Over the long run, however, the policies of the one-drop rule and segregation, in conjunction with other factors such as a long tradition of racial nationalism and white liberal support, generated a counter-reaction that led to a very different form of racial politics.
Learn about these ultrasound-like tests of the heart -- and find out what to expect -- here. Cardiac Catheterization. Cardiac catheterization -- also called a coronary angiogram -- means running a catheter into your heart. It's done to help doctors see what's going on in there, and whether they need to operate. Here's where to learn about it.
In a conventional 12 lead ECG, ten electrodes are placed on the patient's limbs and on the surface of the chest. The overall magnitude of the heart's electrical potential is then measured from twelve different angles (leads) and is recorded over a period of time (usually 10 seconds). In this way, the overall magnitude and direction of the heart's electrical depolarization is captured at each moment throughout the cardiac cycle. The graph of voltage versus time produced by this noninvasive medical procedure is referred to as an electrocardiogram (abbreviated ECG or EKG).