Rheumatic heart disease – Cardiology Basics

Rheumatic heart disease – Cardiology Basics

Rheumatic heart disease is a group diseases which occur secondary to heart valve damage from rheumatic fever. Rheumatic fever is a disease in which antibodies produced by the body against streptococci cross react with different tissues in the body, especially the heart.

Group A beta hemolytic streptococci causing sore throat are involved in the pathogenesis of rheumatic fever. Most of the long term damage following rheumatic fever is caused by damage to heart valves . Initial manifestation of rheumatic fever is with polyarthritis, usually of the large joints.

But it does not usually cause long lasting damage to the joints, though in the initial stage the joints are quite painful. Heart valve damage may be initially silent and manifest later with severe rheumatic heart disease.

Other likely manifestations of rheumatic fever are involuntary movements known chorea, subcutaneous nodules over the bony prominences and scalp, and erythema marginatum. Fortunately, polyarthritis and chorea do not occur at the same time. Otherwise, it would have caused severe pain in the inflamed joints.

Chorea is usually a delayed manifestation of rheumatic fever while joint pain is an early manifestation. By that time, polyarthritis would have subsided. Subcutaneous nodules and erythema marginatum do not cause much problem to the child with rheumatic fever as they disappear soon. Polyarthritis also subsides sooner or later, even without treatment. But heart valve damage progresses most often, either slowly or rapidly.

In the initial stage of rheumatic fever, the heart valves are inflamed and may become regurgitant. Most commonly affected valves are the mitral valve and the aortic valve. It is thought that valves with highest hemodynamic load in the closed position are involved more in rheumatic fever. Mitral valve faces the systolic left ventricular pressure in closed position and aortic valve faces the diastolic aortic pressure in the closed position.

Inflammation of the heart valves in rheumatic fever is known as rheumatic carditis. Occasionally inflammation of the myocardium and pericardium can also occur in rheumatic fever. These are called rheumatic myocarditis and rheumatic pericarditis respectively. Pericarditis can cause chest pain in children with rheumatic fever. Myocarditis can cause heart failure, though the more likely reason for heart failure in rheumatic fever is severe valvular regurgitations.

When there is severe damage to the heart valves in the initial stage, producing severe regurgitation, some of them may develop heart failure with breathlessness. Left ventricular failure with pulmonary edema is the cause for breathlessness.

Long term damage can occur in any of the four heart valves, though it is most common in mitral and aortic valves. The regurgitant lesions in mitral and aortic valves may recover partly after the initial attack of rheumatic fever. Sometimes the regurgitations progress and produce heart failure.

Very often it is a recurrent attack of rheumatic fever, which is not uncommon in developing countries, that causes more damage to the heart valves. That is why prevention of recurrence of rheumatic fever with regular long term penicillin prophylaxis is so important. If there is no recurrence of rheumatic fever valve damage in the initial phase may recover and even become normal later.

Chronic rheumatic heart disease occurs when the valve damage does not recover and progresses. The valves which are severely damaged and regurgitant initially, may become stenosed later due to progressive fibrosis. Mitral stenosis can cause progressive breathlessness with occasional episodes of pulmonary edema and hemoptysis sometimes. Pulmonary edema is because of increase in left atrial pressure which is transmitted back to the pulmonary veins and capillaries.

Aortic stenosis can cause exertional angina and syncope. Angina is because of increased oxygen demand from the hypertrophied left ventricle in aortic stenosis. Left ventricle gets hypertrophied in an attempt to overcome the outflow obstruction. Exertional syncope is because of peripheral vasodilatation in the setting of relatively fixed cardiac output producing cerebral hypoperfusion.

Tricuspid valve can be involved in rheumatic heart disease in two ways. Direct damage to the valve can cause regurgitation or stenosis. This is organic tricuspid valve disease. Another more common way of involvement of tricuspid valve is by tricuspid regurgitation caused by pulmonary hypertension.

When there is severe mitral stenosis, back pressure into lungs causes pulmonary hypertension which can become severe. Pulmonary hypertension in turn causes right ventricular hypertrophy and dilatation. When the pressure in the right ventricle rises too much, tricuspid valve is unable to hold on and becomes regurgitant. Dilatation of tricuspid annulus due to right ventricular dilatation also contributes. This is functional tricuspid regurgitation due to pulmonary hypertension.

Disease of the tricuspid valve increases pressure in the right atrium and in the veins draining blood to the right atrium. When pressure in the veins rise, it manifests as elevated jugular venous pressure and prominent neck veins. A prominent v wave is seen in the jugular venous pulse with severe tricuspid regurgitation, called as venous Corrigan.

Increase in back pressure in the inferior vena cava causes congestive hepatomegaly, which can be tender. Peripheral edema in the form of ankle edema occurs in heart failure. Ascites may occur in advanced tricuspid valve disease.

Pulmonary valve is the least commonly involved valve in the rheumatic process. But it can become regurgitant like the tricuspid valve, even without damage due to rheumatic fever. As in case of tricuspid valve, when there is severe pulmonary hypertension secondary to mitral stenosis, pulmonary valve is unable to hold on and becomes regurgitant. Very rarely, pulmonary valve can also be stenosed in rheumatic heart disease.

Severely narrowed heart valves can be opened either by balloon dilatation or by surgery. Sometimes they may have to be repaired or replaced with an artificial valve by open surgery. Balloon dilatation is the procedure of enlarging narrowed valves using balloon catheters. This fluoroscopy image shows dilatation of balloon catheter across a stenosed mitral valve. The catheter was introduced through the femoral vein under fluoroscopic guidance.

The procedure is done in a special procedure room known as cardiac catheterization laboratory or cathlab, under aseptic precautions. The device is then removed from the body after balloon dilatation of the stenosed valve. Long term penicillin prophylaxis to prevent recurrence of rheumatic fever has to be continued even after balloon valvotomy.

Balloon dilatation is routinely done for rheumatic mitral stenosis with good results and occasionally for tricuspid stenosis. The procedure may be better avoided if there is associated significant regurgitation in addition to stenosis.

Heart valves which have severe regurgitation are usually repaired by open surgery or more often replaced. This is because heart valves damaged by rheumatic fever are seldom suitable for repair. If a mechanical heart valve is placed, regular long term anticoagulation is needed to prevent thromboembolic complications and obstruction of the valve by thrombosis.

Regular monitoring of coagulation function is needed in that case to prevent bleeding and check effectiveness. Though new procedures for repairing heart valves using devices introduced through blood vessels without surgery like transcatheter aortic valve implantation or TAVI have come up recently, they are not ready for use in rheumatic heart disease.

This is for the same reason mentioned in case of surgical repair, the damage and distortion in valve structure often make these procedures unsuitable for rheumatic heart disease. Moreover, being new technologies, they are very costly, beyond the reach of patients with rheumatic heart disease located mostly in underprivileged regions of the world.