As a muscular pump comprised of various chambers, the heart takes in deoxygenated blood from the body and sends out oxygenated blood to ensure the proper functioning of vital organs. One key chamber, the left ventricle, is responsible for pumping oxygenated blood to the body and brain via the aorta. Left ventricular function is the ability of the left ventricle to perform this job, and it can be impaired in patients who have suffered 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-side heart areas can be affected in heart failure, and diagnostic tests can document reductions in left ventricular function. Several of these test are noninvasive and painless.
Assessing left ventricular function usually begins with an examination utilizing a type of ultrasound machine called an echocardiograph. 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 carried out by a cardiac sonographer, who presses a type of wand against the patient’s chest as the machine gathers data.
During the examination, the echocardiograph records the left ventricular ejection fraction (LVEF), which is noted as a percentage. If this percentage falls below a certain point, a patient is considered to have impaired left ventricular function, and more tests might be ordered. Healthy people who have no history of heart attacks have an LVEF of about 55 percent, which means that the left ventricle pumps out more than half of the blood it holds 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 can order other diagnostic tests. One is a stress test, which measures how the blood vessels and heart respond with exertion. Many patients take stress tests by walking on treadmills or riding stationary bicycles while attached to a machine that monitors their heart's functions. Other patients lie on tables and receive intravenous drugs designed to speed up the heart and mimic its activity during exercise.
Either type of stress test can detect and measure more clearly the blood flow limitations of the left ventricle’s heart muscle and provide a clearer picture of impaired left ventricular function. When the cause of left ventricular function impairment is found, a cardiologist will treat the condition. Most forms of heart failure can be treated with a variety of cardiac medications.