Why the Heart Muscle Thickens
Problems with the aorta—the main and largest artery in the body, which conducts blood away from the heart to the organs and tissues—can lead to a thickened heart muscle around it.
One of these problems is a narrowing of the valve of the aorta, a condition called aortic valve stenosis (constriction) or simply aortic stenosis. The aortic valve sits at the gate of the left ventricle, one of the two lower chambers of the heart. The valve regulates the flow of blood from the left ventricle to the aorta and prevents blood from backing up into the heart.
When the valve of the aorta does not completely open, it impedes the outflow of blood. The left ventricle must pump harder to squeeze the blood past the impaired aortic valve. In time, the strain causes the wall of the left ventricle to thicken (left ventricle hypertrophy). The heart may become weak and eventually suffer heart failure.
Causes of a Heart Thickened by a Narrowed Aorta
In most patients, aortic stenosis is due to a congenital abnormality of the aortic valve. In the elderly, age 70 and above, the valve may narrow because of scarring and calcification (the formation of calcium deposits) around it.
Other possible causes of aortic narrowing are a bout with rheumatic fever, radiation treatment to the chest and certain medications.
Symptoms of Aortic Stenosis
Symptoms of a thickened heart muscle around the aorta include chest pain (angina) and shortness of breath when the patient exerts effort due to an insufficient blood supply. These symptoms go away after minutes of rest. People with a severe aortic stenosis may become lightheaded or faint during exertion because the brain becomes starved for blood and blood pressure plummets.
Babies and children with aortic stenosis may look sweaty, fatigued, pale and small for their age, and their breathing may be quick.
How a Defective Aortic Valve Is Diagnosed
A thickened heart muscle due to a defective aortic valve is usually detected through physical examination. The doctor hears a heart murmur or other strange sounds through his stethoscope or feels the patient’s heart vibrating in his hand.
The diagnosis is confirmed with laboratory tests such as a chest x-ray, echocardiography, exercise stress test and cardiac catheterization, an invasive imaging process in which a tube is inserted into a blood vessel and brought to the heart to check for heart disease.
Treating a Thickened Heart and Constricted Aorta
People without symptoms or have mild symptoms of aortic stenosis with a left ventricle that is not thickened and functions normally may only need regular checkups with a cardiologist to check for progression of the disease. Patients with moderate aortic stenosis that has led to a thickened left ventricle may be asked to refrain from strenuous exercise. For patients with severe symptoms such as heart failure or abnormal heart rhythms, medications may be given, including diuretics to remove lung fluid and reduce high lung pressure. High blood pressure and high cholesterol should be treated also to help prevent or delay the development of aortic stenosis.
Antibiotics may be prescribed for patients who have acquired a narrowed aorta and thickened heart muscle following rheumatic fever or whose aortic valve has become infected by bacteria.
Valve replacement surgery is the recommended treatment for persons—young and old alike—who manifest symptoms or are asymptomatic but who have troubling outcomes on their diagnostic tests.
Sometimes a less invasive surgical procedure called balloon valvuloplasty is performed on infants and children. This is a procedure in which a balloon is placed across the valve of the aorta, inflated to widen the opening, then removed. It is not often done on adults, except on those too weak to undergo valve replacement surgery, because the opening inevitably shrinks again.
Health Communities.com at www.cardiologychannel.com/aorticstenosis/treatment.shtml
The Merck Manuals at www.merckmanuals.com/home/sec03/ch028/ch028f.html
PubMed Health at https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001230/