Like a multi-chambered muscular pump, the heart takes in deoxygenated blood from the body and sends out oxygenated blood to ensure proper function of vital organs. A key chamber, the left ventricle, is responsible for pumping oxygenated blood to the body and brain through the aorta. Left ventricular function is the ability of the left ventricle to do this job, and it can be affected in patients who have had heart failure or damage from an infection or heart attack.
The left ventricle consists of several elements, including the muscle itself, called the myocardium, and the mitral and aortic valves. Any of these left-sided heart areas can be affected by heart failure, and diagnostic tests can document reductions in left ventricular function. Several of these tests are non-invasive and painless.
Evaluation of left ventricular function usually begins with an exam using a type of ultrasound machine called echocardiography. The test uses sound waves to produce echocardiograms, or moving images, of a patient's beating heart. The test is ordered by a cardiologist and performed by a cardiac sonographer, who presses a type of wand against the patient's chest as the machine collects data.
During the exam, the echocardiogram records the left ventricular ejection fraction (LVEF), which is displayed as a percentage. If this percentage falls below a certain point, a patient is considered to have impaired left ventricular function, and further tests may be ordered. Healthy people with no history of heart attacks have an LVEF of about 55 percent, which means that the left ventricle pumps out more than half of its blood each time it beats.
When a cardiologist finds a reduced LVEF and needs to understand more about a patient's reduced left ventricular function, he or she may order other diagnostic tests. One is a stress test, which measures how your blood vessels and heart respond to stress. Many patients undergo stress tests by walking on treadmills or riding stationary bikes while connected to a machine that monitors their heart functions. Other patients lie on tables and receive intravenous medications designed to speed up the heart and mimic its activity during exercise.
Either type of stress test can more clearly detect and measure left ventricular heart muscle blood flow limitations and provide a clearer picture of impaired left ventricular function. When the cause of impaired left ventricular function is found, a cardiologist will treat the condition. Most forms of heart failure can be treated with a variety of cardiac medications.