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Tricuspid insufficiency (TI), a valvular heart disease also called tricuspid regurgitation (TR), refers to the failure of the heart's tricuspid valve to close properly during systole. As a result, with each heart beat some blood passes from the right ventricle to the right atrium, the opposite of the normal direction.
Although congenital causes of tricuspid insufficiency exist, most cases are due to dilation of the right ventricle. Such dilation leads to derangement of the normal anatomy and mechanics of the tricuspid valve and the muscles governing its proper function. The result is incompetence of the tricuspid valve. Common causes of right ventricular dilation include left heart failure, pulmonary hypertension, and right ventricular infarction. One notable exception to right ventricular dilation as a cause of tricuspid insufficiency occurs in right-sided endocarditis (i.e. infection affecting the right side of the heart). In that case, there is direct damage to the tricuspid valve as a result of infection.
Other diseases can directly affect the tricuspid valve. The most common of these is rheumatic fever, which is a complication of untreated strep throat infections.
Tricuspid regurgitation occurs in roughly less than 1% of people and is usually asymptomatic. It may be found in those with a type of congenital heart disease called Ebstein's anomaly.
Other infrequent causes of tricuspid regurgitation include:
Another important risk factor for tricuspid regurgitation is use of the diet medications called "Fen-Phen" (phentermine and fenfluramine) or dexfenfluramine
Tricuspid insufficiency may be asymptomatic, especially if right ventricular function is well preserved. Conversely, edema, vague upper abdominal discomfort (from a congested liver), and fatigue (due to diminished cardiac output) can all be present to some degree. On examination, the jugular venous pressure is usually elevated, and 'CV' waves can be seen. The liver may be enlarged and is often pulsatile (the latter finding being virtually diagnostic of tricuspid insufficiency). Peripheral edema is often found. In severe cases, there may be ascites and even cirrhosis (so-called 'cardiac cirrhosis).
Triscuspid insufficiency may lead to the presence of a pansystolic heart murmur. Such a murmur is usually of low frequency and best heard low on the left sternal border. It tends to increase with inspiration. However, the murmur may be inaudible reflecting the relatively low pressures in the right side of the heart. A third heart sound may also be present.
Diagnosis is usually made by echocardiography although the find of a pulsatile liver and/or the presence of prominent CV waves in the jugular pulse is also essentially diagnostic.
In most cases, surgery is not indicated since the root problem lies with a dilated or damaged right ventricle. Medical therapy with diuretics is the mainstay of treatment. Unfortunately, this can lead to volume depletion and decreased cardiac output. Indeed, one must often accept a certain degree of symptomatic tricuspid insufficiency in order to prevent a decrease in cardiac output. Treatment with medicines to reduce cardiac afterload may also be of benefit but a similar risk of depressed cardiac output applies.