Definition.—Tricuspid incompetency is an imperfect closure of the tricuspid valves, due to dilatation of the right ventricle or to disease of the valves.
Etiology.—While tricuspid insufficiency may be the result of organic valvular lesion, it occurs far more frequently as the result of dilatation and is relative. Actual disease of the valves may result from fetal endocarditis. Notwithstanding the rarity of sclerosis in the valve segments, Bramwell's statistics show that fifty per cent of all cases of endocarditis are attended by tricuspid insufficiency.
It is far more common in children, and decreases with advancing years. It is generally due to mitral disease. Obstruction to the pulmonary circulation, due to chronic bronchitis, when associated with emphysema and tuberculosis of the lung or fibroid pneumonia, is a frequent cause.
Pathology.—As a result of the failure of the tricuspid valves to close the auriculo-ventricular opening, there is regurgitation into the auricle, which, meeting the great mass of blood from the venae cavae, causes congestion and enlargement of the entire venous system. Having no assistance from a fellow-member, as the left heart has, in its many efforts to overcome increased work, there can be but little compensatory changes..
The right ventricle undergoes slight hypertrophy, and for a time the pulmonary circulation is fairly maintained; but the quantity of blood from the right auricle, being abnormally large, the right ventricle becomes enormously dilated, which causes thinning of its walls. As this progresses, its power becomes feeble, and, not being able to force the blood through the pulmonary artery, the right auricle, the venae cavae, and even the peripheral veins, become greatly dilated, cyanosis is marked, and the case ends fatally.
Symptoms.—The early symptoms are generally obscured by the primary lesion. If this lesion be the result of mitral insufficiency, the symptoms accompanying it will be present long before those relating to changes of the right heart, or, if due to wrongs of the respiratory apparatus, the symptoms due to chronic bronchitis or pulmonary lesion will mask those relating directly to the tricuspid incompetency.
When fully developed, however, they become characteristic, and are suggestive of passive congestion of the lungs and marked engorgement of the systemic veins. Dyspnea at first, after slight exertion, soon becomes more or less constant. There is frequent cough and sometimes hemorrhage from the lungs. The pulse is small and irregular. Dizziness, with dull headache, may be attributed to passive hyperemia of the brain.
There is disturbance of the gastro-intestinal functions owing to engorgement of their structures, while the liver is found to be enlarged and indurated. The spleen shares in the general congestion, and a sense of weight and fullness is experienced in the left hypochondrium. The urine is scanty, high-colored, and contains albumen.
Physical Signs.—Inspection.—If the tricuspid insufficiency has been preceded by mitral regurgitation, the apex beat will be seen in the normal position or slightly to the right, owing to the increased hypertrophy of the right ventricle. Epigastric pulsation, with bulging of the lower sternal region, is not uncommon.
The most characteristic and pathognomonic sign is the visible pulsations of the veins of the neck with each cardiac systole; the lower portion of the jugulars first, and later in the disease throughout their entire course. It may also be seen in the subclavian, axillary, thyroid, and mammary veins in advanced cases. To bring this out more distinctly, the patient should be requested to hold the breath a few seconds before taking a full respiration.
Palpation.—If, when the patient lies on the back with the arms raised, we place the left hand over the right mid-axillary region, and the right hand over the upper abdominal region, we get an expansile pulsation of the liver synchronous with that of the right ventricle. A systolic thrill may sometimes be felt over the right ventricle.
The pulse depends to a great extent upon valvular lesions of the left heart which have preceded the tricuspid changes, though in most cases it is frequent, feeble, and irregular. Popofif has called attention to the greater weakness of the pulse of the right wrist, due to pressure on the innominate artery by the enlarged right auricle and venae cavae.
Percussion.—Percussion reveals dullness extending an inch or more to the right of the sternum and downwards toward the epigastrium. It may also extend to the second interspace.
Auscultation.—A systolic murmur, soft and low in character, is usually heard at the lower part of the sternum near the ensiform cartilage, though not always, if the heart be weak. There is accentuation of the pulmonic second sound in the early stage, but as the incompetency increases, it loses its sharpness, and may finally disappear.
To the skilled ear, auscultation of the lower part of the jugular vein may reveal a venous sound, due to the closure of the valve at this point. This is before the valve becomes insufficient.
Diagnosis.—The venous pulse is the most significant of all physical signs, either as seen in the neck or observed by palpating the liver. If with this, we detect a systolic murmur, whose maximum intensity is heard over the lower sternum, and percussion reveals dullness to the right of the sternum, the diagnosis is complete.