Shone’s complex is a series of birth defects of the left side of the heart. There is ring above the mitral valve, causing obstruction , parachute like mitral valve with obstruction, narrowing below the aortic valve and coarctation of aorta (narrowing of a region of the aorta). It was described by Shone and colleagues in 1963.
Category Archives: Heart Valve Disease
What is a heart murmur and what causes it?
Normally heart produces two heart sounds, name first and second heart sounds. An audible vibration in between the heart sounds is called a heart murmur. They are generally of longer duration than heart sounds. Many murmurs are innocent murmurs due to enhanced flow across the valves producing turbulence. Normal laminar flow of blood across the valves do not produce any murmur. Some of the murmurs are due to abnormal blood flow as in the case of leaky valve, obstructed valve or abnormal communication between the chambers of the heart in the form of birth defects in its walls.
Can someone with a heart murmur join the airforce?
It may vary from country to country, though generally they would prefer to have someone in perfect shape. You will have to check up with the forces in your country. The reason is that any failure of your system is not acceptable in a setting like the airforce. It may also depend on the available human resources in your country. It might be worth noting that most heart murmurs are innocent and not associated with significant heart disease and is suitable for a normal civilian life. But the stresses to the cardiovascular system in army are quite different from that in civilian life. Any significant heart problem is certainly to be excluded by appropriate investigations like an echocardiogram even in civilian life.
What are vegetations in infective endocarditis?
For bacterial endocarditis, it is a combination of thrombus with bacteria and leucocytes. Instead of bacteria there will be fungi in fungal endocarditis. These “clots” attached to valves are known as vegetations and can be detected by echocardiography. The vegetations can embolise and lodge in other locations where they can cause mycotic aneurysms and abscesses.
Mitral stenosis – narrowing of the valve between the left atrium and left ventricle
Mitral valve is the valve between the left atrium (upper chamber of the heart) and the left ventricle (lower muscular chamber of the heart). It is named so because of the resemblance to the headware of a bishop (mitre). Stenosid means narrowing of the orifice of the valve. Hence mitral stenosis is the narrowing of the orifice of the mitral valve producing an obstruction to the free filling of the left ventricle as it relaxes after a contraction. The commonest cause of mitral stenosis is rheumatic fever. Congenital mitral stenosis (mitral stenosis present from birth as a congenital anomaly) occurs in a very small group and other casues are extremely rare. Hence if mitral stenosis is documented, especially in the developing countries, it is most often of rheumatic etiology (cause). Mitral stenosis is considered severe if the valve area is less than 1 sq cm in an adult. An area more than 1.5 sq cm is consiered mild and between 1.5 and 1sq cm as moderate. Normal mitral valve has an area of around 5 sq cm and mitral stenosis is said exist when the valve area is less than 2 sq cm.
As the mitral valve becomes narrow, the pressure in the left atrium and consequently that in the pulmonary veins (blood vessels draining oxygenated blood from the lungs to the left atrium) and capillaries (small blood vessels connecting arteries and veins) rise. When the pulmonary capillary pressure reaches above 25 mm Hg, there is a chance for transudation (movement of fluid across the wall of the vessel) of fluid into pulmonary alveoli (small air chambers of the lung). This is known as pulmonary edema (collection of fluid in the small air chambers of the lung) and causes severe breathlessness. To begin with this occurs only during exercise while later on when the severity of mitral stenosis increases, this can occur at rest as well. Usually this occurs when the mitral valve area has gone below 1 sq cm. Hence a valve area less than 1 sq cm constitutes critical mitral stenosis. When the pulmonary capillary pressure is chronically (over a long period) elevated, it leads to reactive pulmonary arterial hypertension (increase in pressure in the pulmonary arteries, the vessels which carry blood from right ventricle to the lungs) and right ventricular failure as a consequence.
The modern treatment of mitral stenosis is balloon mitral valvotomy (opening up of the narrowed valve) if the valve is pliable and non-calcified. If the valve is calcified (hardened with increased calcium content), attempts of balloon valvotomy may sometimes result in severe mitral regurgitation (leakage of the valve) due to leaflet tear. This mandates urgent valve replacement. Hence elective mitral valve replacement is often resorted to in calcific mitral stenosis.
Abnormal rhythm of the heart known as atrial fibrillation can occur in long standing mitral stenosis as the left atrium becomes grossly dilated (enlarged). In atrial fibrillation, which is a rapid, irregular fine contraction of the atria due to very fast atrial electrical activity, there is no effective atrial pump function and a virtual atrial stand still. This leads to stagnation of blood in the left atrium and a tendency to clot formation. Clots can get dislodged from the atrial wall and carried by the blood circulation into other parts of the body. This process is known as embolism and can lead on to severe conditions like stroke,if it occludes a blood vessel of the brain. Mitral stenosis patients with atrial fibrillation need medications to prevent clot formation known as anticoagulants. Clotting function of the blood has to be monitored regularly while taking these medications in order to prevent excessive dosage and bleeding manifestations.