Family history, age, high blood pressure, high cholesterol, smoking, obesity, and diabetes (just to name a few) are all conventional risk factors for heart disease. It’s commonly accepted that these conditions increase your risk of developing cardiovascular disease and stroke. While this is true, such risk factors do not account for all instances of heart disease or cardiac death. There are always some people who possess no apparent risk factors for heart disease and yet still suffer cardiac death.
Currently, conventional testing for cardiovascular disease doesn’t identify such at risk persons. Researchers at the Washington University School of Medicine in St. Louis, Missouri believe that they may have discovered a test that will identify people who are at risk for cardiac death even though they possess no conventional risk factors. According to researchers, they were able to identify at risk persons, who otherwise appeared to be healthy, by an anomaly (abnormal heart rate turbulence) in the response to left ventricle “early” or ventricular premature beat (VPB).
Ventricular premature beats are not an uncommon occurrence. A VPB occurs when the left ventricle misfires and beats earlier than it should. This results in two difficulties for persons with VPB. First, blood flow is decreased because the heart is unable to fill up with a sufficient amount of blood. As a result, heart rates increase as the heart tries to keep up with the demand. Second, VPBs cause the heart to empty much more quickly than normal. This results in a heart that is fuller than normal on the second beat because of the additional time to fill the heart. To compensate for the additional blood that is present, the heart slows down.
Heart rate turbulence is the heart’s response to VPBs. The normal response to VPB is to compensate by alternately speeding up and slowing down to compensate for the VPB. Heart rate turbulence can be tracked through the use of a Holter monitor, a device that is worn for 24 hours which records the heart’s electrical (electrocardiogram) signals.