Microvolt T-Wave Alternans is an important advancement in technology for the non-invasive identification of patients at risk for ventricular tachyarrhythmias and sudden cardiac death. This is a non-invasive diagnostic test that assesses a patient’s risk of life-threatening arrhythmias and sudden cardiac death. It was the first, and remains the only, non-invasive test approved by the FDA to evaluate patients’ increased risk of these conditions. Sudden cardiac death is a pre-eminent public health problem and accounts for approximately 400,000 deaths each year in the United States of both young and older persons. (NIH 2001 Statistics) This alarming health statistic clearly calls for better ways to risk-stratify patients to determine which patients require further testing and therapy and, equally important, which patients do not. The ability to non-invasively test “at-risk” patients to determine who should receive therapy can have a significant impact in saving these otherwise lost lives. In addition, if a physician can determine early in the diagnostic process which patients are at low risk, further costly invasive diagnostic testing and therapy can be avoided, thus dramatically reducing unnecessary medical procedures and health care costs. Microvolt T-Wave Alternans test looks for minute (one-millionth of a volt) changes in the electrocardiogram morphology of the T-wave on an every-other-beat basis. The test is conducted while the patient’s heart rate is elevated through exercise, pharmacological stress or pacing. The duration of the test is usually less than 30 minutes. In order to perform the test and analyze these microvolt patterns, it is necessary to use unique equipment incorporating proprietary algorithms, highly specialized alternans sensors and trained personnel. The equipment detects tiny electrical disturbances in the heart that could mean a patient will develop an abnormally fast heartbeat. A sudden surge in heartbeat can send the heart into a dangerously fast rhythm, and then shut it down completely. Many people do not know that they are prone to this quickened heartbeat, which is the most common underlying problem in the 400,000 Americans who die annually from sudden cardiac death. Sudden cardiac death is the most common cause of death from heart disease and affects many people in Northwest Arkansas. “A large number of people die every year, and it is difficult to identify those at the greatest risk, “said Dr. James Cooper, Northwest Arkansas’ only dedicated electrophysiologist, a doctor who specializes in the electrical activity of the heart. Before Microvolt T-Wave Alternans testing, the electrical patterns only could be detected by an outpatient hospital procedure in which the patient is placed under mild sedation and the doctor gets into the heart through a vein in the leg. But this procedure is very invasive, and doctors prefer to avoid subjecting patients to the test if they are not likely to have the electrical problem. With the Microvolt T-Wave Alternans test, doctors can determine which patients need to have the full-fledged hospital procedure and which do not. The patients most likely to benefit from Microvolt T-Wave Alternans testing are those with weak or damaged heart muscles. Vulnerable patients can be treated with medication or with an implanted device called a defibrillator that slows down the heartbeat when necessary. The new technology does not identify people who are at risk of heart attacks. It focuses exclusively on the electrical disturbance that often indicates a person will develop the abnormal heart rhythms that can throw the heart out of whack. People who think they may benefit from T-Wave Alternans
testing should discuss the possibility of having the test with their physician.
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