Aortic valve stenosis
Most patients with calcific aortic stenosis report knowing of a cardiac murmur for many years. Common symptoms of aortic stenosis include: coughing at night; fainting, especially with physical activity; fatigue; shortness of breath that worsens at night or with exertion; angina; and, visual impairments. Some patients may also experience exertional syncope, probably reflecting the inability to increase cardiac output and maintain blood pressure in response to vasodilation. Vasodepressor syncope, however, may be an operative mechanism in a portion of these syncopal episodes.
On physical examination, the harsh systolic diamond shaped (crescendo-decrescendo) murmur of aortic stenosis, loudest at the base of the heart and radiating to the carotids, is often, but not always, prominent. Low output states, obesity, or chronic lung disease may mask the findings. The murmur may radiate toward the cardiac apex, in which case the harsh component is lost; this finding may be mistaken for a second murmur. Other hallmarks of significant aortic valve stenosis include a single (pulmonic) component of the second heart sound and a sustained left ventricular apical impulse with a fourth heart sound. The slowly rising, low volume carotid arterial pulses of severe aortic stenosis may be noted in younger patients, but changes in arterial compliance often mask these findings in the elderly.
Patients with typical findings of aortic stenosis should have a detailed history-taking session with inquiry into habitual activity levels and any changes in exercise tolerance. The onset of any of the classic symptoms of left ventricular outflow obstruction, namely angina, syncope, or heart failure, in a patient with valvular aortic stenosis indicates advanced valve disease and should be carefully and promptly evaluated. The severity of symptoms is not always related to the severity of the disease. In fact, people sometimes die suddenly from aortic stenosis without having had symptoms. Symptoms usually occur when the aortic valve area narrows to less than 1 square centimeter. Critical aortic stenosis is present when the valve area is less than 0.7 square centimeters.
The electrocardiogram often shows changes of left ventricular hypertrophy. In rare instances, electrical conduction abnormality can also been seen.
The chest X-ray is seldom helpful, although occasionally heavy calcification of the valve or post-stenotic ascending aortic dilation may be seen.
With its widespread availability, two-dimensional and Doppler echocardiography has become the study of choice in the evaluation of patients with suspected valvular disease. Echocardiography allows assessment of the anatomy of the valve as well as chamber size and ventricular function. Doppler studies permit estimation of pressure gradients, as well as aortic valve area by employing the continuity equation.
With good quality echocardiography, cardiac catheterization is usually not required for diagnosis of patients with aortic stenosis. However, a cardiac catheterization is the gold standard in evaluating aortic stenosis. A pre-operative coronary angiography is generally performed in men over 40 years old and women over 50.
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