulation associated with decompensated aortic incompetence and adds to the load on the right ventricle. This is mitralization of aortic incompetence, which may become the cause of venous congestion in the greater circulation.

 

AORTIC STENOSIS

            The narroving of the aortic orifice (aortic stenosis) interferes with expulsion of blood into the aorta during contraction of the left ventricle. Aortic stenosis is usually caused by rheumatic endocarditis; less frequently it develops due to bacterial endocarditis, atherosclerosis, or it may be congenital. Stenosis results from adhered aortic valve cusps or develops due to cicatricial narrowing of the aortic orifice.

        Haemodynamics. During systole, the left ventricle is not emptied completely because part of blood fails to pass the narrowed orifice into the aorta. A new normal portion of blood delivered during diastole from the left atrium is mixed with the residual volume and the ventricle becomes overfilled. The pressure inside it thus rises. This disorder is compensated for by an intensified activity of the left ventricle to cause its hyperthrophy.

        Clinical picture. Aortic stenosis can remain compensated for years and would not cause any unpleasant sublective sensations (even during intense physical exertion). If obstruction of the aortic orifice is considerable, infufficient blood ejection into the arterial system upsets normal blood supply to the hypertrophied myocardium and the patient feels pain in the heart (angina pectoris-type pain). Disordered blood supply to the brain is manifested by giddiness, headache, and tendency to fainting. These symptoms like pain in the heart would more likely occur during physical and emotional stress.

            The skin of the patient is pallid due to insufficient blood supply to the  arterial system. The apex beat is displaced to the left, less frequently ineriorly; it is diffuse, high, and resistant. Systolic thrill (cat’s purr) can be palpated in the region of the heart. Percussion reveals displacement of the left heart border; the heart is “aortic” due to hypertrophy of the left ventricle.  Auscultation of the heart at its apex reveals diminished first sound due to overfilling of the left ventricle and prolongation of systole. The second sound is diminished over the aorta. If the aortic cusps adhere and are immobile, the second sound can be inaudible. Rough systolic murmur over the aorta is characteristic. This murmur is generated by the blood flow through the narrowed orifice. It is conducted by the blood onto the carotids and can sometimes be heard in the interscapular space. The pulse is small, slow, and rare, since the blood slowly passes into the aorta and its volume is decreased. Systolic arterial pressure is usually diminished, while diastolic remains normal or increases. The pulse pressure is therefore decreased.

 

        X-ray examination shows hypertrophied left ventricle, “aortic” configuration of the heart, and dilatation of the ascending aorta (poststenotic); the cusps of the aortic valve are often calcified.

The ECG usually shows signs of hypertrophy of the left ventricle and sometimes of coronary insufficiency.

 

ECG in aortic stenosis

            The phonocardiogram shows the specific changes in the heart sounds: diminished amplitudes of the first sound at the heart apex and of the second sound over the aorta. Systolic  murmur over the aorta is typical; its oscillations are recorded in the form of -specific diamond-shaped  figures.

            Sphygmograms of the carotids reveal slowed ascent and descent of the pulse wave (slow pulse), small amplitude of the pulse waves, and specific serrated pattern of their peaks (sphygmograms in the form of a cock’s comb) showing oscillations associated with conduction of systolic murmur onto the neck vessels.

        Echocardiograms show decreased opening of the aortic valve during systole. Echoes from the cusps become more intense and signs of hypertrophy of the left ventricle appear.

            The key findings are LV hypertrophy and, in patients with valvular calcification (i.e., most adult patients with symptomatic AS), multiple, bright, thick, echoes from the valve.

            Still frame two-dimensional echocardiographic image from the parasternal long axis view of a patient with aortic stenosis. The aortic valve is calcified with restricted opening during systole. Ao, aorta; RV, right ventricle; LA, left atrium; LV, left ventricle.

 

 

 

X-ray in aortic stenosis. Aortic heart configuration

 

Ultrasound examination in aortic stenosis. Narrowing of aortic aperture, enlargement of the left ventricle

 

        Aortic stenosis remains compensated for a long time. Circulatory insuf­ficiency develops in diminished contractility of the left ventricle and it is manifested as in aortic incompetence.

Treatment. Conservative treatment means management of heart failure. Operative treatment – implantation of artificial prostesis in incompetence or comissuritomy in stenosis.

The natural history of untreated organic and functional mitral regurgitation emphasises the importance of treatment of patients with severe regurgitation. Because the effects of various treatments on survival have not been tested in randomised clinical trials, the value of any approach is estimated on the basis of outcome studies.

            Management strategy for patients with chronic severe mitral regurgitation.  Mitral valve (MV) repair may be performed in asymptomatic patients with normal left ventricular (LV) function if performed by an experienced surgical team and if the likelihood of successful MV repair is >90%. AF, atrial fibrillation; Echo, echocardiography; EF, ejection fraction; ESD, end-systolic dimension; eval, evaluation; HT, hypertension; MVR, mitral valve replacement. (From Bonow et al.)

            Medical treatment aims to prevent progression of organic disease. Prevention of endocarditis is directed at forestalling catastrophic infectious complications and sudden mitral regurgitation progression associated with endocarditis. Diuretics often reduce or eliminate symptoms of disease but such improvement should not unduly reassure physicians. Patients who had transiently severe symptoms and improved with treatment continue to be at high risk and should be promptly assessed for surgery.

             Treatment of organic mitral regurgitation with vasodilators has been advocated on the basis of experimental studies showing reductions in acute RVol and even ERO area with blood pressure reduction. Acutely ill patients with mitral regurgitation benefit from vasodilator treatment. However, despite some encouraging data, translation to chronic treatment of organic disease is unresolved because reported series were small, rarely randomised, and contradictory in conclusions. Activation of the tissue (not systemic) renin-angiotensin myocardial system was shown in organic mitral regurgitation. Consistent pilot studies suggest potential of drugs blocking tissue renin-angiotensin system to stabilise organic disease severity and consequences. The effect of such treatments on clinical outcome remains to be shown. β blockade in organic mitral regurgitation has only been tested in animal models and remains conjectural. Conversely, in functional disease, medical treatment has been better studied than in organic disease. Maximum medical treatment of patients with heart failure and left-ventricular dysfunction reduces functional mitral regurgitation. Specifically β blockade—with carvedilol or long-acting metoprolol—and inhibition of angiotensin-converting enzyme reduce functional mitral regurgitation severity. These therapies are recommended for treatment of left-ventricular dysfunction. Thus, non-urgent surgical indications should be reviewed after maximum medical treatment has taken effect.

            Interventional treatment is not yet approved for clinical use and remains investigational. Percutaneous revascularisation of patients with ischaemic regurgitation is possible but patients are often left with residual regurgitation that affects prognosis so that more effective treatment is necessary. Resynchronisation treatment in left-ventricular dysfunction with delayed conduction might improve functional mitral regurgitation. Two specific interventional approaches to treatment are discussed here.

            Valvular edge-to-edge attachment mimics the surgical procedure proposed by Alfieri and colleagues, creating a tissue bridge between anterior and posterior leaflets. Percutaneously, this technique uses a clip or sutures deployed through trans-septal catheterisation. Experimental studies have shown success and reliable clip or suture placement through the trans-septal approach. Early trials also suggest safety and feasibility with close echocardiographic guidance in centres with much experience of interventional valvular procedures. Data for how well this intervention works are preliminary but encouraging,128 suggesting that more than 80% of patients can be discharged from hospital with a clip, and mild or little mitral regurgitation. A randomised trial comparing percutaneous clip and surgery is in progress. The edge-to-edge technique has important limitations. First, the application of this technique is restricted to localised prolapse of the central segment of the anterior and posterior leaflets. Second, annular dilatation is not addressed by the procedure and might cause residual regurgitation.

            Annuloplasty aimed at reduction of annular dilatation is under investigation mostly with coronary sinus cinching. Technically, stabilisation of material with sufficient constraining force to obtain more than 20% diameter reduction is a challenge. Most devices are composed of anchoring devices placed in the distal and proximal coronary sinus and an intermediate tensioning or supporting element. Experimentally, reduction of mitral regurgitation is achievable, but clinical results are preliminary. Feasibility through a jugular approach and safety seem to be acceptable. Potential limitations are those of annuloplasty (incomplete valve tenting correction) and those of coronary sinus approach that might reduce only part of the annular circumference with an effectiveness limited by the 1—2 cm sinus-annular distance. Because of safety concerns related to proximity of the coronary sinus and circumflex artery with potential artery compression, non-coronary sinus approaches to annuloplasty and percutaneous ventricular remodelling-constraint devices are being investigated.

            On the basis of the success of balloon valvuloplasty for mitral stenosis, percutaneous treatment of mitral regurgitation is expected to be successful but this success will necessitate complex development that needs strong cardiologist—engineer collaboration and rigorous assessment.

            Surgical treatment of mitral regurgitation is the only approach with defined clinical success, providing sustained relief of symptoms or heart failure. However, no randomised trial has been done to prove mortality or cardiac event reduction. The standard surgical approach is a median sternotomy, but sometimes only partial sternotomy or minimally invasive surgery through thoracoscopic approach can be used.

            Valve repair includes an array of valvular, subvalvular, and annular procedures aimed at restoration of leaflet coaptation (ie, valvular normal function) and elimination of mitral regurgitation. These surgical techniques are more successful with redundant than with retracted or calcified leaflets. For valve prolapse, typical repair is resection (triangular or quadrangular) of the prolapsed posterior leaflet segment whereas the anterior leaflet is rarely resected. Subvalvular support can be obtained by chordal transfer or artificial chords rather than chordal shortening. Annuloplasty is routinely used with annular bands or flexible or rigid rings. Many additional technical procedures might be used at the surgeon’s discretion to restore coaptation and valve competence. Conversely, in functional mitral regurgitation, valve repair is rather uniform with restrictive annuloplasty substantially reducing the anteroposterior annular diameter. New rings aimed at annular reshaping, specific to each cause of functional regurgitation (ischaemic disease or cardiomyopathy) are now available but their incremental value (compared with traditional rings) is not defined. Valve repair is done in about half of patients who undergo surgery for mitral regurgitation in the USA and Europe. In centres with surgeons proficient in valve repair, more than 80—90% repair rates are achieved. A failed repair is caused rarely by systolic anterior motion of the mitral valve due to excessively redundant tissue or by stenosis, but more often by insufficient correction of a prolapse, recurrence of ruptured chords, and excessive tissue retraction or resection. Overall, reoperation after 10 years is necessary in 5% of patients with repaired posterior leaflet prolapse and 10% of those with anterior leaflet interventions. 20—30% of patients with repaired functional mitral regurgitation are estimated to have recurrent regurgitation. Reoperation rate is not greater after valve repair than after replacement and because of the morbidity and mortality advantages, valve repair is the preferred method of surgical correction of mitral regurgitation.

            Valve replacement involves insertion of a biological or mechanical prosthesis. Bioprosthetic valve replacement is associated with low embolic risk but shorter durability, whereas mechanical valve replacement is associated with high risk of embolism and haemorrhagic complications (due to intensive warfarin treatment) but has potential for long-lasting durability. Results of randomised trials showed that within 10 years of surgery these risks are balanced. Older age determines the probability that bioprosthetic durability will be longer than life expectancy, and is the main bioprosthesis insertion indication (usually >65 years of age). Ability to achieve high-quality anticoagulation and patient’s desire also affect the choice of prosthesis. Irrespective of the prosthesis selected, conservation of subvalvular apparatus is essential for preservation of ventricular function. The risk of prosthetic complications makes surgical indications more restrictive when valve replacement is likely.

Mitral Valvotomy

            Unless there is a contraindication, mitral valvotomy is indicated in symptomatic [New York Heart Association (NYHA) Functional Class II–IV] patients with isolated MS whose effective orifice (valve area) is < ~1.0 cm²/m² body surface area, or <1.5 cm² iormal-sized adults. Mitral valvotomy can be carried out by two techniques: PMBV and surgical valvotomy. In PMBV a catheter is directed into the LA after transseptal puncture, and a single balloon is directed across the valve and inflated in the valvular orifice. Ideal patients have relatively pliable leaflets with little or no commissural calcium. In addition, the subvalvular structures should not be significantly scarred or thickened and there should be no left atrial thombus. The short- and long-term results of this procedure in appropriate patients are similar to those of surgical valvotomy, but with less morbidity and a lower periprocedural mortality rate. Event-free survival in younger (<45 years) patients with pliable valves is excellent, with rates as high as 80–90% over 3–7 years. Therefore, PMBV has become the procedure of choice for such patients when it can be performed by a skilled operator in a high-volume center.

 

            Outcomes after surgery for functional disease remain suboptimum. Operative mortality is still high despite definite surgical improvements. Long-term mortality and heart failure rates are high, although not unexpected in patients with coronary disease, previous myocardial infarction, reduced ventricular function, and vascular comorbidity. These suboptimum outcomes explain uncertainties in surgical indications. The value of mitral repair compared with replacement is also debated because mitral regurgitation often recurs after repair as a consequence of continued ventricular remodelling, which results in recurrent valve tenting. Determinants of postoperative outcome are myocardial viability, preserved mitral competence, and absence of sustained or advanced ventricular remodelling. Postoperative outcome of functional mitral regurgitation due to cardiomyopathy is mediocre and whether it is improved compared with outcome under medical management is doubtful. However, with low operative mortality, postoperative heart failure and symptomatic improvements are possible.

 

RHEUMATIC FEVER as a main cause on AVHD

            Rheumatic fever is an inflammatory condition. It involves the connective tissue in the body. The most severe complication is rheumatic heart disease. This condition may permanently damage the heart valves. Symptoms of valve damage often don’t appear for 10-30 years after the initial event. In many developing countries, which account for almost two-thirds of the world’s population, streptococcal infections, rheumatic fever, and rheumatic heart disease remain a very significant public health problem.

Rheumatic fever is common among the children of the poor, where there is overcrowding and delay in the treatment of throat infections. Rheumatic fever is extremely rare under 2 years of age. Most cases of rheumatic fever occur in children aged 5-15 years.

Studies have shown that approximately 3% of individuals with untreated group A streptococcal pharyngitis will develop rheumatic fever. The epidemiology of rheumatic fever is also influenced by the serotypes of group A streptococci present in a population. The concept of “rheumatogenecity” of specific strains is largely based upon epidemiologic evidence associating certain serotypes with rheumatic fever (e.g., serotypes 1, 3, 5, 6, 18, etc.). Mucoid isolates are frequently associated with virulence and with rheumatic fever.

PATHOGENESIS More than half a century ago the pioneering studies of Lancefield differentiated beta-hemolytic streptococci into serologic groups. This ultimately led to the association of infection by the group A organism of the pharynx and tonsils (not of the skin) and the subsequent development of acute rheumatic fever. However, the mechanism(s) responsible for the development of rheumatic fever after an infection remains incompletely defined. Historically, approaches to understanding the pathogenesis of rheumatic fever have been grouped into three major categories:

1. direct infection by the group A streptococcus;

2. toxic effect of streptococcal extracellular products on the host tissues;

3. an abnormal or dysfunctional immune response to one or more as yet unidentified somatic or extracellular antigens produced by all (or perhaps only by some) group A streptococci.

There is insufficient evidence to support direct infection of the heart as the inciting event. Additionally, while toxins such as streptolysin O and others have been postulated to have a pathogenetic role, there is relatively little convincing evidence of this at the present time. Major efforts have focused on an abnormal immune response by the human host to one or more group A streptococcal antigens.

Classification of rheumatic fever.

Phase:

A. Acute: I degree – minimum, II degree – moderate, III degree – maximum

B. nonacute

Clinical-Anatomical characteristic of involvement of the heart:

1. Acute phase:

a. primary rheumocarditis without valvular involvement.

b. recurrent rheumocarditis with cardiac defect

c. rheumatic fever without obvious cardiac  involvement.

2. nonacute phase:

a. rheumatic myocardiosclerosis

b. cardiac defect

 

Clinical-Anatomical characteristic of involvement of visceral organs and systems:

1. Acute phase: carditis, polyathritis, serositis (pleuritis, peritonitis,abdominal syndrome), chorea, encephalitis, meningoencephalitis, cerebral vasculitis, vasculitis, nephritis, hepatitis, pneumonia, skin alteration, iritis, iridocyclitis, thyroiditis.

2. nonacute phase: results of the outcardiac involvement.

Course: Acute, subacute, recurrent, latent

 

 

Criteria for the grades of activity of rheumatic fever

 

In most published series, between 40 and 60% of patients with acute rheumatic fever have evidence of carditis, which is characterized by one or more of the following: sinus tachycardia, the murmur of mitral regurgitation  an S3 gallop, a pericardial friction rub, and cardiomegaly. The introduction of echocardiography has assisted in the identification of subtle abnormalities of the mitral valve, and these may be present in an additional 20% of patients who do not have an audible heart murmur. A prolonged PR interval and evidence of heart failure may be present as well, but these are nonspecific and may be found in a number of other diseases.

Healing of the rheumatic valvulitis may cause fibrous thickening and adhesion, resulting in the most serious complication of rheumatic fever, i.e., valvular stenosis and/or regurgitation. The mitral valve is involved most frequently, followed by the aortic valve.

However, isolated aortic valve disease as a consequence of acute rheumatic fever is quite rare. In patients with aortic valve disease due to rheumatic fever, the mitral valve is almost always simultaneously affected. Even minor degrees of rheumatic valvular involvement can lead to susceptibilities to infective endocarditis. Although rheumatic pericarditis can cause a serous effusion, fibrin deposits, and even pericardial calcification, it does not lead to constrictive pericarditis.

Carditis is the most serious manifestation of rheumatic fever, involves all the layers of the heart wall simultaneously. It occurs in as many as 40% of patients and may include cardiomegaly, new murmur, congestive heart failure, and pericarditis, with or without a rub and valvular disease. The inflammation of the pericardium (outer coating of the heart) is called pericarditis. The inflammation of the myocardium (heart muscle) is called myocarditis. The inflammation of the endocardium (internal lining of the heart wall) is called endocarditis. The involvement of the heart is revealed by the occurrence of new mitral and aortic murmurs and cardiomegaly. Very severe rheumatic heart disease may lead to heart failure. The heart lesions may remain and worsen with every recurrence of the acute rheumatic fever.

A migratory polyarthritis is present in as many as 75% of cases, most often affecting the ankles, wrists, knees, and elbows over a period of days. It usually does not affect the small joints of the hands or feet and seldom involves the hip joints. Since salicylates and other anti-inflammatory drugs usually cause prompt resolution of joint symptoms, it is important that the cliniciaot prescribe these medications until it is determined whether the arthritis is migratory. The arthritis of acute rheumatic fever is extremely painful. Pain can be controlled with codeine or similar analgesics until the diagnosis is established.  The arthritis lasts 1-5 weeks and subsides without residual deformity. The difference between arthralgia (subjective joint pain) and arthritis (joint pain and swelling) must be understood. Too often, arthralgia is used (incorrectly) as a major criterion.

Laboratory studies

            Acute phase reactants are useful in helping to recognize acute RF and also to exclude other diseases. C-reactive protein and erythrocyte sedimentation rates are helpful in monitoring inflammatory activity.

            Laboratory evidence of a preceding GAS infection should be sought, either by demonstration of GAS in the throat by culture or rapid streptoccocal antigen test, or using streptococcal antibody tests. Elevated or rising titers of antistreptolysin O (ASO) occur in more than 80% of patients with acute GAS pharyngitis. There is a remarkable response during the acute phase of RF. The test specificity has been shown to be 93% with ASO titers above 960 IU/ml.

            Prolonged P-R interval relative to heart rate is a nonspecific finding, present in more than one third of the patients. Low-voltage QRS complexes and ST segment changes may be found in the presence of pericarditis and pericardial effusion.

            Endomyocardial biopsy is invasive and does not appear to provide additional diagnostic information where there is a clinical consensus about the diagnosis of RF, with a diagnostic sensitivity in one relatively large study of 27%. It should be limited to clinical investigation.